https://sankethbk.github.io/blog/tags/setuid/Recent content in Setuid on Sanketh's BlogHugo -- 0.165.0en-usSun, 02 Aug 2026 00:00:00 +0000https://sankethbk.github.io/blog/posts/reverse-engineering/2026-08-02-setuid-binaries/Sun, 02 Aug 2026 00:00:00 +0000https://sankethbk.github.io/blog/posts/reverse-engineering/2026-08-02-setuid-binaries/<h1 id="setuid-binaries">Setuid Binaries</h1> <div class="highlight"><pre tabindex="0" style="color:#f8f8f2;background-color:#272822;-moz-tab-size:4;-o-tab-size:4;tab-size:4;-webkit-text-size-adjust:none;"><code class="language-sh" data-lang="sh"><span style="display:flex;"><span><span style="color:#75715e"># ls -la /bin/su</span> </span></span><span style="display:flex;"><span>-rwsr-xr-x <span style="color:#ae81ff">1</span> root root <span style="color:#ae81ff">67816</span> Aug <span style="color:#ae81ff">1</span> 20:00 /bin/su </span></span></code></pre></div><h3 id="types-of-permissions-and-actions">Types of permissions and actions</h3> <h2 id="1-the-three-types-of-users-who">1. The Three Types of Users (Who)</h2> <p>Linux divides the entire universe of users into three distinct categories. Permissions are always listed in this exact order:</p> <ul> <li>Owner (User): The specific person who owns the file (usually the creator).</li> <li>Group: A defined collection of users who share access (e.g., a &ldquo;developers&rdquo; or &ldquo;finance&rdquo; group).</li> <li>Others: Everyone else on the system who is not the owner and not in the group.</li> </ul> <p>The owner and group are stored in inode.</p>