CVE-2021-1612

A vulnerability in the Cisco IOS XE SD-WAN Software CLI could allow an authenticated, local attacker to overwrite arbitrary files on the local system. This vulnerability is due to improper access controls on files within the local file system. An attacker could exploit this vulnerability by placing a symbolic link in a specific location on the local file system. A successful exploit could allow the attacker to overwrite arbitrary files on an affected device.

Weakness

The product, when opening a file or directory, does not sufficiently account for when the file is a symbolic link that resolves to a target outside of the intended control sphere. This could allow an attacker to cause the product to operate on unauthorized files.

Affected Software

Potential Mitigations

• Follow the principle of least privilege when assigning access rights to entities in a software system.
• Denying access to a file can prevent an attacker from replacing that file with a link to a sensitive file. Ensure good compartmentalization in the system to provide protected areas that can be trusted.

Related Attack Patterns

• https://cwe.mitre.org/data/definitions/27.html

References

• https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-sd-wan-GjR5pGOm
• https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-sd-wan-GjR5pGOm