CVE-2005-4667 in UnZip
Summary
by MITRE
Buffer overflow in UnZip 5.50 and earlier allows user-assisted attackers to execute arbitrary code via a long filename command line argument. NOTE: since the overflow occurs in a non-setuid program, there are not many scenarios under which it poses a vulnerability, unless unzip is passed long arguments when it is invoked from other programs.
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Analysis
by VulDB Data Team • 01/04/2025
The vulnerability described in CVE-2005-4667 represents a classic buffer overflow condition affecting UnZip version 5.50 and earlier implementations. This flaw exists within the command line argument processing mechanism of the unzip utility, specifically when handling filename arguments that exceed predetermined buffer limits. The vulnerability manifests when a user provides an excessively long command line argument containing a filename, causing the software to write beyond allocated memory boundaries. Such buffer overflows typically occur when input validation is insufficient and the program fails to properly check the length of user-provided data before copying it into fixed-size memory buffers.
From a technical perspective, this vulnerability operates under CWE-121, which categorizes buffer overflow conditions where insufficient bounds checking allows attackers to overwrite adjacent memory locations. The flaw specifically impacts the command line argument parsing functionality of UnZip, making it susceptible to exploitation when the utility processes malformed input. The vulnerability requires a user-assisted attack vector, meaning an attacker must convince a victim to execute a specially crafted command line that includes an overly long filename argument. This requirement significantly limits the attack surface compared to fully autonomous exploits, as it necessitates social engineering or privilege escalation within the target environment.
The operational impact of this vulnerability extends beyond simple code execution, as it represents a potential pathway for privilege escalation and system compromise within specific contexts. While UnZip typically runs without setuid permissions, the vulnerability becomes more concerning when the utility is invoked by other programs that may have elevated privileges. This scenario creates opportunities for attackers to leverage the buffer overflow in environments where unzip is used in automated processes or system administration tasks. The attack vector becomes particularly dangerous when unzip is executed with elevated privileges through mechanisms like sudo or system scripts, as successful exploitation could allow arbitrary code execution with those elevated privileges. Additionally, the vulnerability demonstrates the importance of input validation in security-critical applications, as even non-privileged utilities can become attack vectors when used in vulnerable contexts.
Mitigation strategies for CVE-2005-4667 should focus on both immediate patching and defensive programming practices. The most effective solution involves upgrading to UnZip version 5.51 or later, where the buffer overflow has been corrected through proper bounds checking and input validation. Organizations should implement comprehensive patch management procedures to ensure all systems running UnZip are updated promptly. Beyond patching, defensive measures include implementing input length restrictions, using secure coding practices such as those recommended in the ATT&CK framework for preventing buffer overflow exploits, and monitoring system logs for unusual unzip command executions. Security teams should also consider implementing application whitelisting policies that restrict which programs can execute unzip with elevated privileges, and conduct regular security assessments to identify potential privilege escalation paths that could leverage this vulnerability. The vulnerability serves as a reminder of the critical importance of proper memory management and input validation in preventing exploitation of buffer overflow conditions.