CVE-2019-12670

A vulnerability in the filesystem of Cisco IOS XE Software could allow an authenticated, local attacker within the IOx Guest Shell to modify the namespace container protections on an affected device. The vulnerability is due to insufficient file permissions. An attacker could exploit this vulnerability by modifying files that they should not have access to. A successful exploit could allow the attacker to remove container protections and perform file actions outside the namespace of the container.

Weakness

During installation, installed file permissions are set to allow anyone to modify those files.

Affected Software

Potential Mitigations

• Compartmentalize the system to have “safe” areas where trust boundaries can be unambiguously drawn. Do not allow sensitive data to go outside of the trust boundary and always be careful when interfacing with a compartment outside of the safe area.
• Ensure that appropriate compartmentalization is built into the system design, and the compartmentalization allows for and reinforces privilege separation functionality. Architects and designers should rely on the principle of least privilege to decide the appropriate time to use privileges and the time to drop privileges.

Related Attack Patterns

• https://cwe.mitre.org/data/definitions/1.html
• https://cwe.mitre.org/data/definitions/127.html
• https://cwe.mitre.org/data/definitions/81.html

References

• https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20190925-iox-gs