CVE-2010-1039 in VIOS
Summary
by MITRE
Format string vulnerability in the _msgout function in rpc.pcnfsd in IBM AIX 6.1, 5.3, and earlier; IBM VIOS 2.1, 1.5, and earlier; NFS/ONCplus B.11.31_09 and earlier on HP HP-UX B.11.11, B.11.23, and B.11.31; and SGI IRIX 6.5 allows remote attackers to execute arbitrary code via an RPC request containing format string specifiers in an invalid directory name.
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Analysis
by VulDB Data Team • 01/27/2025
This vulnerability represents a critical format string flaw in the rpc.pcnfsd daemon across multiple enterprise operating systems including IBM AIX, IBM VIOS, HP-UX, and SGI IRIX. The issue resides within the _msgout function which processes RPC requests containing malformed directory names with format string specifiers. When the system encounters an invalid directory name during NFS operations, it passes this untrusted input directly to a printf-style function without proper sanitization, creating a classic format string vulnerability that can be exploited by remote attackers. The vulnerability affects widely deployed enterprise systems where NFS services are critical for file sharing and storage operations, making it particularly dangerous in production environments.
The technical exploitation of this vulnerability occurs when an attacker sends a specially crafted RPC request containing format string specifiers such as %x, %s, or %n in the directory name parameter. The _msgout function processes this input directly through a vulnerable printf call, allowing attackers to read arbitrary memory locations, overwrite function pointers, or inject malicious code into the process memory space. This type of vulnerability is classified as CWE-134 under the Common Weakness Enumeration framework, specifically addressing the improper use of format strings. The attack vector is particularly concerning because it requires no authentication and can be executed over the network through standard RPC mechanisms, making it accessible to any remote attacker with network connectivity to the affected systems.
The operational impact of this vulnerability extends beyond simple code execution, as it can lead to complete system compromise and unauthorized access to sensitive data stored on the affected servers. Attackers can leverage the format string vulnerability to escalate privileges, gain persistent access, or disrupt critical file services that many enterprise applications depend upon. The vulnerability affects multiple vendor platforms simultaneously, indicating a widespread issue in the industry's adoption of legacy NFS implementations. According to ATT&CK framework categorization, this vulnerability maps to T1059.007 for command and script injection, and T1068 for exploit for privilege escalation, making it a significant threat to enterprise security postures. The presence of this vulnerability in widely used operating systems like AIX and HP-UX creates a substantial risk for organizations relying on these platforms for critical infrastructure operations.
Mitigation strategies should focus on immediate patching of affected systems through vendor-provided security updates, which typically address the vulnerability by properly sanitizing input before passing it to printf functions. Organizations should also implement network segmentation to limit access to NFS services, disable unnecessary RPC services, and monitor for suspicious RPC traffic patterns. Additional defensive measures include implementing intrusion detection systems to detect format string exploitation attempts, applying network access controls to restrict RPC communication, and conducting regular security assessments to identify other potential format string vulnerabilities in legacy applications. The vulnerability demonstrates the ongoing risks associated with maintaining older operating system versions and underscores the importance of maintaining up-to-date security patches across enterprise infrastructure to prevent exploitation of known vulnerabilities.