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Invalidate cache over multiple applications. <p>We have a suite of applications including a website, a client application and multiple windows services. All these applications work on the same dataset and use an in-memory cache. Of course, this setup fails when one of the applications does something that invalidates the cache. I'm looking for a solution that will allow me to invalidate the cache across the applications. We have some ideas, but I'm sure the collective minds of the internet can give us a better solution.</p>
<p>Some details:</p>
<ul>
<li>this is a legacy application, which means we would like to keep the changes as non-invasive as possible</li>
<li>We're hesitant to introduce another moving piece to the solution. So using an external cache is out.</li>
</ul>
| 0non-cybersec
| Stackexchange |
Grandma found this at goodwill. Any help is appreciated!. | 0non-cybersec
| Reddit |
Can `template` keyword qualifier cause code to compile successfully, but differently?. <p>I'm reading about the template keyword qualifier (<a href="https://www.ibm.com/support/knowledgecenter/SSPSQF_9.0.0/com.ibm.xlcpp111.aix.doc/language_ref/keyword_template_qualifier.html" rel="noreferrer">https://www.ibm.com/support/knowledgecenter/SSPSQF_9.0.0/com.ibm.xlcpp111.aix.doc/language_ref/keyword_template_qualifier.html</a>, and <a href="https://stackoverflow.com/questions/610245/where-and-why-do-i-have-to-put-the-template-and-typename-keywords">Where and why do I have to put the "template" and "typename" keywords?</a>), but there's still something that confuses me.</p>
<p>Is it possible to have code like this, that compiles successfully, but results in two different operations?</p>
<pre><code>SomeObjectInstance.template some_function();
SomeObjectInstance.some_function();
</code></pre>
| 0non-cybersec
| Stackexchange |
Looking for a proof that the resultant is the product of the differences of roots. <p>I'm trying to find a general proof to an exercise given in Garrity et al's book, Algebraic Geometry: A problem-solving approach. </p>
<p>The problem is this: Given two polynomials f and g, show that for each pair of roots, f(r) = 0, g(s) = 0, that (r - s) divides the resultant.</p>
<p>There is a book of selected answers, but somewhat disappointingly, the solution is given as a brutal appeal to algebra. Moreover, the result is only given for quadratic polynomials. </p>
<p>It seems cited in a few places that the resultant, defined as the determinant of the Sylvester matrix of two polynomials $f = \lambda_1\prod (x - r_i)$ and $g = \lambda_2 \prod (x - s_i)$, is equal to the product $\prod r_i - s_i$. But so far, I have been unable to find a general proof of this fact.</p>
<p>Would anyone either mind sketching the proof, or else pointing me to a resource which does?</p>
| 0non-cybersec
| Stackexchange |
I keep getting an error that my app needs to be verified when either I or another user try to authorize with OAuth2. What does that mean?. <p>I received this error when trying to authorize my app with my own account:</p>
<pre><code>Your project is trying to access scopes that need to go through the verification process.
{invalid=https://www.googleapis.com/auth/contacts}
If you need to use one of these scopes, submit a verification request. Learn More
</code></pre>
<p>When I use a different account, the error message is different:</p>
<pre><code>This app hasn’t been verified to access:
{invalid=https://www.googleapis.com/auth/contacts}
Are you the developer? If this project needs these scopes, sign in to an account with access to edit your project and try again.
If not, contact the developer for help.
</code></pre>
| 0non-cybersec
| Stackexchange |
O.G. | 0non-cybersec
| Reddit |
Colorado students’ ‘Harlem Shake’ flight performance prompts Federal Aviation Administration investigation. | 0non-cybersec
| Reddit |
Mmmmm tasty...….. "funnel cakes".. | 0non-cybersec
| Reddit |
Python Gensim: how to calculate document similarity using the LDA model?. <p>I've got a trained LDA model and I want to calculate the similarity score between two documents from the corpus I trained my model on.
After studying all the Gensim tutorials and functions, I still can't get my head around it. Can somebody give me a hint? Thanks!</p>
| 0non-cybersec
| Stackexchange |
MySQL: Adding an IF condition to trigger?. <p>We've got a trigger that is overwriting the <code>uuid</code> value before insert.</p>
<p>The vers.1 of our API depended on the DB to generate the UUID's, but I'm writing v2 which is using a library that generates the UUID's in the code before sending the <code>INSERT</code> query.<br>
As such, I need to update our trigger so that the new uuid's created via my Model can get stored without being overwritten.</p>
<p>I'm working in PhpMyAdmin (for ease) and our original trigger looks like this:</p>
<pre><code>DROP TRIGGER IF EXISTS `init_uuid_company`//
CREATE TRIGGER `init_uuid_m3_company` BEFORE INSERT ON `company`
FOR EACH ROW SET NEW.uuid = UUID()
//
</code></pre>
<p>Obviously, the delimiter is set to <code>//</code>.</p>
<p>My latest attempt looks like:</p>
<pre><code>DROP TRIGGER IF EXISTS `init_uuid_company`//
CREATE TRIGGER `init_uuid_company` BEFORE INSERT ON `company`
FOR EACH ROW BEGIN
IF(NEW.uuid IS NULL OR NEW.uuid = '') THEN
SET NEW.uuid = UUID();
END IF;
//
</code></pre>
<p>But it's throwing an error saying <code>You have an error in your SQL syntax ... near '' at line 5</code></p>
<p>Unless I'm counting wrong, line 5 is the <code>SET</code> line. No quotes used there.<br>
What am I missing?</p>
| 0non-cybersec
| Stackexchange |
Guy films his multiple attempts at train hopping to Montauk. | 0non-cybersec
| Reddit |
MRW I'm fooling around and remember that school starts in less than a month. | 0non-cybersec
| Reddit |
include of non-modular header inside framework module 'Bolts BFCancellationToken'. <p>I just downloaded the Parse sample project, installed LiveQueries pod and nothing else. When I try to build it, it pops the two errors below.. What's wrong?</p>
<p><a href="https://i.stack.imgur.com/N4v1V.png" rel="noreferrer"><img src="https://i.stack.imgur.com/N4v1V.png" alt="enter image description here"></a></p>
| 0non-cybersec
| Stackexchange |
[4E] Why do you tend not to recommend Essentials to new players?. I haven't been posting as much as I have in the past, but while lurking, I've noticed that many of the "new player"/"getting started" threads get flooded with "Player's Handbook / Dungeon Master's Guide / Monster Manual" ... after recommending the Red Box as a starting point!
Now, I can understand the attraction to the old "Core" rulebooks. They're more in line with tradition, they're hardcover, etc. But the facts of the matter are that they've been errata'd to hell and the Essentials line-up does an arguably better job at presenting the game with up to date rules and better class builds.
Am I missing something here? At least, if you're going to recommend the "Core" books instead of Essentials, why not recommend the free Getting Started / Keep on the Shadowfell PDFs instead of buying the Red Box, which has very different class builds. | 0non-cybersec
| Reddit |
The Cloture of Deconstruction: A Mahayana [Buddhist] Critique of Derrida. | 0non-cybersec
| Reddit |
Found on Quora, current BTC price is 13800$.. | 0non-cybersec
| Reddit |
Mob Spawner 1.8 bug? Please Help.. Hey guys, so I just recently started playing Minecraft with a couple friends and we are on 1.8.9 (newest version) and I need help. I have built 4 standard mob traps (8x8 pads with water in the middle, trap doors and a 22 block drop for xp) and I build them all about 200 height to avoid spawns on the ground. Now I have built 4 of these all at different heights, and I have gotten about 20 mobs to drop total.
Is there some known bug, error, or some height cap that I am unaware of?
Please help.
| 0non-cybersec
| Reddit |
biggby breached again, credit card data compromised!. | 1cybersec
| Reddit |
I had never seen this one 😂😂😂. | 0non-cybersec
| Reddit |
Ways to publish new result for NP-complete problem. <p>I am working on an NP-Hard problem. The state-of-the-art algorithm for my problem runs in O(3^n) time using dynamic programming approach. I changed the way the dynamic program works for my problem and it reduces the time complexity to O(n2^n). But, the main problem with my approach is the optimal result. More than 95% of the time my approach is giving the optimal output. Is there any way to publish my work by showing the results for the different data set. I am unable to prove the approximation ratio. Please give me any suggestion regarding this. Note: The Input size is 2^n</p>
| 0non-cybersec
| Stackexchange |
[ART] anyone else feel like they pull off their best fits in the fall/winter?. | 0non-cybersec
| Reddit |
How to create an HMAC in crystal-lang. <p>See the <a href="https://crystal-lang.org/api/0.23.0/OpenSSL/HMAC.html" rel="nofollow noreferrer">OpenSSL::HMAC documentation</a>.</p>
<p>I am trying this:</p>
<pre><code>require "openssl"
puts OpenSSL::HMAC.hexdigest(:sha256, "secret key", "data")
</code></pre>
<p>and I am getting this error:</p>
<blockquote>
<p>undefined constant OpenSSL::HMAC</p>
</blockquote>
<p>Other OpenSSL methods are working fine, like <code>OpenSSL::Digest.new("SHA256")</code>.</p>
<p>What am I doing wrong?</p>
| 0non-cybersec
| Stackexchange |
Removing "www." from domain name and SEO. <p>We are doing a big redesign work on our website, and at least 50% of the website folders will be moved to new places with different names (i.e. many URL will be changed). Sure, Google will need some time to index new pages and we expect our SERP positions will be not so good as they are now for some time.</p>
<p>We also have an old idea to remove <code>www</code> from our domain name. It seems, it's the right time to do these two works together with publishing the website with updated contents. Or is it better from SEO perspective first publish the new contents, and only after some time, when our SERP positions will return to prior results, tell Google that the domain name without <code>www</code> is our preferred domain name?</p>
| 0non-cybersec
| Stackexchange |
Small caps given different letter sizes in acrobat pdf viewer. <p>I am using \textsc{} in my latex document and in the pdf view for mac everything is fine, however when opening the document in Adobe Acrobat Reader on my windows machine the small cap letters are not all the same size. </p>
<p>In PDF viewer:</p>
<p><a href="https://i.stack.imgur.com/HpQBm.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/HpQBm.png" alt="PDF viewer on Mac"></a></p>
<p>In Adobe acrobat:</p>
<p><a href="https://i.stack.imgur.com/XldWd.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/XldWd.png" alt="Adobe Acrobat Reader"></a></p>
<p>(Sorry about different sizes in the images, but the problem is still visible)</p>
| 0non-cybersec
| Stackexchange |
Strong Markov Property for Markov Chains - Statement Verification. <p>I suspect that my handwritten lecture notes for the Strong Markov Property are wrong. I'd appreciate corrections to them.</p>
<p>We first define the following:</p>
<blockquote>
<p>A random variable $\tau$ is called a stopping time if $\{\tau \leq n\}$ depends only on $X_0, X_1, \ldots X_n$.</p>
</blockquote>
<p>We now state the theorem:</p>
<blockquote>
<p>Suppose that we have a Markov chain $(X_n)$ with transitional probability matrix $P$, initial distribution $\lambda$, and stopping time $\tau$. Let $f = f(X_\tau, X_{\tau +1}, X_{\tau + 2}, \ldots)$ be a function.Then $\mathbb{E}_\lambda[f(X_\tau, X_{\tau + 1}, X_{\tau + 2}, \ldots) \mid X_0, X_1, \ldots, X_\tau] = \mathbb{E}_\color{red}{X_\tau}[f(X_0, X_1, X_2, \ldots)]$.</p>
</blockquote>
<p>Marked in red is what I think is wrong. Should this instead be $\tau$? Are there any other mistakes in the statement of this theorem?</p>
| 0non-cybersec
| Stackexchange |
I built a pedalboard with my dad over "spring break.". | 0non-cybersec
| Reddit |
For some reason my greyhound just stood in the doorway, staring at me.. | 0non-cybersec
| Reddit |
Nothing Clever. This is just dope.. | 0non-cybersec
| Reddit |
How to install texlive 2011?. <p>i'm not quite sure whether the problem with my texlive installation isn't sitting in front of the computer but i just cannot get it to work.</p>
<p>The first thing I did was download the installer from the texlive homepage, run it and try the installation with all the options preselected.</p>
<p>When I tried to install "gummi" (latex editor) from its ppa afterwards it was telling me it had some uninstalled dependencies (mostly texlive 2009 packages from the ubuntu repositories).</p>
<p>Then I went back and started reading some more on the installation topic and there was a vague mentioning of having to set PATH for the installation. I couldn't figure out how to do that so I found the option in the installer "create symlinks in standard directories" which I figured was an automated option of the PATH settings.</p>
<p>Now I tried to install gummi once more and it still came back with all the lacking dependencies. I figured I'd try just installing it but now i'm sitting there with a bowl of nothing - even the installation of 13 of the packages from the repositories failed with errors, for example:</p>
<pre><code>dpkg: dependency problems prevent configuration of texlive-latex-extra:
texlive-latex-extra depends on texlive-pictures (>= 2009-1); however:
Package texlive-pictures is not configured yet.
texlive-latex-extra depends on texlive-latex-base (>= 2009-1); however:
Package texlive-latex-base is not configured yet.
</code></pre>
<p>Now i'm wondering where I went wrong and whether there is somebody who could give me a fool-proof explanation on how to install the 2011 texlive. Unfortunately I couldn't find a good explanation by raiding google.</p>
<p>Thanks hell of a lot in advance for any help on those matters
Best regards</p>
| 0non-cybersec
| Stackexchange |
Unattended installation of pkg file. <p>Is there any possibility to create a unattended installation of an pkg package?</p>
<p>E.g. creating a mpkg and running a script which installed the package via console and installer.</p>
<p>Background:
I had to deploy a package to many osx enduser. We have no apple desktop and no root access to these machines. these is an preconfigured pkg package, but if the user launch it in normal way, the pre configuration will be overwritten.
On windows I realize this with an selfexecutable archive which launches an msi with silent installation. On linux I build rpm/deb packages but on osx I didn't find any proper way :(</p>
| 0non-cybersec
| Stackexchange |
Recreation of reddit history. | 0non-cybersec
| Reddit |
Secret Santa Gift! Thank you!. | 0non-cybersec
| Reddit |
Judge smacks down Homeland Security: "Our homeland will not be secure by these rascals"; orders them to return money they seized from traveling family.. | 0non-cybersec
| Reddit |
WIBTA if I declined my friends request to do a choreographed dance at her wedding?. My best friend is getting married in October and I am a bridesmaid. She has recently asked me and the other bridesmaids if we would be okay with doing a surprise pre-choreographed dance at the reception. I panicked and said I would even though I can't think of anything worse. I am a really horrible dancer and find the whole thing to be a bit cringey, I've been anxious with the thought of having to do this at her wedding ever since she asked.
Would I be the asshole if I told her I didn't want to do it? I don't want to ruin her day and make it about me but I also want to be able to enjoy the day and the lead up! 😊 Thanks in advance!
UPDATE: I told her I wasn't comfortable with it and she was 100% fine with it, no problems at all. Thanks everyone for helping me make my decision 😊😊😊 | 0non-cybersec
| Reddit |
How to fix this before I paint?. | 0non-cybersec
| Reddit |
Showing a particular integral operator is trace class. <p>Let $f$ and $P$ be continuous, integrable functions $\mathbb{R} \to \mathbb{C}$ vanishing at $\pm \infty%$. Concisely, $f,P \in C_0(\mathbb{R}) \cap L^1(\mathbb{R})$. Also, assume that $P$ is real-valued. </p>
<p>Define an integral kernel $K: \mathbb{R}^2 \to \mathbb{C}$ by
$$ K(x,y) = f(x-y) \left( \exp\left(i \int_x^y P(z) \ dz \right) - 1 \right).$$
It's not hard to see that $K$ defines bounded operator $\xi \mapsto K \cdot \xi$ on $L^2(\mathbb{R})$ by
\begin{align*}
(K \cdot \xi)(x) = \int K(x,y) \xi(y) \ dy && \xi \in L^2(\mathbb{R}).
\end{align*} For example, one can apply Theorem 1.6 in Conway's <em>A Course in Functional Analysis</em>. I have reason to believe this operator is trace class. Any thoughts about how this could be proved would be appreciated. I'm not sure how necessary all these hypotheses are.</p>
| 0non-cybersec
| Stackexchange |
These USB flash drives show how full they are. | 0non-cybersec
| Reddit |
o..o... Got it, here hooman!. | 0non-cybersec
| Reddit |
How to use spot instance with amazon elastic beanstalk?. <p>I have one infra that use amazon elastic beanstalk to deploy my application.
I need to scale my app adding some spot instances that EB do not support.</p>
<p>So I create a second autoscaling from a launch configuration with spot instances.
The autoscaling use the same load balancer created by beanstalk.</p>
<p>To up instances with the last version of my app, I copy the user data from the original launch configuration (created with beanstalk) to the launch configuration with spot instances (created by me).</p>
<p>This work fine, but:</p>
<ol>
<li><p>how to update spot instances that have come up from the second autoscaling when the beanstalk update instances managed by him with a new version of the app?</p>
</li>
<li><p>is there another way so easy as, and elegant, to use spot instances and enjoy the benefits of beanstalk?</p>
</li>
</ol>
<p><strong>UPDATE</strong></p>
<p>Elastic Beanstalk add support to spot instance since 2019... see:
<a href="https://docs.aws.amazon.com/elasticbeanstalk/latest/relnotes/release-2019-11-25-spot.html" rel="nofollow noreferrer">https://docs.aws.amazon.com/elasticbeanstalk/latest/relnotes/release-2019-11-25-spot.html</a></p>
| 0non-cybersec
| Stackexchange |
Tor with Windows RT. <p>I get as present a used Surface 1 with Windows RT 8.1.</p>
<p>Is there a possiblity to use Tor on a Windows RT Tablet?</p>
<p>Thanks for your Help</p>
| 0non-cybersec
| Stackexchange |
Methane warning in New Zealand mine was ignored 21 times before the 2010 explosion that killed 29 workers. | 0non-cybersec
| Reddit |
gb4e package causing capacity errors. <p>I was using this:</p>
<p><a href="http://www.essex.ac.uk/linguistics/external/clmt/latex4ling/examples/gb4e/" rel="noreferrer">http://www.essex.ac.uk/linguistics/external/clmt/latex4ling/examples/gb4e/</a></p>
<p>To try and create numbered examples in my document.</p>
<p>However, when I load it and put the example <code>exe</code> in that link in one of the separate Tex files (<code>Introduction.tex</code>) I include in <code>main.tex</code>, I get:</p>
<pre><code>./Chapters/Introduction.tex:14:
TeX capacity exceeded, sorry [parameter stack s
ize=10000].
\gb@ifnextchar #1#2#3->
\let \reserved@d =#1\def \reserved@a {#2}\def \reserv...
l.14 ... and political news \cite{washington_post}
. More importantly, when ...
</code></pre>
<p>Which is not even referring to the <code>exe</code> example I inserted but a couple of blocks of tex above it.</p>
<p>For info, here is my full code before my document begins:</p>
<pre><code>\documentclass{report}
% [fontsize=11pt,border=5pt]
% standalone for the tree
\usepackage{forest}
% This overrides warnings like http://tex.stackexchange.com/questions/52576/difference-between-bookmark-levels-greater-than-one-what-does-this-mean
\usepackage{bookmark}
\usepackage{amsmath}
\usepackage{subcaption}
\usepackage{standalone}
\usepackage[round]{natbib}
\usepackage[T1]{fontenc}
\usepackage{lmodern}
\usepackage[utf8]{inputenc}
% This is for hyperlinks
\usepackage{hyperref}
\hypersetup{
colorlinks=true,
linkcolor=blue,
filecolor=magenta,
urlcolor=cyan,
}
\urlstyle{same}
% Not sure why I need to use this
% \usepackage{graphicx}
% \graphicspath{ {images/} }
% \usepackage[pdftex]{graphicx}
% fontsize=11pt,twoside]{scrartcl}
% This is for numbered examples
\usepackage{gb4e}
</code></pre>
<p>Would appreciate some help as I feel like my Latex is very messy here.</p>
| 0non-cybersec
| Stackexchange |
Surface pro 3 Ubuntu 16.04. <p>Hey guys I have successfully install Ubuntu on my device using rEFInd and updated the kernel to 4.16.2
Everything is working but the WIFI doesn't work correctly.. If I open my device after suspend it changes from the WIFI logo to the Ethernet logo and then it disconnects and says "Activation failed" and err (24) </p>
<p>Can anyone help me to solve this problem?
Thanks.</p>
| 0non-cybersec
| Stackexchange |
Reddit, what is the worst thing that has happened to your genitals?. Embarrassingly, I was jacking off with my pants on, and I got rug burn inside my penis, it hurt to wear pants.
Another time when I was young and stupid, I didn't do clean up, just put my underwear back on, so after a while, the leftover semen crusted on my phallic member (It was winter, windy, and I wore sweat pants, because they looked comfy), and it was god awfully painful to have an erection. I learned my lesson that day, NEVER forget the tissues.
And the worst non masturbatory one, I have a urethral stricture, and I had to get a cystoscopy.
I have ashamed my ancestors, now it's your turn.
EDIT: I almost forgot, I asked my brother when he was two to give me a hug, he flat out ran into me and bit my dick through my pants, I have a scar on my head now.
EDIT#2: Hey guys, I want to thank you for getting this up to the front page. I know it sounds all smug and shit, but it really does mean a lot to me. | 0non-cybersec
| Reddit |
Man saves 321 people on China's most frequented suicide spot. | 0non-cybersec
| Reddit |
What is the safe way to replace Ubuntu 12.04 (installed in dual-boot with W7) with OpenSUSE 13.1?. <p>This question is related to:
<a href="https://askubuntu.com/questions/26894/how-can-i-remove-ubuntu-from-my-dual-boot-and-replace-it-with-another-distributi">How can I remove Ubuntu from my dual-boot and replace it with another distribution?</a></p>
<p>Laptop: DELL XPS L502X, 64-bit</p>
<p>Existing OS: Windows 7 + Ubuntu 12.04 (in dual-boot)</p>
<p>I tried to proceed with the installation DVD of OpenSUSE 13.1, at the stage where it asks "New Installation" or "Update an existing system". I do not know what to do next, I am just stuck here, I checked in both the options. The new installation seem to wipe the existing OS and the update will not install the automatic configurations (with all programs).
I am afraid to loose windows. I do not want to install windows again because it is from the manufacturer when i bought the laptop.</p>
<p>Anyone can provide a step-by-sept guide, or any external link ?</p>
| 0non-cybersec
| Stackexchange |
Give me your worst.. | 0non-cybersec
| Reddit |
Can somone tell me HOW to put a virus to somone PC or LAPTOP just with USB?. I am a hackergirafe | 1cybersec
| Reddit |
Help. Is there a rope type material that can be tied to a weather balloon all the way to space?. This way it can be slowly pulled back instead of tracking it where it falls using gps. Can this work? What material would work? Any where i can read about this? | 0non-cybersec
| Reddit |
[Request] Anything like Gotham and Daredevil. My wife and I have finished both Gotham and Daredevil. What else is available on Netflix that is similar?
Thanks for your help! | 0non-cybersec
| Reddit |
You could recycle those leftover diaper boxes… or you could make your own AT-AT out of them | Offbeat Mama. | 0non-cybersec
| Reddit |
Saw this at a festival the other day.... | 0non-cybersec
| Reddit |
Initial values problem with absolute value. <p>I've some doubts about initial values problems involving differential equation with absolute values. </p>
<p>For example if I have a differential equation like $y'=|x+1|$ with initial condition $y(3)=-2$, since $3>-1$ I can trascurate the absolute value and solve $y'=x+1$, is it correct?</p>
<p>But if the condition is for instance $y(-1)=2$ then I must consider the two different cases? That is, $y'=x+1$ if $x>-1$ and $y'=-x-1$ if $x<-1$</p>
<p>Is this the right way to solve this kind of problems?</p>
| 0non-cybersec
| Stackexchange |
Taking roots in simple linear algebraic groups . <p>Suppose $G$ is a simple (linear) algebraic group over an algebraically closed field of characteristic zero, that $n$ is a positive natural number, and that $g\in G$. Can we always find an $h\in G$ such that $h^n=g$?</p>
<p>(It appears to be possible to check this for the classical algebraic groups by direct computations in each case, but covering the exceptional Lie Algebras this way seems like it might be tricky, and anyhow, I'm inclined to think that a case analysis is probably not the optimal way of approaching this problem!)</p>
<p>Note added: Kovalev made a comment showing that the answer is `no' in general. The counterexamples appear to revolve around non-semisimple elements. I wonder whether the answer becomes positive if one restricts oneself to $g$ of finite order?</p>
| 0non-cybersec
| Stackexchange |
Canadians make their way down a muddy road at the Battle of Vimy Ridge, 1917. [640x509]. | 0non-cybersec
| Reddit |
A fast way to use a ssh-client bypassing ISP NAT+Firewall rules. <p>My home ISP is using a NAT based network, in my in house router the modified the router firmware. Then I don't have access to all router features. Add this to the fact they are blocking all data output to 22 port, then I don't have a easy way to use ssh-client. After 2 weeks of customer service request, I received only one tech visit, and the "professional" don't know what to do.</p>
<p>I know that I can use tools like <code>torsocks</code> to connect ssh via tor relays it works but it is too slow. And normally I use a environment with <code>ssh</code>+<code>tmux</code>+<code>vim</code> to program in a cloud host.</p>
<p>Another option that I have is use the in house ISP modem as bridge. It can solve, but I would need a 5G router, that I haven't here and is a quite expensive in the range to cover that I have. And as they have total remote control to they router software, I don't know when they will remove this option.</p>
<p>Keep in mind that anonymity is not a problem since I am in my house and I just want to access servers that I have legal access.</p>
<p>How can I use a local proxy (and which) to bypass this NAT restriction?</p>
<p>Or there is a faster relay config to solve it ?</p>
| 0non-cybersec
| Stackexchange |
Eastern Conference Position Battles. | 0non-cybersec
| Reddit |
Reminiscing the good old days.. | 0non-cybersec
| Reddit |
Miserable about my tiny budget life and no signs of changes about that in the future.. First time posting here, just didn't know where else to go...
I [F, 32, Dutch] have been living under the minimum wage level my whole adult life. Due to Aspergers' Syndrome and related problems I haven't been able to keep a steady job and I have been living on a government allowance {welfare? I don't know how to translate it from Dutch, but I get an amount of money every month because I can't work because of medical reasons}. I know I am very lucky to life in a country that has this resource for me, but money is so tight. After I paid my monthly things like rent, electricity, healthcare, phone bill, etc, etc, I just have a bit of money left to buy groceries and then maybe have about 60 euros a month left for personal care, unforeseen things or maybe clothes if I'm lucky. I don't have a car, I do not drink, smoke or use drugs, I have no expensive hobbies... I only have a few hundred euros saved and I sometimes need to dip into that to even buy food, so saving is an issue too.
I try to be upbeat and see it as some kind of challenge for myself to live on a low budget, but lately that's been really hard. It dawned on me that this might be the situation for the rest of my life and that I do not have anything of a safety net finacially when something happens. It is just suffocating me. It keeps me down, keeps my life small, makes me worry every day, I can't even have a social life, a day out of town, or a real sense of freedom to do what I like, want or even need. I cant even look the way I want, because I can't afford the clothes I like, and I am not even talking about wanting brand clothes, but I am forced to buy stuff at the cheapest stores possible. Everything in this life depends on money and I do not see how my life will get comfortable when I have no prospect of generating more income.
Last night a girlfriend confided in me that she had money problems because she bought more home décor items than her budget could handle and now she has to pay off her debt the next couple of months and will be forced to not buy any 'luxury items' for that time. I didn't know whether to laugh or cry while I was thinking about the state of my own bank account.
I know I might sound like I feel very sorry for myself, but I am just tired. And I do not see how I will go on years and years like this. I feel freaking poor. For the first time in all this time living on a budget I really feel poor. And I am afraid that it might lead to depression, something I have struggled with in the past. I am a very independent woman, self-reliance is very important to me. And now I feel very restricted. Also, taking money from people makes me feel like a leech. Which is pretty unhelpful, I know, but I have my pride I think haha.
So... are any of you in the same boat? How are you coping with it, what are your insights? Does someone have the golden tip? Something other than marrying a wealthy person, of course... | 0non-cybersec
| Reddit |
Playing .ogg video files on Windows XP. <p>By default, Windows XP has no support for .ogg video files. What can be used to read and play these files?</p>
| 0non-cybersec
| Stackexchange |
proof that a property is chart independent on a manifold. <p>A textbook gives the following definition of tangent curves on a smooth manifold. </p>
<blockquote>
<p><a href="https://i.stack.imgur.com/3xOEA.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/3xOEA.png" alt="enter image description here"></a> p23</p>
</blockquote>
<p>It then asks: </p>
<blockquote>
<p>Show that the definition does not depend on the choice of local coordinates in a neighborhood of P.</p>
</blockquote>
<p><strong>My suggestion for a proof is as follows:</strong></p>
<p>We have the already given chart map $x: M \to R^d$. Pick any arbitrary different chart map $y:M\to R^d$. Then the chart transition map $y\circ x^{-1}:R^d \to R^d$ is a smooth map (since both chart maps are smooth by assumption).</p>
<p>Then simply take the second equation in the definition of tangent curves and apply the chart transition map (which is possible since both sides of the equation are an instance of $R^d$ since they are derivatives in the charts, not on the manifold):</p>
<p>$$(y\circ x^{-1})^i\left(\frac{d}{dt}|_0x^i(\gamma _1(t))\right )=(y\circ x^{-1})^i\left(\frac{d}{dt}|_0x^i(\gamma_2(t))\right )$$
<strong>Edit</strong>: I see now that the above equation doesn't make sense, since it is a map $R^d\to R$, while its arguments are $R$.</p>
<p><strong>Now here is the step I am most uncertain about:</strong></p>
<p>Since the transition maps are smooth maps, they preserve the differential structure of the two charts. Hence we can shift the transition maps inside the differential operator:</p>
<p>$$\frac{d}{dt}|_0\left(((y\circ x^{-1})^i \circ x^i)(\gamma _1(t))\right )=\frac{d}{dt}|_0\left(((y\circ x^{-1})^i \circ x^i)(\gamma _2(t))\right )$$</p>
<p>Hence</p>
<p>$$\frac{d}{dt}|_0y^i(\gamma _1(t) )=\frac{d}{dt}|_0y^i(\gamma _2(t) )$$</p>
<p>This concludes the "proof". However, I feel like I have done something wrong, but I don't know what.</p>
<p><strong>So is this "proof" correct, and if not, why, and how would I fix it?</strong></p>
| 0non-cybersec
| Stackexchange |
Unable to configure WinRm https listener. <p>I am trying to configure <code>winrm</code> https listener on a windows machine. Earlier i had followed <a href="http://blogs.technet.com/b/meamcs/archive/2012/02/25/how-to-force-winrm-to-listen-interfaces-over-https.aspx" rel="nofollow noreferrer">WinRm https listener configuration</a></p>
<p>The above solution worked for me.</p>
<p>But now i have deleted the listener and want to configure the winrm again using
<code>winrm quickconfig -transport:https</code> but i am unable to do it as its throwing error</p>
<blockquote>
<p>WSManFault</p>
<p>Message = Cannot create a WinRM listener on HTTPS because this machine does not have an appropriate certificate. To be used for SSL, a certificate must have a CN matching the hostname, be appropriate for Server Authentication, and not be expired, revoked, or self-
signed.</p>
</blockquote>
<p>Even deletion of the https listener i am unable to do quick config .i feel there is a need to remove the thumbprint from some place but not sure from where all.</p>
<p>I have gone through one of the links where Jared stated that we need to manually delete the thumbprint: <a href="https://serverfault.com/questions/589607/automatically-reconfigure-winrm-https-listener-with-new-certificate#">Automatically reconfigure WinRM HTTPS listener</a></p>
| 0non-cybersec
| Stackexchange |
Gmail blocking any e-mail that mentions client's specific domain. I am doing some web dev work for a client that involved repairing a hacked site. Everything has been back to normal for about \~2 weeks and I've also set up DMARC, DKIM, and SPF records for their domain that satisfies the checklist at [https://toolbox.googleapps.com/apps/checkmx/check](https://toolbox.googleapps.com/apps/checkmx/check).
Despite this, Gmail continues to block any e-mail that just mentions their domain name in the body with the following:
>Message rejected. See [https://support.google.com/mail/answer/69585](https://support.google.com/mail/answer/69585) for more information.
I've tried the e-mail security stuff I mentioned before as well as contacting Google via [https://support.google.com/mail/contact/msgdelivery](https://support.google.com/mail/contact/msgdelivery). No response there. I've also verified the website's domain name was not on any blacklist I could find.
At a bit of a loss and would appreciate a point in the right direction. Thank you in advance. | 0non-cybersec
| Reddit |
Let $P$ a $\pi$-system. then the generated $\lambda$-system for $P$ coincides with the generated $\sigma$-algebra for $P$.. <p>Let <span class="math-container">$P$</span> a <span class="math-container">$\pi$</span>-system. then the generated <span class="math-container">$\lambda$</span>-system for <span class="math-container">$P$</span> coincides with the generated <span class="math-container">$\sigma$</span>-algebra for <span class="math-container">$P$</span>.</p>
<p><span class="math-container">$D(P)=\sigma(P)$</span></p>
<p>where <span class="math-container">$D(P)$</span> is the Dynkin system.</p>
<p><b>Definition:</b> We say <span class="math-container">$C$</span> is a <span class="math-container">$\lambda$</span>-system if: <br>
i) <span class="math-container">$\emptyset\in C$</span><br>
ii) <span class="math-container">$A,B\in C$</span> with <span class="math-container">$A\subset B$</span> then <span class="math-container">$B-A\in C$</span><br>
iii) <span class="math-container">$\forall (A_n) \text{ Where this is a increasing sequence}\subset C \implies \bigcup A_n\in C$</span></p>
<p><b>Definition:</b> We say <span class="math-container">$C$</span> is a <span class="math-container">$\pi$</span>-system if <br>
i)<span class="math-container">$A,B \in C$</span> then <span class="math-container">$A\cap B\in C$</span></p>
<p><b>My attempt:</b></p>
<p>I want use this result: Let <span class="math-container">$A$</span> an algebra and <span class="math-container">$m$</span> a monotone class such that <span class="math-container">$A\subset m$</span> then <span class="math-container">$\sigma(A)\subset m$</span></p>
<p>I make this part of the proof.</p>
<p>Let see <span class="math-container">$D(P)\subset \sigma(P)$</span></p>
<p>As <span class="math-container">$P$</span> is a <span class="math-container">$\pi$</span>-system then for <span class="math-container">$A,B\in P$</span> we have <span class="math-container">$A\cap B\in P \tag 1$</span> .</p>
<p>By hyptohesis we have P is a generated Dynkin system then:</p>
<p>i) <span class="math-container">$\emptyset \in P$</span><br>
ii) <span class="math-container">$A,B\in P\text{ with }A\subset B\implies B-A\in P$</span><br>
iii)<span class="math-container">$\forall (A_n)\uparrow\subset P\implies \bigcup_{n=1}^\infty A_n\in P$</span></p>
<p>Then of <span class="math-container">$(1)$</span> and the hypothesis of <span class="math-container">$D(P)$</span> we have <span class="math-container">$D(P)$</span> is a ring and moreover is a monotone class, then by theorem <span class="math-container">$D(P)$</span> is a <span class="math-container">$\sigma$</span>-ring</p>
<p>This implies
<span class="math-container">$\forall A_n\in P , \,\bigcap_{n\in\mathbb{N}} A_n\in P \tag2 $</span></p>
<p>Moreover, </p>
<blockquote>
<p>I need prove if <span class="math-container">$A\in P\implies A^c\in P$</span></p>
</blockquote>
<p>For the other implication:</p>
<p>Let see <span class="math-container">$\sigma(P)\subset D(P)$</span></p>
<p>Let <span class="math-container">$B_0=\emptyset$</span>, <span class="math-container">$B_1=A_1$</span>, <span class="math-container">$B_2=A_2-A1$</span>... <span class="math-container">$B_n=A_n-A_{n-1}$</span></p>
<p>Then <span class="math-container">$(B_n)_{n\geq 1}$</span> is a increasing sequence such that <span class="math-container">$(B_n)_{n\geq 1}\in P$</span></p>
<p>This implies <span class="math-container">$\bigcup B_n \in P$</span> this is for <span class="math-container">$\sigma(P)$</span></p>
<p>Then, <span class="math-container">$\sigma(P)$</span> is a dynking system. But <span class="math-container">$D(P)$</span> It's the smallest Dinking system. this implies</p>
<p><span class="math-container">$\sigma(P)\subset D(P)$</span></p>
| 0non-cybersec
| Stackexchange |
Relative interior of the sum of two convex sets. <p>I'd like to show ri(C1-C2)=ri(C1)-ri(C2) without using the fact that relative interior is preserved under linear transformations. I.e. Is there a way to show this by showing both inclusions?</p>
| 0non-cybersec
| Stackexchange |
A Polish Joke. A man walks up to a counter and says to the clerk, "Sir, give me your finest polish sausage!"
The man looks back at him confused. He then asks, "Sir, are you by any chance Polish?"
The first man looks back at him shocked and appalled. "How dare you assume I'm polish just because I asked for polish sausage! If I had asked for a taco, would you ask if I was Mexican? If I had asked for spaghetti, would you have assumed I was Italian? I can't believe you would assume something like that!"
The clerk looks back at him and says, "No sir, I assumed you were Polish because this is a hardware store." | 0non-cybersec
| Reddit |
keep SSH-port-forwarding connection alive. <p>I am doing a permanent port forwarding via SSH. It is basically</p>
<pre><code>while true; do
ssh <somewhere> \
-R <dst-port>:localhost:<src-port> \
-N -n -o ExitOnForwardFailure=yes
sleep 10
done
</code></pre>
<p>However, that is not very reliable. Sometimes, the port is not forwarded at all (I'm not sure if the connection is correctly alive but I can see the process on the client and it is running already for several hours), sometimes the connection is surely not alive anymore (because the network interface is down) but it takes very long (sometimes up to 30-60 minutes) to timeout.</p>
<p>How can I make that more reliable? I want to have a timeout of maybe a minute.</p>
<hr>
<p>I just found <a href="https://superuser.com/questions/111005/stable-reverse-port-forwarding-in-ssh-and-stale-sessions">this very related/similar question</a>. However, the first answer indicates that <code>ExitOnForwardFailure</code> should solve it but I already have that and it does not (I can see right now the running <code>ssh</code> process with this option but the port is not forwarded).</p>
| 0non-cybersec
| Stackexchange |
Possible to retrieve an arbitrary unordered set of named groups in one swoop with Python's re module?. <p>This is super handy for some problems:</p>
<pre><code>>>> re.search('(?P<b>.b.).*(?P<i>.i.)', 'abcdefghijk').groupdict()
{'i': 'hij', 'b': 'abc'}
</code></pre>
<p>But what if I don't know what order to expect ahead of time? </p>
<p>[update]</p>
<p>Eg, say I have an input variable containing some unknown order of characters and it just so happens that 'b' comes after 'i'. I want to still be able to reference the groups for '.b.' and '.i.' without having to order my regex according to their order in the input var. So, I wish I could do something like this but I don't know if it's possible:</p>
<pre><code>>>> re.search('(?P<b>.b.)|(?P<i>.i.)', unknown_order_alphabet_str).groupdict()
{'i': 'hij', 'b': 'abc'}
</code></pre>
<p>[end update]</p>
<p>I've searched around and racked my brain a bunch but can't generate any good leads. Guessing this functionality wouldn't exist because probably the only way for re to do this is to scan the entire string once for each group (which of course I could do in a loop instead) but I thought I'd see what the stackoverflow brain had to say about it.</p>
<p>Thanks for your help,<br>
Josh</p>
| 0non-cybersec
| Stackexchange |
http://www.healthyminimag.com/skin-opulent-reviews/. | 0non-cybersec
| Reddit |
Sphinx: New Zeus Variant for Sale on the Black Market. | 1cybersec
| Reddit |
Acoustic cover of "Baby Got Back," performed by Derek Kurth - Hilarious and surprisingly beautiful.. | 0non-cybersec
| Reddit |
Copycat Garlic Butter Breadsticks. | 0non-cybersec
| Reddit |
I want to code a condition $p=(s,D)$ where $s\in\omega^{<\omega}$ and $D\subseteq [\omega^\omega]^{<\omega}$ by real in $\omega^\omega$.. <p>How can we define a function $F:\omega^{<\omega}\times[\omega^\omega]^{<\omega}\to \omega^\omega$ ? where $[\omega^\omega]^{<\omega}=\{D\subseteq \omega^\omega: |D|<\aleph_{0}\}$ and $\omega^{<\omega}=\bigcup_{n<\omega}\omega^{n}$.</p>
<p>I want to code a condition $p=(s,D)$ where $s\in\omega^{<\omega}$ and $D\subseteq [\omega^\omega]^{<\omega}$ by real in $\omega^\omega$.</p>
| 0non-cybersec
| Stackexchange |
Commerce Police Chief Resigns Over Unjustly Detaining and Arresting Woman In Walmart Over Personal Dispute (video Inside). | 0non-cybersec
| Reddit |
Intel 82579V LAN driver dropping out. <p>My PC has an Intel 82579V Gigabit Network Connection and the on-board LAN adapter has started misbehaving over the last few days. When I boot up, the PC has no LAN connection. The entry in device manager shows an error (yellow triangle).</p>
<p>If I uninstall the driver and restart (warm boot), it works properly until I close down, but next time I boot up, the problem occurs again. I've gone round this cycle over several days and it's consistent. The network never drops once operating correctly, and since I had this problem, has never worked after a cold boot.</p>
<p>When this first happened, it was using a 2012 driver, so I downloaded the latest driver from Intel's site - it's recent, the package is dated July 12 2015 - and installed that. It made no difference. The driver extracted automatically from the package is dated May 2 2014.</p>
<p>I'm running Windows 7 Ultimate, 64-bit, fully up to date. The machine is a couple of years old and has performed well up to now.</p>
<p>Any suggestions about what might cause powering down to make the LAN adapter lose its grip on the driver like this?</p>
<p>Thanks.</p>
<p><strong>Update: Aug 3, 2015</strong> - I found that I don't have to uninstall the driver. Just doing a warm boot after a cold one gets the LAN connection working properly.</p>
<p><strong>Conclusion: Jan 6, 2016</strong> - A satisfactory conclusion for me, but an unsatisfying end to this question because I can't give an answer that has any useful information: This problem went away after several months of it happening after every cold boot. I had given up trying to change boot settings and did nothing I'm aware of to fix the problem.</p>
| 0non-cybersec
| Stackexchange |
Laptop fan makes grinding noise: needs replacement? (video). <p>Over the last days, my laptop's fan is making a constant grinding noise all the time, as soon as it starts to spin, except maybe for the first minute or two after turning my laptop on. It's a constant, loud noise and can be heard in this video:</p>
<p><a href="https://drive.google.com/file/d/0BwjYARtEfuKgczlOQ3FXZGJabGM/view" rel="nofollow noreferrer">https://drive.google.com/file/d/0BwjYARtEfuKgczlOQ3FXZGJabGM/view</a></p>
<p>Initially, I had suspected it was a dust issue, so I disassembled my laptop to clean the fan and found it in the following state:</p>
<p><a href="https://i.stack.imgur.com/PznUM.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/PznUM.jpg" alt="Fan before dust cleaning"></a></p>
<p>Nevertheless, the noise did not go away after that, as it's evident from the video.</p>
<p>I am very confident in replacing laptop hardware parts, but I have zero experience with fans. Is this grinding noise indicating my fan needs replacement? Would you recommend any hardware/software checks beforehand? (Debian Testing user, if that matters)</p>
<p>If my fan does need replacement, which is the correct process of doing so? For the RAM I would find a similar type and frequency, for example; what would I look for, in this case? Do I also have to disassemble the whole heat sinker that the fan is connected to? (see picture below)</p>
<p><a href="https://i.stack.imgur.com/9lEGf.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/9lEGf.jpg" alt="Motherboard (before cleaning)"></a></p>
| 0non-cybersec
| Stackexchange |
use netcat to create any kind of connection you need .. | 1cybersec
| Reddit |
Have you ever known such a madlad?. | 0non-cybersec
| Reddit |
Dovecot/Postfix mail server replies to [SYN] with [RST, ACK] when user attempts to connect (POP3). Likely iptables?. <p>Currently I am trying to trouble shoot an e-mail server that will allow users to send e-mail, but not log in to the server (POP3) or receive e-mail using their Outlook clients. Previously this was doable, but moving the server to it's current location broke it. For obvious reasons, I suspect it's the firewall causing issues.</p>
<p>Firstly, here is what the handshake (or attempt at) looked like before I made any changes to the firewall:</p>
<p><strong>mail-server</strong>: 192.168.25.26
<strong>client</strong>: 192.168.25.50</p>
<pre><code> Source | Destination | PROTO | INFO
192.168.25.50 192.168.25.26 TCP 50861 > pop3 [SYN] seq=0 win=65535 len=0
192.168.25.26 192.168.25.50 TCP pop3 > 58601 [RST, ACK] seq=1 win=1 len=0
192.168.25.50 192.168.25.26 TCP [TCP Retransmission] 58061 > pop3 [Syn] etc....
</code></pre>
<p>and the [rst, ack], [tcp retransmission] dance happens once more before failing. </p>
<p>The rules for the firewall (Cisco) concerning 192.168.25.26 and pop3 are as follows:</p>
<p>inside:</p>
<pre><code> source | destination | service
any 192.168.25.0/24 tcp/pop3
192.168.25.0/24 any tcp/smtp
208.105.121.196
</code></pre>
<p>outside:</p>
<pre><code> source | destination | service
any 192.168.25.26 tcp/pop3
any tcp/smtp
</code></pre>
<p>To me, that looks fine. </p>
<p>To be certain, on the email server (Zentyal) I ran the following commands:</p>
<p>(IP tables was HEAVILY configured. I suspect the issue lies here. Is there any way to allow <strong>all</strong> traffic, just for testing's sake?)</p>
<pre><code>sudo iptables -F
sudo iptables -P INPUT ACCEPT
sudo iptables -P FORWARD ACCEPT
sudo iptables -P OUTPUT ACCEPT
</code></pre>
<p>However, there's still no outlook connectability. At this point, on the email server I ran the command:</p>
<pre><code>telnet 127.0.0.1 110
</code></pre>
<p>and was able to log in to the mail server. From a client inside the network, I ran the same command and was told the "connection failed".</p>
<p>After these changes, when I attempt to "test the settings" in Outlook, here's what the handshake looks like. I noticed something peculiar.</p>
<pre><code> Source | Destination | PROTO | INFO
192.168.25.50 192.168.25.26 TCP apollo-status > pop3 [SYN] seq=0 win=65535 len=0
192.168.25.26 192.168.25.50 TCP pop3 > apollo-status [RST, ACK] seq=1 win=1 len=0
192.168.25.50 192.168.25.26 TCP [TCP Retransmission] apollo-status > pop3 [Syn] etc....
</code></pre>
<p>and it does it twice more, like the last time. In the INFO pane, I now see apollo-status instead of a port number. The next two times I ran it, I saw npep_messaging and synapse, respectively. I suspect these are random ports chosen by dovecot, because in dovecot.config I changed the default listener to an asterisk "*" from the port previously specified, which seemed to be an arbitrary port in the 4,000's and had no rules in the firewall.</p>
<p>Just to confirm, it seems the port it uses each time is changing based on the (recommended) configuration. On the loopback interface port 110 clearly has a listener attatched to it, but from another computer, it appears to be closed.</p>
<p>Any help <em>at all</em> is appreciated. I've racked my brain with this, and I'm hoping the serverfault community will have some novel ideas.</p>
<p>Thank you!</p>
| 0non-cybersec
| Stackexchange |
My child is a little over two years old and after playing at the park she has really bad body odor. Is this normal for a child so young?. Hi guys, thanks for taking the time to answer my question. I don't have much more to add other then what's included in the title but I'll make edits to provide more information if necessary.
Edit: To clarify she smells like a man would after working out without deodorant. I hope I can nip this problem in the bud; I'd hate for her to grow up being known as the smelly girl :( | 0non-cybersec
| Reddit |
What are some common AWS Lamdba (specific) Security Pitfalls, Auditing Tools, and Methods of Mitigation?. <p>I am writing a research paper detailing the security vulnerabilities of serverless AWS lambda applications, and how to prevent them. I am also compiling a list of security auditing tools that are designed to target serverless lambda applications. </p>
<p>I am trying to compile an exhaustive list of known lambda specific vulnerabilities, common mistakes (such as AWS lax permission policies), and how to prevent or mitigate against them. So far I have:</p>
<ul>
<li><p>Remote command injection is possible, particularly if data is not sanitized correctly. </p></li>
<li><p>Leaked AWS credentials also obviously affect lambda as well, this is a very common mistake (such as credentials stashed in git commits, as demonstrated on <a href="http://flaws.clould" rel="nofollow noreferrer">flaws.cloud</a>)</p></li>
<li><p>API Gateway is always publicly accessible, so we need to take the necessary precautions to secure access to our internal APIs, preferably with IAM roles. </p></li>
<li><p>Lambda costs incurred during a DoS attack ("cost attacks")</p></li>
<li>Functions often are given more permissions than necessary which can lead to compromise</li>
<li>Unused functions accidentally, or lazily left around can turn into attack surfaces.</li>
<li>From <a href="https://rhinosecuritylabs.com/aws/aws-privilege-escalation-methods-mitigation/" rel="nofollow noreferrer">rhino security labs aws writeup:</a>
<ul>
<li>It is possible to pass a new role to a lambda function and then invoke it.</li>
<li>It is possible to pass a role to a new Lambda function and trigger it with DynamoDB</li>
<li>It is possible to modify the code of an existing lambda function and exploit it</li>
</ul></li>
</ul>
<p>For tools used to audit AWS, so far I have found quite a few:</p>
<ul>
<li><a href="https://github.com/RhinoSecurityLabs/Security-Research/tree/master/tools/aws-pentest-tools" rel="nofollow noreferrer">Aws-Pentest-Tools by Rhino Security Labs</a></li>
<li><a href="https://github.com/toniblyx/my-arsenal-of-aws-security-tools" rel="nofollow noreferrer">AWS 'Arsenal of Tools' by toniblyx</a></li>
</ul>
<p>I am trying to make the list if known Lambda-specific vulnerabilities & common mistakes as exhaustive as possible. Personally I am not terribly experienced with AWS or Lambda, so I wanted to ask those of you in the security community that have real world experience deploying, maintaining, and/or auditing Lambda applications:</p>
<ul>
<li><p>What are the most common mistakes that administrators make when deploying lambda applications, and how can they be prevented?</p></li>
<li><p>What are some common vulnerabilities specifically having to do with lambda instances running Python code, and how can they be avoided? (Interested to hear about other languages as well)</p></li>
<li><p>Has anyone with experience administering lambda encountered a scenario involving any of the vulnerabilities on my list? I would love to hear your story. </p></li>
<li><p>What else should I add to these lists?</p></li>
</ul>
<p>Essentially I am asking for help making these lists as exhaustive as possible; particular the list of vulnerabilities. <em>Real world experience and examples would be much appreciated.</em> The main question is: What am I missing?</p>
| 1cybersec
| Stackexchange |
Following migration (Server 2003 to 2008), File Services is SLOW; any idea why?. <p>Okay - the run-down:</p>
<p>INITIAL INSTALL</p>
<ul>
<li>Brought a new Dell rack-mount server up, running Server 2008 Standard x64.</li>
<li>All Windows updates, File Services role added; everything completed without issue. Installed FS using 2003 and indexing option, not Windows Search Services.</li>
<li>Installed Symantec Endpoint Protection 11.0.6000.645 (AV only - no NTP or email or anything).</li>
<li>Robocopied all existing shares from the server (running 2003) and verified them on the 2008 rig (no issues).</li>
<li>Deallocated and switched off the 2003 server; renamed the 2008 server to the 2003 server's former network name.</li>
</ul>
<p>Shortly after migration, users complained of epic slowness. I changed the 2008 server to use WSS instead of 2003/indexing, restarting afterward. Still no joy. I've worked at it all week, trying different options out on the Internet-at-large.</p>
<p>THINGS I'VE TRIED (to no avail)</p>
<ul>
<li>Disabling SMB 2.0 on the server, leaving 1.0 active.</li>
<li>Disabling SMB 1.0 on the server, leaving 2.0 active.</li>
<li>Disabling SMB on the server, leaving neither version active (NetBIOS only, I guess?).</li>
<li>Updating SEP to latest (11.0.7000.975).</li>
<li>Uninstalling SEP altogether.</li>
<li>Enabling/disabling IPv6 binding.</li>
<li>Disabling TCP Offload at the NIC (both IPv4 and IPv6)</li>
<li>Pretty much anything I found while hunting the Internets for solutionbeasts.</li>
</ul>
<p>We have a mixed bag of clients, mostly XP, with some Win7 thrown in (all standard versions, pretty sure all are x86). I can open everything without issue, both from my Win7 (x86) laptop (my standard work machine) and from my XP VM x86 test machine (out on an ESX server). The only difference I can find (that seems like it would matter) is that my stuff is all on one subnet, while the other client machines are on another (x.x.1.x versus x.x.2.x).</p>
<p>I don't understand where the slowness comes from. Certainly, the 2003 server didn't have this problem or the users would've already complained. Any ideas or direction from the one community I trust to actually solve problems would be awesome.</p>
<p>And - I'll apologize in advance if there's actually a thread somewhere that answers just this issue; I just couldn't find it (but not for lack of trying). Thanks, in advance, all.</p>
| 0non-cybersec
| Stackexchange |
pgfplots: how to use "index of colormap" to specify a color?. <p>The MWE below uses the <code>pgfplots</code> function <code>index of colormap</code> to specify the color of a drawn path. However if I uncomment the second <code>\draw</code> command which explicitly uses the <code>color=</code> key, I get <code>Package xcolor Error: Undefined color `index of colormap={0 of hot}'</code> The commented <code>\shade</code> command is closer to what I really want to do, namely to use colormap colors in a shade command, where really I have to use the <code>key=value</code> syntax.</p>
<pre><code>\documentclass{article}
\pagestyle{empty}
\usepackage{tikz}
\usepackage{pgfplots}
\pgfplotsset{compat=1.16}
\begin{document}
\begin{tikzpicture}
\begin{axis}[xmin=-2,xmax=2,ymin=-2,ymax=2]
\draw[index of colormap={0 of hot}] (-2,1.5) -- (2,1.5);
%\draw[color={index of colormap={0 of hot}}] (-2,1) -- (2,1);
%\shade[left color={index of colormap={0 of hot}},right color={index of colormap={1 of hot}}] (-2,-2) rectangle (2,0);
\end{axis}
\end{tikzpicture}
\end{document}
</code></pre>
| 0non-cybersec
| Stackexchange |
EnumDataType() attribute validation error message not displaying. <p>In my .net core 2.0 Web API I am using EnumDataType() validation attribute on my model property. When the validation fails the custom error message is empty. I am not sure why it is happening - </p>
<pre><code>EnumDataType(typeof(MyEnum), ErrorMessage = "Custom Error Message")
public MyEnum MyEnumProp {get; set;}
</code></pre>
<p>I checked the other properties where I have [Required], [MinLength] and all are generating custom error messages. Am I doing something wrong? Is there any other approach?</p>
| 0non-cybersec
| Stackexchange |
How can I make notifications larger, so less text is cropped?. <p>I am using Monotony to see news headlines as notifications. I have set it to "Alert style" so they are slightly larger and stay there until I click them. However I would like the notifications to be a bit larger so that less text is cropped. Right now too much is cropped to even read a headline.</p>
<p>Is this possible, either through the default notification system or by installing some other notification system?</p>
<p>Following screenshot shows that a typical headline and article summary are not readable:</p>
<p><a href="https://i.stack.imgur.com/EFUPD.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/EFUPD.png" alt="enter image description here"></a></p>
| 0non-cybersec
| Stackexchange |
NOVA - The Bible's Buried Secrets. I highly recommend this documentary. It points out many of the Bible's falsehoods, based on archeological fact.. | 0non-cybersec
| Reddit |
How to be certain "cp -n -r /dir/ /des/" does not overwrite files.. and is doing its job ? verbose mode?. <p>I run the command</p>
<pre><code> cp -n -r /dir/ /backup/
</code></pre>
<p>but there is no way to tell what it is doing.. <br>
if it is skipping files that already exists..</p>
<p>if it is doing anything..</p>
<p>I tried adding </p>
<pre><code>-v
</code></pre>
<p>option to it.. still no data.. on what it is doing..</p>
| 0non-cybersec
| Stackexchange |
Errors in the RingCT 3.0 paper. <p>I found some errors in the RingCT 3.0 paper (<a href="https://eprint.iacr.org/2019/508.pdf" rel="nofollow noreferrer">https://eprint.iacr.org/2019/508.pdf</a>) in the ring signature chapter.
This makes it impossible to implement this algorithm.</p>
<p>Namely:</p>
<ol>
<li><p>In the chapter “<em>C.2 Ring Signature with Logarithm Size</em>”/”<em>Challenge 2</em>” was defined:
<code>x = H5(v, w, y, z, T1, T2, m)</code>
At that, the variable <strong>v</strong> is not defined anywhere else in the text.</p></li>
<li><p>In the chapter “<em>C.2 Ring Signature with Logarithm Size</em>”/”<em>Challenge 1</em>” was defined:
<code>str′ = Y ||B||A|| S1||S2||U</code>
At that, the variable <strong>U</strong> also is not defined anywhere else in the text.</p></li>
</ol>
<p>Perhaps someone can clarify the situation.</p>
| 0non-cybersec
| Stackexchange |
Java EE Fundamentals. <p>I've read the wikipedia articles. I've browsed the Oracle tutorials. I've Googled, binged and Yahooed, and still, I am choking on the most basic fundamentals of Java EE (5+).</p>
<ol>
<li><p>Must all Java EE architectures involve an application server, such as JBoss or GlassFish, at some point? Essentially, is the concept of the application server fundamental to Java EE, and why/why not?</p></li>
<li><p>Beyond application servers, are there any other major components that a Java EE architecture depends on? If so, what are they and how do they "snap into" the architecture and relate to the application server?</p></li>
<li><p>I'm really choking on the concept of EJBs. From <em>everything</em> I've been able to find on them, I can't tell if EJB is a <em>specification</em> for developers to use (whereby complying with the EJB spec produces a unit of code that can be called a "bean"), or if its like any other Java library, like <strong>JDBC</strong> or <strong>JMS</strong>.<p>
(a) In the King's English, without using advanced, already-in-the-know concepts or marketing buzzwords, what is EJB? Can you provide a few quick & dirty examples of (an) EJB?<p>
(b) How does EJB interface/interact with an application server?<p>
(c) What is an EJB "container", and what does it do?</p></li>
<li><p>It seems to me like there are a lot of top-level components that make up a Java EE backend, and that for
each type of these components, there are <em>a lot</em> of both open- and closed-source varieties out there that
you, the system engineer, must choose from.<p>
Seeing that I am so confused on Java EE fundamental already, below is a list of some products I have heard
about. I am simply asking for someone to help me categorize these products so I can see, in plain sight,
what they are. For instance, if I list "GlassFish" and "JBoss", then they might appear in the category of
"Application Servers." If I list "Tomcat" and "WebSphere", they might appear under "Servlet Engines", etc.<p>
The list:<ul>
<li>JBoss</li>
<li>Geronimo</li>
<li>Jetty</li>
<li>GlassFish</li>
<li>Tomcat</li>
<li>Spring RabbitMQ</li>
<li>Spring GemFire</li>
<li>Spring ers</li>
<li>Spring tc Server</li>
<li>Hibernate</li>
</ul></p></li>
</ol>
<p><p>
5. What's the difference between Java EE 6 and Java EE 6 "Web Profile"?</p>
| 0non-cybersec
| Stackexchange |
Debian Wheezy 7.7.0 x86 - won't compile anything. <p>Yesterday I installed Debian Wheezy 7.7.00-netinst and everything was fine until the moment I decided to compile libtorrent-0.13.4.
I do:</p>
<pre><code>./configure
</code></pre>
<p>the checkings start for about 2 seconds and the whole system just resets (it's headless, but I attached a monitor and the screen first goes gray and then I see the BIOS POST)..
Then I tried to compile wget, curl and again, with the same results.</p>
<p>After that I decided to try to push the system to its limits </p>
<pre><code>stress -c 3 -m 1200M
</code></pre>
<p>for about 15 minutes and nothing happened other than the system get a little hot.</p>
<p>Today, I reinstalled the whole system and installed Debian Wheezy 7.7.00-CD 1.
Again, the same thing happens.</p>
| 0non-cybersec
| Stackexchange |
AWS forward request between private instances. <p>I have a public subnet holding AWS ELB which forward its requests to a private EC2 instance.</p>
<p>Is there a way I can forward the request from my private EC2 request to another private EC2 instance?</p>
<p>In public instance i used .htaccess with RewriteRules, and I would be happy to use it now, but I don't know how to forward requests privately.</p>
| 0non-cybersec
| Stackexchange |
Can I use in a non-free script a code example that doesn't mention license but which is used by its author in a GPL'ed script?. <p>After seeing the following <a href="https://softwareengineering.stackexchange.com/questions/81705/rewriting-gpl-code-to-change-license">question</a> one of my problems came in mind: I want to couple two different scripts in two different languages.</p>
<p>I found a solution for that, and I copied that solution. Unfortunately the same author uses this code for a script which he put under the GPL, but he did not mention the GPL in his example.</p>
<p>Can I use the connection (pipe-construction) in a non-free script, even if the script he uses this code is under the GPL?</p>
<p>I want to combine python and ruby, and I used the code from this <a href="http://www.decalage.info/en/python/ruby_bridge" rel="nofollow noreferrer">page</a>. Later I found out that he wrote a script licensed under the GPL using the same technique.</p>
| 0non-cybersec
| Stackexchange |
How to modify grid-template-areas with javascript. <p>I have been trying to modify <code>grid-template-areas</code> with javascript. I found a property in the css properties list (<code>elem.style</code>) in the DOM called: <code>gridTemplateAreas</code>. But I seem to be unable to change it with javascript.</p>
<p>How do i modify the <code>grid-template-areas</code>-property with javascript?</p>
<p>Here is the code I tried:</p>
<p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
<div class="snippet-code">
<pre class="snippet-code-js lang-js prettyprint-override"><code>window.addEventListener("click", function(){
let elem= document.getElementById("grid");
elem.style.gridTemplateAreas =
"z z z"
"a b c"
"d e f"
console.log("The grid-template area should have been redefined now. The blue block should have move to the top row.");
});</code></pre>
<pre class="snippet-code-css lang-css prettyprint-override"><code>#grid{
width: 100px;
height: 100px;
background-color: red;
display: grid;
grid-template-columns: 1fr 1fr 1fr;
grid-template-rows: 1fr 1fr 1fr;
grid-template-areas: "x x x"
"y y z"
"y y z";
}
#div1{
background-color: blue;
grid-area: z;
}</code></pre>
<pre class="snippet-code-html lang-html prettyprint-override"><code><h3>Click to activate the code</h3>
<div id="grid">
<div id="div1"></div>
</div></code></pre>
</div>
</div>
</p>
<p>PS: I am using Google Chrome a.t.m.</p>
| 0non-cybersec
| Stackexchange |
Asynchronously populating a Java Map and returning it as a future. <p>I've got a map of objects which are expensive to create, and so I want to create the objects and fill the map in parallel with other processes in my application. Only when the main thread actually needs to access the map should the application wait for the asynchronous task(s) populating the map to finish. How can I most elegantly accomplish this?</p>
<h2>Current approach</h2>
<p>Currently, I am able to create each individual object in the map itself asynchronously using <a href="https://docs.oracle.com/javase/8/docs/api/java/util/concurrent/CompletableFuture.html#runAsync-java.lang.Runnable-java.util.concurrent.Executor-" rel="noreferrer"><code>CompletableFuture.runAsync(Runnable, Executor)</code></a> analogously to in the example code below, but I'm unsure of how I can build a <code>Future</code>/<code>CompletableFuture</code>-type mechanism for returning the <code>Map</code> itself when ready:</p>
<pre><code>public static class AsynchronousMapPopulator {
private final Executor backgroundJobExecutor;
public AsynchronousMapPopulator(final Executor backgroundJobExecutor) {
this.backgroundJobExecutor = backgroundJobExecutor;
}
public ConcurrentMap<String, Integer> apply(final Map<String,Integer> input) {
final ConcurrentMap<String, Integer> result = new ConcurrentHashMap<>(input.size());
final Stream.Builder<CompletableFuture<Void>> incrementingJobs = Stream.builder();
for (final Entry<String, Integer> entry : input.entrySet()) {
final String className = entry.getKey();
final Integer oldValue = entry.getValue();
final CompletableFuture<Void> incrementingJob = CompletableFuture.runAsync(() -> {
result.put(className, oldValue + 1);
}, backgroundJobExecutor);
incrementingJobs.add(incrementingJob);
}
// TODO: This blocks until the training is done; Instead, return a
// future to the caller somehow
CompletableFuture.allOf(incrementingJobs.build().toArray(CompletableFuture[]::new)).join();
return result;
}
}
</code></pre>
<p>However, with the code above, when code calls <code>AsynchronousTest.create(Map<String,Integer)</code>, it already blocks until the method returns the entirely-populated <code>ConcurrentMap<String,Integer></code>; How can I turn this into something like a <code>Future<Map<String,Integer>></code> so that I can use it at a later time?:</p>
<pre><code>Executor someExecutor = ForkJoinPool.commonPool();
Future<Map<String,Integer>> futureClassModels = new AsynchronousMapPopulator(someExecutor).apply(wordClassObservations);
...
// Do lots of other stuff
...
Map<String,Integer> completedModels = futureClassModels.get();
</code></pre>
| 0non-cybersec
| Stackexchange |
[Image] From the end of a Minimalism documentary that hit me way too hard.. | 0non-cybersec
| Reddit |
New Tattoo!!! (If you wanna see it healed I can post an updated pic in a few weeks). | 0non-cybersec
| Reddit |
How to prevent eyestrain?. <p>For the following months, i'm going to work at home and will spend most of my time in front of my computer.
Currently, i work on my computer more than 8 hours a day. (10h-14h on screens daily) </p>
<p>I've got a 15.6 inch laptop and a 23 inch screen on my PC. Except getting dark themes on editors and randomly lower brightness, i don't have any big clues to avoid eyes fatigue.</p>
<p>Just asking you guys, if you got couple of tips to avoid me future headaches !! </p>
<p>PS :
-i'm wearing glasses for Myopia-Astigmatism.
-sorry if my english is bad</p>
| 0non-cybersec
| Stackexchange |
Linking Correlated Network Flows through Packet
Timing: a Game-Theoretic Approach
Juan A. Elices
University of New Mexico
Email: [email protected]
Fernando Pérez-González
Universidad de Vigo
Email: [email protected]
Abstract—Deciding that two network flows are essentially the
same is an important problem in intrusion detection or in tracing
anonymous connections. A stepping stone or an anonymity
network may try to prevent flow correlation by delaying the
packets, introducing chaff traffic, or even splitting the flow in
several subflows.
We introduce a game-theoretic framework for this problem.
The framework is used to derive the Nash equilibrium under two
different adversary models: the first one, when the adversary is
limited to delaying packets, and the second, when the adversary
also adds dummy packets and removes packets from the flow. As
the optimal decoder is not computationally feasible, we restrict
the possible decoder to one that estimates and compensates the
attack. Our analysis can be used for understanding the limits of
flow correlation based on packet timings under an active attacker.
Index Terms—traffic analysis, game theory, flow watermark,
network security
I. INTRODUCTION
Network attackers intentionally hide their identity to avoid
prosecution. A broadly-used way of achieving this anonymity
is relaying the traffic through a chain of compromised hosts
called stepping stones [1]. Intrusion detection and tracing
back an attack require deciding that two flows are correlated.
Linking network flows can also be used to compromise low-
latency anonymous networks, such as Tor.
Two approaches exist for finding correlated flows: passive
analysis and active watermarks. They differ in whether the
flow is modified or not. In general, an active watermark needs
shorter sequences but at the expense of being detectable [2].
An adversary (AD), for instance a stepping stone or an
anonymous network, may take countermeasures to prevent the
correlation such as introducing delays to packets or adding
dummy packets to the flow, or even more drastic measures, e.g.
dividing the flow into different subflows each taking different
paths. To the best of our knowledge, in previous works, only
[3] and [4] consider an AD, and in both the AD is limited to
delaying packets.
This paper studies the limits of traffic analysis, passive
or active, in an adversarial environment. The most natural
solution to avoid the loop of proposing an attack and creating
an ad-hoc solution is to cast the problem into a game-
theoretic framework and look for the optimum strategies that
the players, traffic analyst (TA) and AD, should adopt. A
game-theoretic framework similar to the proposed one has
been used in other contexts such as Information Hiding [5]
or Source Identification [6].
The rest of the paper is organized as follows: in Section II
we introduce the notation, together with some basic concepts
of game theory. Section III presents a rigorous denition of the
traffic analysis game. Section IV solves the problem under an
AD model that only introduces delays. Section V deals with
a stronger AD problem that also adds chaff traffic and divides
the flow. Conclusions are presented in Section VI.
II. NOTATION AND BASIC CONCEPTS
We use the following notation. Random variables are de-
noted by capital letters (e.g., X), and their individual realiza-
tions by lower case letters (e.g., x). The domains over which
random variables are defined are denoted by script letters (e.g.,
X ). Sequences of n random variables are denoted with Xn if
they have random nature or by xn if they are deterministic. Xi
or xi indicate the ith element of Xn or xn, respectively. The
probability distribution function (pdf) of a random variable
X is denoted by fX(x), x ∈ X . We use the same notation
to refer to pdf of sequences, i.e. fXn(xn), xn ∈ Xn. When
no confusion is possible, we drop the subscript in order
to simplify the notation. We denote with ∆ the difference
operation of a sequence, i.e ∆xn = {x2−x1, . . . , xn−xn−1}
and with ∆xi = xi+1 − xi the ith element of this sequence.
A. Game Theory
Game theory is the mathematical study of interaction among
independent, self-interested agents. Formally, a two-player
game is defined as a quadruple G(A1, A2, u1, u2), where
Ai = {ai,1, . . . ai,ni} are the actions available to the ith player,
and ui : A1 × A2 7→ R, i = 1, 2 is the utility function
or payoff of the game for player i. An action profile is the
double a ∈ A1 × A2. We are interested in zero-sum games,
where u1(a) + u2(a) = 0,∀a ∈ A1 × A2, which means that
the gain (or loss) of utility of player 1 is exactly balanced by
the losses (or gains) of the utility of player 2. In this case,
we can simplify the game notation to a triplet G(A1, A2, u),
where u = u1 = −u2.
We say that an action profile (a1,i∗ ; a2,j∗) represents a Nash
equilibrium (NE) if u(a1,i∗ ; a2,j∗) ≥ u(a1,i; a2,j∗) ∀a1,i ∈
A1 and u(a1,i∗ ; a2,j∗) ≤ u(a1,i∗ ; a2,j) ∀a2,j ∈ A2, intu-
itively, this means that none of the players can improve its
ar
X
iv
:1
30
7.
31
36
v1
[
cs
.C
R
]
1
1
Ju
l
20
13
AD
TA
Detector
TA
Fingerprinter
Fig. 1: Model of the TAG game
utility by modifying his strategy assuming the other player
does not change his own.
Games can be classified in simultaneous games, where
both players move unaware of the other player action, and
sequential games, where later players have some knowledge
about earlier actions. In sequential games an action profile is
a subgame perfect equilibrium (SPE) if it represents a NE of
every subgame of the original game. Therefore, a SPE is a
refinement of the NE that eliminates non-credible threats.
III. TRAFFIC ANALYSIS GAME
The Traffic Analysis game (TAG) is represented in Figure 1.
In this game, there are two players: TA and AD.
The task of the TA is to create a test to accept or reject
the hypothesis that a flow wm is indeed the same flow as a
known one, xn, that can be the original flow (passive traffic
analysis) or the output of a watermarker. In this paper we
do not consider the problem of how to create the watermark.
Furthermore, all the simulations are done in a passive analysis
situation.
On the other side, the goal of the AD is to modify the
flow in such a way that the TA decides that this sequence is
not a modified version of xn. In order to do this, AD can
delay any packet at most Amax seconds. We denote by an the
sequence of delays added by AD. In Section V, we propose
a more powerful attacker model that can add up to PA · n
dummy packets and remove PL · n packets, assuming they
are sent through a different path, hence PA is the maximum
ratio between chaff traffic and original traffic and PL is the
maximum probability of a packet being removed.
As shown in Figure 1 the flow suffers two additional delays
Dn1 and D
m
2 that are due to the network between where x
n is
measured (TA-1) and AD, and between AD and where wm is
measured (TA-2), respectively. We represent by D the delay
that suffers a packet from TA-1 to TA-2, i.e. D = D1 + D2.
Note that ∆D is the packet delay variation (PDV), also called
jitter.
Let Y m represent flows without any relation to xn, but from
the same application. We assume that f∆Y (∆y) is known by
both players, and define the hypotheses: H0: wm is not a
modified version of xn, and H1: wm is a modified version
of xn.
We define the TAG game as follows:
Definition 1. The TAG(ATA;AAD;u) is a simultaneous,
zero-sum game played by the FA and the AD, where
• The set of actions the FA can choose from, i.e. ATA,
is the set of acceptance regions for H1 for which the
probability of false positive (i.e., accepting H1 when H0
is true) is below a certain threshold η. Note that the
acceptance region can be different for each sequence.
Therefore, ATA = {Λ1(xn) : Pr(ym ∈ Λ1(xn)) < η}.
• The set of possible attacks that the AD can choose from,
i.e. AAD. It depends on the assumed adversary model.
• The utility function is the probability of detec-
tion, (i.e., accepting H1 when H1 is true), namely:
u(Λ1(x
n), AAD) = Pr(w
m|H1 ∈ Λ1(xn)).
As the TA can choose its action Λ1(xn) after knowing wn,
the solution to the game is
u = min
AAD
max
ATA
u(ATA, AAD). (1)
IV. DELAYING ADVERSARY MODEL
This section derives the detector under an AD that is
limited to delaying the packets constrained to Amax seconds.
Under this condition, there exists a one-to-one correspondence
between xn and wm, consequently m = n.
We confine the detector to those based on first-order statis-
tics of the inter-packet delay (IPD), i.e., ∆x and ∆w, for fea-
sibility reasons. Among those, the FA constructs the optimal
detector which, according to Neyman-Pearson Lemma, is the
likelihood ratio test
ΛAD(w
n, xn, f
Ân|Xn) =
`(H1|∆wn,∆xn)
`(H0|∆wn,∆xn)
=
n−1∑
i=1
log
(∫∫
Â2
f∆D(∆ri −∆âi)fÂi,i+1|Xi,i+1(âi, âi+1|xi,i+1)
f∆Y (∆wi)
dâidâi+1
)
,
(2)
where rn is wn−xn, ` represents the log-likelihood function,
and f
Ân
the estimated joint pdf for An. Hence, the test
chooses H1 when ΛAD(wn, xn, fÂn|Xn) ≥ � where � is a
threshold that we fix to achieve a certain probability of false
positive. In this case, the TA actions are all the possible
joint pdfs for Ân given xn, i.e. ATA = fÂn|Xn(a
n|xn).
Unfortunately, calculating the joint pdf that maximizes ΛAD
is a computationally intractable problem.
Therefore, we restrict the detector, at the expense of losing
the optimality, to one that estimates the sequence ân instead
of its joint pdf. In this case, the likelihood ratio test is
ΛAD(w
n, xn, ân) =
n−1∑
i=1
log
(
f∆D(∆i(r
n − ân))
f∆Y (∆iwn)
)
, (3)
and the TAG game is modified as follows:
ATA = {ân : ∀i ∈ [0, n], 0 ≤ âi ≤ Amax } (4)
AAD = {an : ∀i ∈ [0, n], 0 ≤ ai ≤ Amax} (5)
u(ân, an) = Pr(ΛAD(x
n + an +Dn, xn, ân) > �), (6)
where Pr(ΛAD(Y
n, xn, ân) ≤ �) = η. (7)
From (1), we obtain the solution to the game
ATA = arg max
â
ΛAD(w
n, xn, ân) (8)
AAD = arg min
an
Pr(max
ân
ΛAD(x
n + an +Dn, xn, ân) > �).
(9)
As the AD must decide its action in real time and (9) is
computationally expensive, we approximate it by
AAD ≈ arg min
an
n−1∑
i=1
log f∆Y (∆xi + ∆ai). (10)
which is a good approximation when ∆D has zero-mean
and its variance is much smaller than ∆Y (as it is the
case in practice). Note that under this approximation AD is
maximizing the likelihood of xn + an coming from yn, i.e.,
making the sequence as typical as possible.
A. Performance
In this section we construct a simulator and present the
scenarios we use in the remaining of the paper. Afterwards, we
compare the detector performance between the AD choosing
its action optimally and an AD that selects its attack randomly.
1) Simulator and Scenarios: Simulations are carried out in
the following way. First, we randomly generate one sequence,
Xn. Then we generate 106 sequences Y n and we calculate
� such that (7) holds. To deal with the probabilistic nature
of the delay, we repeat the following 50 times: we apply
Dn1 , next, we implement the adversary action according to
(10). Subsequently, we introduce another delay Dn2 . Finally,
we calculate the utility for this Xn using (6). We repeat
the whole process for 1000 different Xn, the plots show
the average utility for the 1000 sequences, ū. Recall that the
utility function is the probability of detection. In order to show
that AD is acting rationally we compare it with an AD that
introduces delays randomly, i.e., an is an independent and
identically distributed (i.i.d.) sequence uniformly distributed
between 0 and Amax.
Note that (3) needs an estimation of f∆D and f∆Y , to
this end we apply kernel smoothing techniques [7]. As it is
customary, we separate the data into two subsets: training, to
obtain the pdfs, and test, used in the simulator, using 50% of
the samples for each.
Scenario A represents a stepping stone that forwards SSH
traffic inside the Amazon Web Services network. TA-1, AD
and TA-2 (cf. Figure 1) are EC2 instances located in Vir-
ginia, Oregon and California, respectively. We use the IPDs
from 8746 replayed SSH connection captures with 64 million
packets from [8] and [9]. The simulated delays correspond to
Scenario 10 from [10].
Scenario B simulates a web page accessed from Tor network
whose real origin is to be found. In it, TA-1 corresponds to
the web server, AD to the Tor entry relay, and TA-2 to the
client. For instance, this case can correspond to a company
in whose forum an anonymous insulting post has been placed
using Tor and it is to be known whether the source comes
from an employee within the company. We use the IPDs
of 113690 replayed HTTP connections that sum around 139
million packets taken from the same repositories. The delays
correspond to the measurements of Scenario 11 from [10].
Results are depicted in Figures 2a and 2b for Scenario A
and B, respectively. We see that if AD chooses the delays
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0
0.1
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0.9
1
P
F
ū
Opt. AD (L=5, A
max
=0.5s)
Non Opt. AD (L=5, A
max
=0.5s)
Opt. AD (L=10, A
max
=0.1s)
Non Opt. AD (L=10, A
max
=0.1s)
Opt. AD (L=10, A
max
=0.5s)
Non Opt. AD (L=10, A
max
=0.5s)
(a) Scenario 1
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0.1
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1
P
F
u
Opt. AD (L=10, A
max
=0.5s)
Non−Opt. AD (L=10, A
max
=0.5s)
Opt. AD (L=25, A
max
=0.1s)
Non−Opt. AD (L=25, A
max
=0.1s)
Opt. AD (L=25, A
max
=0.5s)
Non−Opt. AD (L=25, A
max
=0.5s)
(b) Scenario 2
Fig. 2: Performance under a delaying AD model.
optimally, the impact of the attack is much larger than using
random delays.
V. CHAFF TRAFFIC AND FLOW SPLITTING
Hitherto, we have assumed that there exists a one-to-one
relation between the flows at the creator and detector; i.e.,
no packets are added or removed. In this section, we make
a robust test to repacketization and study the game when, in
addition to random delays, AD can also insert chaff traffic and
divide the flow, and TA-2 observes only one subflow.
To deal with packet addition and removal, TA matches each
packet from xn with the most likely from wm, m ≤ (1 +
PA)n, denoting this as i → j, as follows: |xi − (wj − ρ)| <
|xi − (wk − ρ)|, ∀k 6= j, and to avoid considering it lost
|xi − (wj − ρ)| > γ, where ρ is a synchronization constant
obtained through an exhaustive search (auto-synchronization
property), and γ is a threshold for which a packet is considered
lost. To prevent that two packets i1 and i2 are matched to the
same j packet, the set of possible matching candidates for
the later packet is reduced to the non-matched ones. Also γ
should be big enough so that the probability that a packet
is considered lost when it actually is not is very small, for
instance our simulation uses γ = Q|∆D|,0.999 + Amax where
Q|∆D|,0.999 means the 0.999-quantile of the absolute value of
∆D. This procedure outputs two subsequences, wn2 and xn2 ,
where n2 ≤ n.
After this matching we apply a modification to ΛAD in (3)
that takes into account the new sequence length as follows:
ΛAD(w
n2 , xn2 , ân2) = (n− n2) log(PL) +
n2−1∑
i=1
log (PL
+(1− PL)
f∆D(∆wi −∆xi −∆âi)
f∆Y (∆wi)
)
,
(11)
We propose a new AD model that apart from adding delays
as previously, it can remove up to PL · n packets and add at
most PA · n dummy packets. Formally, the available actions
for the adversary are:
AAD = {an × ln × cnA : 0 ≤ ai ≤ Amax, li = {0, 1}
n∑
i=1
li
n
≤ PL,
nA
n
≤ PA, m = n+ nA −
n∑
i=1
li}, (12)
where ln is a binary sequence that represents which packets
are removed from the flow, and cnA is the sequence with the
timing of the nA introduced dummy packets.
A. Results
To evaluate the proposed robust algorithm, we modify
the simulator using the matching process as follows: longer
sequences, i.e. Y n+bPAnc, are needed to calculate �. After-
wards, AD chooses its action such that (11) is minimized. We
compare the optimal AD with two non-optimal ADs: a) NO1
AD chooses its attack randomly, i.e an is an i.i.d. sequence
uniformly distributed between 0 and Amax, ln is a binary
random sequence that contains bnPLc ‘1’s, and cnA is an i.i.d.
sequence uniformly distributed between the timing of the first
packet and the timing of the last packet. The b) NO2 AD
selects an to minimize (11) (optimally) but chooses ln and
cnA identically as the previous AD.
Results are depicted in Figures 3a and 3b. We see that the
chaff traffic location when there are no losses does not make
a big impact (the Opt-AD and NO-2 AD lines difference is
very small). The rest of the data confirm that AD can harm
the TA considerably more when deciding its actions logically
than acting randomly.
VI. CONCLUSIONS
Using a game theoretic framework we have analyzed the
flow linking problem. This problem consists in deciding if
two flows are linked, having an adversary in the middle that
tries to impair the correlation. Using this framework we obtain
the optimal choices if both players act rationally. However,
in a real implementation finding these optimal choices is not
computationally feasible. This made us restrict the decoder to
those that estimate the attack. We apply it to two different
adversaries, one that only delays packets and another that can
also add and drop packets from the flow. While in the present
work the original flow is given, a future work will allow this
flow to be modified through a watermark.
ACKNOWLEDGMENT
Research supported by Iberdrola Foundation through the
Prince of Asturias Endowed Chair in Information Science and
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0
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
P
F
u
Opt. AD (P
A
=1, P
L
=0.5)
NO1 AD (P
A
=1, P
L
=0.5)
NO2 AD (P
A
=1, P
L
=0.5)
Opt. AD (P
A
=1, P
L
=0)
NO1 AD (P
A
=1, P
L
=0)
NO2 AD (P
A
=1, P
L
=0)
Opt. AD (P
A
=0, P
L
=0.5)
NO1 AD (P
A
=0, P
L
=0.5)
NO2 AD (P
A
=0, P
L
=0.5)
(a) Scenario 1, L=20, Amax = 500ms
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−5
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10
0
0
0.1
0.2
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0.4
0.5
0.6
0.7
0.8
0.9
1
P
F
u
Opt. AD (P
A
=1, P
L
=0.5)
NO1 AD (P
A
=1, P
L
=0.5)
NO2 AD (P
A
=1, P
L
=0.5)
Opt. AD (P
A
=1, P
L
=0)
NO1 AD (P
A
=1, P
L
=0)
NO2 AD (P
A
=1, P
L
=0)
Opt. AD (P
A
=0, P
L
=0.5)
NO1 AD (P
A
=0, P
L
=0.5)
NO2 AD (P
A
=0, P
L
=0.5)
(b) Scenario 2, L=30, Amax = 500ms
Fig. 3: Performance under chaff packets and removed packets.
Related Technologies.
REFERENCES
[1] S. Staniford-Chen and L. Heberlein, “Holding intruders accountable on
the internet,” in Security and Privacy, 1995. Proceedings., 1995 IEEE
Symposium on, may 1995, pp. 39 –49.
[2] X. Luo, P. Zhou, J. Zhang, R. Perdisci, W. Lee, and R. K. C. Chang,
“Exposing invisible timing-based traffic watermarks with BACKLIT,”
in Proceedings of the 27th Annual Computer Security Applications
Conference. ACM, 2011, pp. 197–206.
[3] D. L. Donoho, A. G. Flesia, U. Shankar, V. Paxson, J. Coit, and
S. Staniford, “Multiscale stepping-stone detection: detecting pairs of
jittered interactive streams by exploiting maximum tolerable delay,” in
Proceedings of the 5th international conference on Recent advances in
intrusion detection, ser. RAID’02. Berlin, Heidelberg: Springer-Verlag,
2002, pp. 17–35.
[4] A. Blum, D. Song, and S. Venkataraman, “Detection of interactive step-
ping stones: Algorithms and confidence bounds,” in Recent Advances in
Intrusion Detection, ser. Lecture Notes in Computer Science. Springer
Berlin / Heidelberg, 2004, vol. 3224, pp. 258–277.
[5] P. Moulin and J. O’Sullivan, “Information-theoretic analysis of informa-
tion hiding,” Information Theory, IEEE Transactions on, vol. 49, no. 3,
pp. 563–593, 2003.
[6] M. Barni and B. Tondi, “The source identification game: An information-
theoretic perspective,” IEEE Transactions on Information Forensics and
Security, vol. 8, no. 3, pp. 450–463, 2013.
[7] A. W. Bowman and A. Azzalini, Applied Smoothing Techniques for
Data Analysis: The Kernel Approach with S-Plus Illustrations (Oxford
Statistical Science Series). Oxford University Press, USA, Nov. 1997.
[8] D. Kotz, T. Henderson, I. Abyzov, and J. Yeo, “CRAWDAD trace
set dartmouth/campus/tcpdump (v. 2004-11-09),” http://crawdad.cs.
dartmouth.edu/dartmouth/campus/tcpdump, Nov. 2004.
[9] R. R. R. Barbosa, R. Sadre, A. Pras, and R. van de Meent, “Sim-
pleweb/university of twente traffic traces data repository,” Centre for
Telematics and Information Technology University of Twente, Enschede,
Technical Report, 2010.
[10] J. A. Elices and F. Pérez-González, “Measures to model delays on
internet,” http://www.unm.edu/∼elices/captures.html, Jan. 2013.
http://crawdad.cs.dartmouth.edu/dartmouth/campus/tcpdump
http://crawdad.cs.dartmouth.edu/dartmouth/campus/tcpdump
http://www.unm.edu/~elices/captures.html
I Introduction
II Notation and Basic Concepts
II-A Game Theory
III Traffic Analysis Game
IV Delaying Adversary model
IV-A Performance
IV-A1 Simulator and Scenarios
V Chaff traffic and flow splitting
V-A Results
VI Conclusions
References
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