https://nalar.dev/tags/privilege-boundaries/ Recent content in Privilege Boundaries on Nalar Hugo en-us Thu, 17 Sep 2026 00:00:00 +0000 https://nalar.dev/no-new-privs-makes-exec-time-privilege-gain-irreversible/ Thu, 17 Sep 2026 00:00:00 +0000 https://nalar.dev/no-new-privs-makes-exec-time-privilege-gain-irreversible/ <h1 id="no_new_privs-makes-exec-time-privilege-gain-irreversible">no_new_privs Makes Exec-Time Privilege Gain Irreversible</h1> <p>A Linux service may deliberately execute programs that carry set-user-ID bits or file capabilities while intending to remain at its existing privilege level. Without an explicit execution boundary, <code>execve()</code> can be a privilege transition: metadata on the executable may change effective credentials or contribute capabilities to the new program.</p> <p>The <code>no_new_privs</code> task attribute changes that transition. Once set, a successful <code>execve()</code> cannot grant the task privilege that it could not exercise before the call. The attribute is inherited by descendants, survives execution, and cannot be cleared. Those properties make it a one-way constraint on a process lineage rather than a temporary option around one executable.</p>