CVE-2020-35653 : Security Advisory and Response

In Pillow before 8.1.0, a vulnerability known as PcxDecode allows a buffer over-read when processing a manipulated PCX file due to the reliance on a user-supplied stride value for buffer calculations.

Understanding CVE-2020-35653

Pillow software versions prior to 8.1.0 are susceptible to a buffer over-read vulnerability in the PcxDecode function.

What is CVE-2020-35653?

The vulnerability arises from the improper handling of user-supplied data during the decoding process of PCX files, leading to a buffer over-read issue.

The Impact of CVE-2020-35653

The vulnerability could be exploited by an attacker to read beyond the allocated memory, potentially exposing sensitive information or causing a denial of service.

Technical Details of CVE-2020-35653

Pillow software versions before 8.1.0 are affected by a buffer over-read vulnerability in the PcxDecode function.

Vulnerability Description

The issue occurs due to the trust placed on user-provided stride values for buffer calculations, which can result in reading beyond the intended memory boundaries.

Affected Systems and Versions

Product: Not applicable
Vendor: Not applicable
Versions: All versions before 8.1.0

Exploitation Mechanism

Attackers can craft malicious PCX files with manipulated stride values to trigger the buffer over-read, potentially leading to information exposure or service disruption.

Mitigation and Prevention

Immediate Steps to Take:

Update Pillow to version 8.1.0 or later to mitigate the vulnerability.
Avoid opening untrusted or unknown PCX files to reduce the risk of exploitation. Long-Term Security Practices:
Regularly update software and libraries to the latest versions to address known vulnerabilities.
Implement secure coding practices to validate and sanitize user input effectively.
Monitor security mailing lists and advisories for updates on vulnerabilities and patches.
Consider using security tools to scan for and identify potential vulnerabilities in software components.

Patching and Updates

Ensure timely installation of security patches and updates provided by Pillow to address the buffer over-read vulnerability in PcxDecode.