CVE-2010-2322 in FastJar
Summary
by MITRE
Absolute path traversal vulnerability in the extract_jar function in jartool.c in FastJar 0.98 allows remote attackers to create or overwrite arbitrary files via a full pathname for a file within a .jar archive, a related issue to CVE-2010-0831. NOTE: this vulnerability exists because of an incomplete fix for CVE-2006-3619.
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Analysis
by VulDB Data Team • 09/18/2021
The CVE-2010-2322 vulnerability represents a critical absolute path traversal flaw within the FastJar 0.98 archive extraction utility, specifically within the extract_jar function located in jartool.c. This vulnerability arises from insufficient validation of file paths contained within .jar archive files, allowing remote attackers to manipulate the extraction process and potentially overwrite or create arbitrary files on the target system. The flaw is particularly concerning because it enables attackers to bypass normal file system access controls and execute malicious file operations with the privileges of the FastJar process. The vulnerability specifically affects the handling of full pathnames within jar archives, where absolute paths are not properly sanitized before being used in file system operations.
The technical implementation of this vulnerability stems from the incomplete fix applied to address the earlier CVE-2006-3619 vulnerability, creating a regression that allows attackers to exploit path traversal mechanisms in the jar extraction process. When FastJar processes a .jar archive containing files with absolute paths, the software fails to validate whether these paths are legitimate or if they attempt to traverse outside the intended extraction directory. This weakness directly maps to CWE-22, which describes improper limitation of a pathname to a restricted directory, commonly known as path traversal or directory traversal attacks. The vulnerability operates by manipulating the pathname structure within jar files to include absolute path components such as "/tmp/" or "/etc/" that would normally be rejected but are processed due to inadequate input validation.
From an operational perspective, this vulnerability presents significant risks to systems that utilize FastJar for processing untrusted jar archives, particularly in web applications, automated build systems, or any environment where jar files are extracted from external sources. Attackers can leverage this vulnerability to overwrite critical system files, inject malicious code into existing programs, or create backdoor files that persist beyond the initial attack window. The impact extends beyond simple file manipulation to potentially enable privilege escalation attacks, as the attacker can target system configuration files, binaries, or other sensitive resources within the file system. The vulnerability is particularly dangerous in environments where FastJar is used in automated processing pipelines, as it could allow attackers to compromise entire build or deployment systems.
Security mitigations for CVE-2010-2322 should focus on implementing comprehensive input validation and path sanitization within the jar extraction process. Organizations should immediately upgrade to patched versions of FastJar that properly handle absolute pathnames and implement proper directory traversal prevention mechanisms. The recommended approach includes validating all extracted file paths against a whitelist of acceptable directories, normalizing pathnames to prevent directory traversal sequences, and ensuring that all extraction operations occur within controlled, restricted directories. Additionally, system administrators should consider implementing network segmentation and access controls to limit the impact of potential exploitation. This vulnerability aligns with ATT&CK technique T1059.007 for execution through archive extraction, and T1078 for legitimate credentials use in privilege escalation scenarios. Organizations should also implement monitoring and logging of jar extraction activities to detect anomalous file creation patterns that may indicate exploitation attempts. The vulnerability demonstrates the importance of thorough regression testing when implementing security fixes and highlights the need for comprehensive input validation across all file processing functions.