CVE-2020-27761 Explained : Impact and Mitigation

CVE-2020-27761 is a vulnerability in ImageMagick that could result in undefined behavior when processing crafted input files. This article provides insights into the nature of the vulnerability, its impact, technical details, and mitigation strategies.

Understanding CVE-2020-27761

ImageMagick's WritePALMImage() function in /coders/palm.c used size_t casts in calculations, potentially leading to issues with representable types.

What is CVE-2020-27761?

The vulnerability arises from the use of size_t casts in calculations within WritePALMImage(), which could cause values to exceed the range of representable type

unsigned long

when processing malicious input files.

The Impact of CVE-2020-27761

Red Hat Product Security classified this vulnerability as Low severity due to its potential to affect application availability without demonstrating specific impacts. ImageMagick versions before 7.0.9-0 are affected.

Technical Details of CVE-2020-27761

The technical aspects of the vulnerability include:

Vulnerability Description

The flaw in WritePALMImage() used size_t casts, leading to potential undefined behavior when processing crafted input files.

Affected Systems and Versions

Vendor: n/a
Product: ImageMagick
Affected Version: ImageMagick 7.0.9-0

Exploitation Mechanism

Crafted input files trigger the vulnerability by causing values to exceed the representable range of

unsigned long

.

Mitigation and Prevention

To address CVE-2020-27761, consider the following steps:

Immediate Steps to Take

Apply the patch that casts to

ssize_t

to mitigate the issue.

Long-Term Security Practices

Regularly update ImageMagick to the latest version to prevent known vulnerabilities.

Patching and Updates

Ensure timely installation of security updates for ImageMagick to protect against potential exploits.