CVE-2007-4559 in Python
Summary
by MITRE
Directory traversal vulnerability in the (1) extract and (2) extractall functions in the tarfile module in Python allows user-assisted remote attackers to overwrite arbitrary files via a .. (dot dot) sequence in filenames in a TAR archive, a related issue to CVE-2001-1267.
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Analysis
by VulDB Data Team • 10/16/2025
The directory traversal vulnerability identified as CVE-2007-4559 affects the tarfile module in Python, specifically impacting the extract and extractall functions. This flaw represents a critical security weakness that enables remote attackers to manipulate file extraction processes and potentially overwrite arbitrary files on the target system. The vulnerability stems from insufficient input validation within the tarfile processing logic, allowing maliciously crafted archive files to contain filenames with .. (dot dot) sequences that traverse directory structures beyond the intended extraction location.
The technical implementation of this vulnerability involves the tarfile module's failure to properly sanitize or validate filenames during archive extraction operations. When processing tar archives containing filenames with directory traversal sequences, the module does not adequately check whether these paths remain within the designated extraction directory boundaries. This allows attackers to specify paths that resolve to locations outside the intended target directory, enabling them to overwrite system files, configuration files, or other sensitive data. The vulnerability is particularly dangerous because it operates at the file system level, bypassing many application-level security controls that might otherwise prevent such operations.
From an operational perspective, this vulnerability creates significant risk for systems that process untrusted tar archives, including web applications, backup systems, automated deployment tools, and file upload handlers. Attackers can exploit this weakness to overwrite critical system files, install malicious payloads, or disrupt normal system operations. The impact extends beyond simple file overwrites to include potential privilege escalation scenarios where attackers can manipulate system configuration files or replace executable components. This vulnerability directly relates to the CWE-22 weakness category, which describes improper limitation of a pathname to a restricted directory, commonly known as path traversal or directory traversal attacks.
The exploitation of CVE-2007-4559 aligns with several techniques documented in the MITRE ATT&CK framework under the File and Directory Permissions Modification tactic, specifically targeting the ability to write to arbitrary locations on the file system. Systems using Python applications that handle user-supplied tar archives are particularly vulnerable, including web applications that allow file uploads, automated backup and restore systems, and content delivery platforms. The vulnerability's persistence across multiple Python versions and its relationship to CVE-2001-1267 indicates a long-standing flaw in the tarfile module implementation that required extensive remediation efforts across the Python ecosystem.
Mitigation strategies for this vulnerability encompass both immediate code-level fixes and broader architectural security measures. The primary solution involves updating Python installations to versions that contain patched implementations of the tarfile module, typically those released after the vulnerability disclosure. Additionally, developers should implement proper input validation and sanitization when processing tar archives, including checking for and rejecting filenames containing directory traversal sequences. System administrators should also consider implementing file access controls and restricting write permissions for directories where archive extraction occurs. The vulnerability serves as a reminder of the importance of secure coding practices and the need for thorough security testing of file processing components, particularly those handling untrusted input data that could be manipulated to exploit path traversal weaknesses in application logic.