CVE-2009-2434 in AIX
Summary
by MITRE
Buffer overflow in the syscall implementation in IBM AIX 5.3 allows local users to gain privileges via unspecified vectors.
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Analysis
by VulDB Data Team • 08/12/2021
The vulnerability identified as CVE-2009-2434 represents a critical buffer overflow condition within the system call implementation of IBM AIX 5.3 operating system. This flaw exists at the kernel level where the system call handling mechanism fails to properly validate input parameters, creating an exploitable condition that can be leveraged by local attackers to escalate their privileges. The vulnerability is particularly concerning because it operates within the core system call interface that all applications and processes utilize when requesting kernel services, making it a prime target for privilege escalation attacks.
The technical implementation of this buffer overflow stems from inadequate bounds checking within the kernel's system call processing code. When a process makes a system call to the affected AIX version, the kernel routine responsible for handling the call does not sufficiently validate the size or content of input buffers, allowing an attacker to overwrite adjacent memory locations. This memory corruption can potentially overwrite critical kernel data structures, return addresses, or privilege control mechanisms. The vulnerability manifests through unspecified vectors, indicating that multiple attack paths exist within the system call interface that could trigger the buffer overflow condition. According to CWE-121, this vulnerability maps directly to a buffer overflow condition where insufficient bounds checking allows memory to be overwritten beyond allocated buffer boundaries.
From an operational perspective, this vulnerability presents a severe risk to systems running IBM AIX 5.3 as local users who can execute code on the system can potentially exploit this flaw to gain root or administrative privileges. The attack requires local access but does not necessitate network connectivity, making it particularly dangerous in environments where local access is not strictly controlled. Once successfully exploited, attackers can execute arbitrary code with the highest privilege level, potentially leading to complete system compromise, data exfiltration, or persistent access. The attack vector typically involves crafting malicious system calls that trigger the overflow condition, which can be accomplished through specially crafted programs or by leveraging existing system utilities that make system calls.
The impact extends beyond immediate privilege escalation to encompass broader system security implications. Organizations running IBM AIX 5.3 are particularly vulnerable since this version is no longer supported by IBM, leaving systems without security patches or updates to address such fundamental kernel-level vulnerabilities. The ATT&CK framework categorizes this vulnerability under privilege escalation techniques, specifically targeting the system call interface as a means to bypass security controls. Security professionals should note that the lack of specific vector details in the original CVE description suggests that multiple system call interfaces may be affected, potentially including file operations, process management, or network-related system calls that interact with kernel memory structures.
Mitigation strategies for CVE-2009-2434 require immediate action from system administrators, including applying the appropriate security patches from IBM if available, or implementing restrictive access controls to limit local user privileges. System hardening measures should focus on reducing the attack surface by disabling unnecessary system calls and implementing proper privilege separation. The recommended approach includes deploying kernel security modules, enabling system call filtering, and establishing robust monitoring for suspicious system call patterns that might indicate exploitation attempts. Organizations should also consider implementing the principle of least privilege, ensuring that local users have minimal necessary permissions to reduce the potential impact of successful exploitation. Additionally, regular security audits and vulnerability assessments should be conducted to identify other potential buffer overflow conditions within the system call interface or other kernel components that may present similar security risks.