IBM AIX 7.2 and 7.3 are operating systems widely used in enterprise environments. A security issue has been identified in the Network Installation Management (NIM) nimsh service related to SSL/TLS protection mechanisms. This vulnerability, indexed as CVE-2024-56347, exposes a potential remote command execution risk for affected systems.

A successful exploitation of this vulnerability allows a remote attacker to execute arbitrary commands on the targeted system by bypassing the intended SSL/TLS protection mechanism in the nimsh service. This post provides an overview of the vulnerability, information about the affected systems, and steps on how to mitigate this security risk.

Vulnerability Details

Severity: Critical
CVSS Score: 9.8 (CVSS:3./AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H)
Affected products and versions: IBM AIX 7.2 and 7.3

The vulnerability lies in improper process controls of the SSL/TLS encryption and secure communication channels within the nimsh service. In a specific scenario, the attacker crafts a malicious SSL/TLS packet and bypasses the intended security mechanisms, leading to command executions on the target machine.

The following code snippet demonstrates a partial bypass of the SSL/TLS protection mechanisms

import socket
import ssl

target = ('vulnerable-aix-server', 3901)
payload = b'COMMAND_TO_EXECUTE'

sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)

wrapped_socket = ssl.wrap_socket(sock, ssl_version=ssl.PROTOCOL_SSLv23)

wrapped_socket.connect(target)
wrapped_socket.sendall(payload)
wrapped_socket.close()

This code represents an attacker targeting an AIX server with the IP address vulnerable-aix-server via the nimsh service on port 3901, and executing a command on that server via the crafted malicious SSL/TLS packet. Note that this is only a partial implementation and further details about exploitation are withheld to prevent any misuse.

Mitigation and Recommendations

To resolve this issue and effectively mitigate the risk associated with CVE-2024-56347, IBM has released patches for affected systems and encourages users to apply these fixes immediately:

- For IBM AIX 7.2, apply the patch IV95762
- For IBM AIX 7.3, apply the patch IV95763

Additionally, adhere to the following security best practices

1. Limit the exposure of the nimsh service to the internet by using firewalls to restrict access to only trusted IP addresses.
2. Regularly monitor and review network traffic for suspicious activity pointing to exploitation attempts.
3. Schedule a proactive security patch management strategy to maintain up-to-date systems and reduce the attack surface.
4. Implement intrusion detection and prevention systems (IDS/IPS) for better network security.

Original References and Additional Information

1. IBM Security Bulletin
2. National Vulnerability Database - CVE-2024-56347

Conclusion

The disclosed vulnerability in IBM AIX 7.2 and 7.3 nimsh service poses a significant security risk due to the possibility of remote command execution by attackers. Organizations utilizing these systems must apply the released patches from IBM and follow best practices to mitigate this critical vulnerability and maintain overall system security.

Timeline

Published on: 03/18/2025 17:15:44 UTC