CVE-2025-32463: Exploiting Sudo's chroot to Gain Root Privileges

Sudo is a critical utility in Unix-like systems that allows delegated privilege escalation — typically enabling a user to run specific commands as root without sharing the root password. However, even powerful tools like Sudo are not immune to security flaws. One such vulnerability, CVE-2025-32463, exposes a significant risk in environments where Sudo version 1.9.14 through 1.9.17 is deployed.

This vulnerability arises from the relatively new --chroot (-R) option introduced in the 1.9 series, allowing users to run commands inside a different root filesystem. Misuse or lack of awareness about how this interacts with system components like nsswitch.conf opens the door to local privilege escalation — no special sudoers configuration required.

In this article, we’ll walk through the concept, the testing environment, and how the exploit works in practice.

Understanding the Vulnerability

What Is CVE-2025-32463?

CVE-2025-32463 is a local privilege escalation vulnerability in Sudo versions 1.9.14 through 1.9.17, affecting the way it handles the --chroot option (-R). This feature allows a user to execute commands in a different root directory.

The issue occurs because:

• Sudo uses the Name Service Switch (NSS) via /etc/nsswitch.conf to resolve user, group information and so on.

• When running in a chrooted environment with sudo -R, it still loads libraries and config files (like nsswitch.conf) from the chroot directory.

• A malicious user can craft a fake root filesystem with manipulated nsswitch.conf and malicious .so libraries to hijack NSS lookups.

Once these malicious libraries are loaded in the chroot, they execute with root privileges, giving the attacker a root shell.

Environment and Setup

• Tested Distribution: Kali Linux

• Sudo Version: 1.9.16p2 (Vulnerable)

• User Access: Local unprivileged user

• No special sudoers rule defined — only default configuration required.

How a normal user can escalate privilege to root user

1.     Tested this proof-of-concept on Kali Linux with the following version of Sudo: 1.9.16p2

Here the version of sudo is 1.9.16p2

2.     Understanding nsswitch.conf in the Concept of Sudo Exploitation

/etc/nsswitch.conf controls how Linux looks up users, groups, hosts, etc. It tells the system where to search — like files, systemd, or dns, If an attacker changes it (in chroot), sudo may load fake .so libs, and That opens a path to root by default if sudo -R is used.

3.    Exploit Using Public CVE-2025-32463 Script

Normal user can’t see shadow file but her we are going to escalate privilege as root user.

4.     Finally exploited CVE-2025-32463

Now here we can see a normal user has escalated his privilege as a root user.

A root user can see shadow file and has higher privileges.

Now, We have successfully exploited CVE-2025-32463.

Impact

• Local Privilege Escalation to Root

• No sudoers misconfiguration required

• Exploitable by any local user on a default system

• Particularly dangerous on multi-user systems or development environments like Kali, where multiple users may have shell access.

Mitigation and Fixes

• Upgrade Sudo to version 1.9.18 or newer, where the issue has been patched.

• Restrict usage of sudo -R through sudoers policy if possible.

• Use namespaces or containers instead of sudo -R for chrooting behavior.

Conclusion

CVE-2025-32463 is a prime example of how modern features, even in well-established tools like Sudo, can introduce subtle yet serious security flaws. The use of --chroot without proper safeguards opened the door for local users to hijack execution flow through fake NSS modules — ultimately leading to full root access.

Security practitioners and system administrators should immediately patch affected systems and audit usage of sudo -R, especially in environments with multiple local users.