CVE-2019-20916 Explained : Impact and Mitigation

The Python pip package, in versions prior to 19.2, has a vulnerability that allows Directory Traversal if a URL is provided in an install command. This vulnerability can be exploited to overwrite sensitive files like /root/.ssh/authorized_keys.

Understanding CVE-2019-20916

This CVE relates to a security issue in the Python pip package that enables Directory Traversal through a specific mechanism.

What is CVE-2019-20916?

The vulnerability in the Python pip package allows for Directory Traversal when a URL is included in an install command. By manipulating the Content-Disposition header, an attacker can overwrite critical files on the system.

The Impact of CVE-2019-20916

The vulnerability poses a significant risk as it can lead to unauthorized access and modification of sensitive files, potentially compromising the security of the system.

Technical Details of CVE-2019-20916

This section provides more in-depth technical insights into the CVE.

Vulnerability Description

The issue resides in the _download_http_url function within _internal/download.py, where the Content-Disposition header can contain ../ in a filename, enabling the traversal.

Affected Systems and Versions

Product: Python pip package
Versions: Prior to 19.2

Exploitation Mechanism

The vulnerability can be exploited by providing a malicious URL in an install command, allowing an attacker to perform Directory Traversal and overwrite sensitive files.

Mitigation and Prevention

Protecting systems from CVE-2019-20916 requires immediate actions and long-term security practices.

Immediate Steps to Take

Update Python pip to version 19.2 or newer to mitigate the vulnerability.
Avoid using URLs in install commands to reduce the risk of exploitation.

Long-Term Security Practices

Regularly monitor and update software packages to address security flaws promptly.
Implement proper input validation mechanisms to prevent malicious inputs.

Patching and Updates

Stay informed about security advisories and apply patches as soon as they are available to safeguard against known vulnerabilities.