Overview
A critical security vulnerability, identified as CVE-2025-36236, has been discovered in IBM AIX 7.2, 7.3 and IBM VIOS 3.1, and 4.1 Network Installation Management (NIM) server, formerly known as the NIM master. This vulnerability allows a remote attacker to perform directory traversal, potentially leading to arbitrary file writes on the affected system. The affected service is the `nimesis` daemon. Immediate action is recommended to mitigate this risk.
Technical Details
The vulnerability stems from insufficient input validation within the `nimesis` service. An attacker can exploit this by crafting a malicious URL request containing directory traversal sequences (e.g., `../`) within the file path parameter. This allows them to bypass intended security restrictions and write files to locations outside the designated NIM server directories. This could be used to overwrite system files, inject malicious code, or compromise the integrity and availability of the system.
CVSS Analysis
- CVE ID: CVE-2025-36236
- Severity: HIGH
- CVSS Score: 8.2
A CVSS score of 8.2 indicates a high severity vulnerability. This score reflects the potential for significant impact on confidentiality, integrity, and availability, combined with a relatively low attack complexity. This vulnerability can be exploited remotely without requiring any user interaction or special privileges.
Possible Impact
Successful exploitation of CVE-2025-36236 can have severe consequences, including:
- Arbitrary File Write: Attackers can write arbitrary files to the system, potentially overwriting critical system files.
- Code Execution: By writing malicious code to specific locations, attackers can achieve remote code execution.
- System Compromise: Successful exploitation can lead to a complete compromise of the affected NIM server, giving attackers full control over the system.
- Data Breach: Access to sensitive data stored on the NIM server or accessible through it may be compromised.
Mitigation or Patch Steps
IBM has released patches to address this vulnerability. It is highly recommended that all affected systems be updated immediately. Follow these steps:
- Identify Affected Systems: Determine which IBM AIX 7.2, 7.3 and IBM VIOS 3.1, and 4.1 NIM servers are present in your environment.
- Apply the Fix: Download and install the appropriate fix package from IBM Fix Central. The fix information can be found at the following link: IBM Support Page for CVE-2025-36236
- Verify Installation: After applying the fix, verify that the `nimesis` service is running the patched version.
- Monitor for Suspicious Activity: Continuously monitor affected systems for any signs of compromise, such as unusual file modifications or unauthorized access attempts.
