CVE-2019-20907 : Vulnerability Insights and Analysis
Learn about CVE-2019-20907, a Python vulnerability allowing an adversary to trigger an endless loop via a TAR archive. Find mitigation steps and updates here.
CVE-2019-20907 is a vulnerability that allows an adversary to create a TAR archive triggering an endless loop when opened by tarfile.open in Python up to version 3.8.3 due to header validation absence in _proc_pax of Lib/tarfile.py.
Understanding CVE-2019-20907
What is CVE-2019-20907?
The vulnerability enables an attacker to craft a TAR archive that causes an infinite loop when accessed by tarfile.open in Python versions up to 3.8.3.
The Impact of CVE-2019-20907
The exploit can lead to denial of service (DoS) attacks by consuming system resources indefinitely.
Technical Details of CVE-2019-20907
Vulnerability Description
The absence of header validation in _proc_pax of Lib/tarfile.py allows the creation of a malicious TAR archive triggering an endless loop.
Affected Systems and Versions
- Vendor: n/a
- Product: n/a
- Versions: All versions up to Python 3.8.3
Exploitation Mechanism
An adversary can create a specially crafted TAR archive to exploit the lack of header validation, causing an infinite loop when opened by tarfile.open.
Mitigation and Prevention
Immediate Steps to Take
- Update Python to version 3.8.4 or later to mitigate the vulnerability.
- Avoid opening TAR archives from untrusted sources.
Long-Term Security Practices
- Regularly update Python and other software to the latest versions.
- Implement input validation and sanitization in applications handling TAR archives.
Patching and Updates
Apply patches provided by Python to address the header validation issue and prevent the exploit.