CVE-2007-4004 in AIX
Summary
by MITRE
Buffer overflow in the ftp client in IBM AIX 5.3 SP6 and 5.2.0 allows local users to execute arbitrary code via unspecified vectors that trigger the overflow in a gets function call. NOTE: the client is setuid root on AIX, so this issue crosses privilege boundaries.
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Analysis
by VulDB Data Team • 06/05/2024
The vulnerability identified as CVE-2007-4004 represents a critical buffer overflow flaw within the ftp client component of IBM AIX operating systems, specifically affecting versions 5.3 SP6 and 5.2.0. This security weakness resides in the client-side ftp application that is designed with setuid root privileges, creating a severe escalation path for local attackers who can leverage this vulnerability to execute arbitrary code with elevated system privileges. The flaw manifests through unspecified vectors that ultimately trigger a buffer overflow condition during a gets function call, a well-documented pattern that has historically led to privilege escalation exploits. The gets function is particularly dangerous because it does not perform bounds checking on input data, making it susceptible to buffer overflows when user-supplied data exceeds the allocated buffer size. This particular vulnerability operates within the context of a setuid root application, meaning that any successful exploitation would immediately grant the attacker root-level access to the compromised system.
The technical implementation of this vulnerability demonstrates a classic buffer overflow scenario that aligns with CWE-121, which describes stack-based buffer overflow conditions where insufficient bounds checking allows attackers to overwrite adjacent memory locations. The operational impact of this flaw extends beyond simple code execution as it fundamentally compromises the integrity of the system's privilege model. When a local user can execute arbitrary code with root privileges, they gain complete control over the system, enabling them to modify system files, create new user accounts, install malware, or establish persistent backdoors. The attack vector through the ftp client application means that an attacker could potentially exploit this vulnerability even if they only have basic user-level access to the system, as the setuid nature of the application automatically elevates their privileges upon execution. This characteristic places the vulnerability in the ATT&CK framework category of privilege escalation, specifically under techniques that leverage setuid/setgid binaries to gain elevated system access.
The exploitation of this vulnerability requires local system access and leverages the inherent design flaw in the gets function call within the ftp client application. The buffer overflow occurs when user input exceeds the allocated buffer space, causing adjacent memory to be overwritten with attacker-controlled data. This memory corruption can be manipulated to redirect program execution flow, potentially allowing an attacker to inject and execute malicious code with root privileges. The impact of such an exploit extends to the complete compromise of the system's security model, as the attacker gains unrestricted access to all system resources, files, and processes. Organizations running affected IBM AIX versions should implement immediate mitigations including patching the vulnerable ftp client application, disabling unnecessary ftp client functionality, or implementing additional access controls to limit local user privileges. The vulnerability also underscores the importance of avoiding dangerous functions like gets in application development and demonstrates how setuid applications can serve as prime targets for privilege escalation attacks. System administrators should conduct thorough vulnerability assessments to identify all setuid applications and ensure they are properly patched and monitored for similar security flaws that could compromise system integrity.