CVE-2006-4337 in gzip
Summary
by MITRE
Buffer overflow in the make_table function in the LHZ component in gzip 1.3.5 allows context-dependent attackers to execute arbitrary code via a crafted decoding table in a GZIP archive.
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Analysis
by VulDB Data Team • 07/08/2019
The vulnerability identified as CVE-2006-4337 represents a critical buffer overflow flaw within the LHZ component of gzip version 1.3.5 that specifically affects the make_table function. This vulnerability falls under the CWE-121 category of Buffer Overflow, which occurs when a program attempts to write data beyond the boundaries of a fixed-length buffer. The issue is particularly concerning because it exists within a widely-used compression utility that processes GZIP archives, making it a potential vector for arbitrary code execution attacks.
The technical implementation of this vulnerability stems from insufficient bounds checking within the make_table function of the LHZ decompression component. When gzip processes a GZIP archive containing a malformed decoding table, the function fails to properly validate the size of incoming data before copying it into a fixed-size buffer. This allows an attacker to craft a malicious GZIP archive with oversized decoding table data that overflows the allocated buffer space, potentially corrupting adjacent memory regions and enabling code execution. The context-dependent nature of this vulnerability means that exploitation requires specific conditions related to how the archive is processed, though the attack vector remains accessible through normal file decompression operations.
The operational impact of CVE-2006-4337 extends beyond simple denial of service scenarios, as it provides attackers with the capability to execute arbitrary code with the privileges of the user running the gzip utility. This vulnerability affects systems where gzip is used for decompressing files, particularly in environments where users might encounter untrusted archives or where automated decompression processes handle files from external sources. The attack surface is broad since gzip is a standard Unix utility present on virtually all Linux and Unix systems, making the exploitation potential widespread across different platforms and deployment scenarios.
From a cybersecurity perspective, this vulnerability aligns with ATT&CK technique T1059.007 for Command and Scripting Interpreter, as successful exploitation would allow attackers to execute arbitrary commands through the compromised gzip process. The vulnerability also relates to T1203 for Exploitation for Client Execution when the malicious archive is processed by applications that invoke gzip for decompression. Mitigation strategies should include immediate patching of gzip to versions that address this buffer overflow, implementing proper input validation for all decompression operations, and employing sandboxing techniques to limit the privileges of decompression processes. Additionally, organizations should consider implementing network-based detection measures to identify and block suspicious GZIP archives that might contain crafted malicious decoding tables.
The root cause of this vulnerability demonstrates poor defensive programming practices that violate fundamental security principles. Modern secure coding standards emphasize the importance of input validation, bounds checking, and proper memory management to prevent such buffer overflow conditions. The vulnerability serves as a reminder of the critical importance of thorough code review and testing, particularly for components that handle untrusted input data. Security practitioners should ensure that all decompression libraries and utilities undergo regular security assessments to identify and remediate similar buffer overflow vulnerabilities that could provide attackers with unauthorized code execution capabilities.