A recent vulnerability, CVE-2022-22351, has been reported in the IBM AIX 7.1, 7.2, 7.3, and VIOS 3.1 operating systems. This security flaw could allow a non-privileged trusted host user to exploit the Network Installation Manager (NIM) shell daemon, known as "nimsh," causing a denial of service (DoS) attack. The IBM X-Force ID for this vulnerability is 220396.

This blog post will provide more details on the nature of the exploit and potential repercussions. We'll also offer code snippets to help AIX administrators check their systems for the vulnerability and understand how to mitigate the potential risks.

Exploit Details

IBM AIX operating systems utilize the NIM framework to manage resources and perform software installations on remote systems. The NIM shell daemon, or "nimsh," facilitates communication between the NIM master and clients.

It has been discovered that the nimsh daemon contains a vulnerability that could be exploited by a non-privileged trusted host user to cause the nimsh daemon on another trusted host to stop responding, effectively creating a denial of service situation. This can lead to network instability and a loss of critical services for the impacted systems, as well as potentially providing an attacker with an opportunity for further exploitation.

According to IBM's security bulletin (link provided below), the vulnerability has been assigned a CVSS Base Score of 3.7, categorizing it as a "low" impact vulnerability.

Checking for Vulnerability

AIX systems administrators can check for the existence of the nimsh daemon on their systems by running the following command:

$ lssrc -s nimsh

If the nimsh daemon is not installed or running, the system is not affected by this vulnerability.

Mitigation and Recommendations

IBM has released patches for AIX 7.1, 7.2, 7.3, and VIOS 3.1 that fix the vulnerability. Administrators should apply these fixes as soon as possible to protect their systems from potential denial of service attacks.

IBM AIX Security Bulletin - CVE-2022-22351

In addition to applying the patches, administrators should follow industry best practices for securing their AIX systems, including:

Conclusion

Although the CVE-2022-22351 vulnerability has been categorized as low impact, AIX administrators should take the necessary steps to secure their systems against potential attacks. By staying informed about vulnerabilities, updating systems promptly, and practicing good security hygiene, administrators can maintain a strong security posture for their organizations.

References

1. CVE-2022-22351
2. IBM AIX Security Bulletin - CVE-2022-22351
3. IBM X-Force ID: 220396
4. IBM AIX Network Installation Manager (NIM)

Timeline

Published on: 03/07/2022 17:15:00 UTC
Last modified on: 03/18/2022 13:40:00 UTC