applications), or allowed to inject code into other applications and have access to the net, by having the system assign access levels for users or programs according to a set of determined rules. It also can control file/registry security (what programs can read and write to the file system/registry). In such an environment, viruses and Trojans have fewer opportunities for infecting a computer. The SELinux and Apparmor security frameworks are two such implementations for Linux. Security researchers rely heavily on sandboxing technologies to analyse malware behavior. By creating an environment that mimics or replicates the targeted desktops, researchers can evaluate how malware infects and compromises a target host. Numerous malware analysis services are based on the sandboxing technology. Google Native Client is a sandbox for running compiled C and C++ code in the browser efficiently and securely, independent of the user's operating system. Capability systems can be thought of as a fine-grained sandboxing mechanism, in which programs are given opaque tokens when spawned and have the ability to do specific things based on what tokens they hold. Capability-based implementations can work at various levels, from kernel to user-space. An example of capability-based user-level sandboxing involves HTML rendering in a Web browser. Secure Computing Mode (seccomp) strict mode, seccomp only allows the write(), read(), exit(), and sigreturn() system calls. HTML5 has a "sandbox" attribute for use with iframes. Java virtual machines include a sandbox to restrict the actions of untrusted code, such as a Java applet. The .NET Common Language Runtime provides Code Access Security to enforce restrictions on untrusted code. Software Fault Isolation (SFI), allows running untrusted native code by sandboxing all store, read and jump assembly instructions to isolated segments of memory. Some of the use cases for sandboxes include the following: Online judge systems to test programs in programming contests. New-generation pastebins allowing users to execute pasted code snippets on the pastebin's server. See also Sandboxie seccomp Shade sandbox Test bench Tor (anonymity network) References External links Security In-Depth for Linux Software: Preventing and Mitigating Security Bugs Sandbox The Chromium Projects FreeBSD capsicum(4) man page a lightweight OS capability and sandbox framework OpenBSD pledge(2) man page a way to restrict system operations Sandbox testing importance{sandbox} Importance of sandbox in zero day flaw Operating system security Virtualization