title: Why do I have access to this file?
body: <p>I have this file:</p>
  
  <pre><code>-rw-rw----+  1 git    git    16959 Jul 25 07:37 github.conf
  </code></pre>
  
  <p>I am this guy: </p>
  
  <pre><code>$ whoami
  admin
  $ id
  uid=501(admin) gid=501(admin) groups=501(admin),4(adm)
  </code></pre>
  
  <p>I can also say this: </p>
  
  <pre><code>$ cat /etc/passwd | grep admin
  gnats:x:41:41:Gnats Bug-Reporting System (admin):/var/lib/gnats:/usr/sbin/nologin
  admin:x:501:501:,,,:/home/admin:/bin/bash
  
  $ cat /etc/group | grep -E 'admin|git'
  adm:x:4:admin
  git:x:500:
  admin:x:501:admin
  </code></pre>
  
  <p>How is it possible I can read this file <code>github.conf</code>. I don't belong to the <code>git</code> group and I am not <code>git</code>. How is it then possible?</p>