CVE-2004-1027 in unarj
Summary
by MITRE
Directory traversal vulnerability in the -x (extract) command line option in unarj allows remote attackers to overwrite arbitrary files via an arj archive with filenames that contain .. (dot dot) sequences.
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Analysis
by VulDB Data Team • 06/05/2019
The vulnerability identified as CVE-2004-1027 represents a critical directory traversal flaw within the unarj utility's command line extraction functionality. This security weakness specifically manifests when processing arj archive files through the -x option, which is designed for extracting compressed files from archive containers. The flaw enables malicious actors to manipulate file paths during extraction processes, potentially leading to unauthorized file overwrites on the target system.
This directory traversal vulnerability stems from inadequate input validation within the unarj application's handling of archive filenames. When processing archive entries containing .. (dot dot) sequences in their pathnames, the utility fails to properly sanitize or restrict these path components, allowing attackers to navigate outside the intended extraction directory. The vulnerability is classified under CWE-22 as a "Path Traversal" attack vector, where attackers exploit insufficient restrictions on file paths to access or modify files outside the intended scope of operation. The flaw essentially permits attackers to craft malicious arj archives that contain filenames with directory traversal sequences, enabling them to overwrite files in arbitrary locations on the system.
The operational impact of this vulnerability extends beyond simple file overwrites, as it can be leveraged for more sophisticated attack vectors within the broader ATT&CK framework. Attackers can use this weakness to overwrite critical system files, configuration files, or even executables, potentially leading to privilege escalation or complete system compromise. The vulnerability is particularly dangerous because it operates at the file system level, allowing attackers to bypass normal access controls and permissions that would typically protect sensitive files. When combined with other exploitation techniques, this directory traversal vulnerability can enable attackers to establish persistent access or cause denial of service conditions by overwriting essential system components.
Mitigation strategies for CVE-2004-1027 should focus on implementing proper input validation and path sanitization within the unarj utility. System administrators should ensure that all archive extraction utilities properly validate and sanitize filenames before processing them, particularly when handling .. sequences that could indicate directory traversal attempts. The recommended approach includes implementing strict path validation that rejects any filenames containing directory traversal components, enforcing extraction to predetermined safe directories, and applying principle of least privilege when running archive extraction utilities. Organizations should also consider updating to patched versions of unarj or migrating to more secure archive handling tools that properly implement input validation. Additionally, network segmentation and access control measures can help limit the potential impact of such vulnerabilities by restricting access to systems that process untrusted archive files. The vulnerability highlights the importance of secure coding practices and input validation as fundamental security controls that prevent attackers from manipulating file system operations through maliciously crafted input data.