Cisco IOS XE Software IOx Guest Shell Namespace Protection Vulnerability

Vulnerability

The vulnerability exists in the filesystem of Cisco IOS XE Software when the IOx Guest Shell is enabled. Due to insufficient file permissions, an authenticated local attacker within the guest shell can modify files that should be restricted, thereby altering namespace container protections. Affected versions include multiple Cisco IOS XE releases; users should consult the Cisco Security Advisory [1] for a complete list.

Exploitation

An attacker must have authenticated local access to the IOx Guest Shell on the affected device. No additional privileges are required beyond that access. The attacker can then modify specific files that they should not have permission to change, leveraging the weak file permissions to escape the intended container restrictions.

Impact

Successful exploitation allows the attacker to remove namespace container protections, enabling file actions outside the container's namespace. This compromises the isolation provided by the container, potentially leading to unauthorized access or modification of host filesystem resources.

Mitigation

Cisco has released software updates to address this vulnerability. Users should upgrade to fixed versions as indicated in the Cisco Security Advisory [1]. The Cisco IOS Software Checker tool can help determine exposure and the appropriate fixed release. No workarounds are available.