CVE-2012-4817 in AIX
Summary
by MITRE
The NFSv4 client implementation in IBM AIX 5.3, 6.1, and 7.1, and VIOS before 2.2.1.4-FP-25 SP-02, does not properly handle GID values, which allows remote attackers to cause a denial of service via unspecified vectors.
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 04/13/2021
The vulnerability identified as CVE-2012-4817 represents a critical flaw in the Network File System version 4 client implementation within IBM AIX operating systems and Virtual I/O Server environments. This issue affects multiple versions including AIX 5.3, 6.1, and 7.1, as well as VIOS versions prior to 2.2.1.4-FP-25 SP-02, demonstrating the widespread nature of the affected platforms. The vulnerability specifically targets the handling of Group Identifier (GID) values during NFSv4 client operations, creating a potential avenue for remote exploitation that could severely impact system availability and operational integrity.
The technical root cause of this vulnerability lies in the improper validation and processing of GID values within the NFSv4 client implementation. When the client receives NFSv4 requests containing malformed or unexpected GID values, the system fails to properly handle these inputs, leading to potential system instability. This flaw operates at the protocol level where the NFS client processes group identifiers associated with file access controls and permissions. The vulnerability manifests when the system encounters GID values that exceed expected boundaries or contain invalid formats, causing the client implementation to either crash or enter an inconsistent state that results in denial of service conditions. This type of error handling deficiency falls under the CWE-248 category of "Uncaught Exception" and represents a classic example of improper input validation that can lead to system termination.
The operational impact of CVE-2012-4817 extends beyond simple service disruption, potentially affecting critical enterprise operations that depend on NFS file sharing services. Organizations utilizing affected IBM AIX systems and VIOS environments face significant risk of unplanned downtime and data accessibility issues when remote attackers exploit this vulnerability. The denial of service condition can affect multiple concurrent users and applications that rely on NFSv4 file services, creating cascading effects throughout the enterprise infrastructure. From an attacker perspective, this vulnerability aligns with ATT&CK technique T1499.004 for "Network Denial of Service" and represents a medium to high severity threat that could be exploited by adversaries with network access to the affected systems. The vulnerability's remote exploitability means that attackers do not require local access or credentials to potentially disrupt services, making it particularly dangerous in enterprise environments where NFS services are commonly exposed to external networks.
Mitigation strategies for CVE-2012-4817 should prioritize immediate patch application from IBM, as the vendor has released specific fixes for the affected versions. Organizations should implement network segmentation to limit exposure of NFS services to trusted networks only, reducing the attack surface for potential exploitation. Monitoring and logging of NFS client activities should be enhanced to detect anomalous GID value processing patterns that might indicate attempted exploitation. System administrators should also consider implementing firewall rules that restrict NFSv4 traffic to necessary endpoints only, while maintaining regular vulnerability assessments to identify similar issues in other network services. The vulnerability highlights the importance of robust input validation and exception handling in system components, particularly those handling network protocols where external inputs must be carefully validated to prevent system instability and maintain availability.