CVE-2021-37621 Explained : Impact and Mitigation

A denial of service vulnerability due to an infinite loop in Image::printIFDStructure in the Exiv2 library was discovered. Attackers could exploit this vulnerability in Exiv2 versions v0.27.4 and earlier to cause a denial of service by tricking users into running Exiv2 on a crafted image file. Here's what you need to know about CVE-2021-37621.

Understanding CVE-2021-37621

The vulnerability in Exiv2 library versions v0.27.4 and earlier could lead to a denial of service attack by causing an infinite loop when handling crafted image files. The bug is specifically triggered when printing the image ICC profile.

What is CVE-2021-37621?

Exiv2 is a C++ library used for manipulating image file metadata, and a bug in versions v0.27.4 and earlier triggers an infinite loop when printing metadata of a crafted image file's ICC profile, potentially leading to denial of service.

The Impact of CVE-2021-37621

The impact of this vulnerability is primarily a denial of service, where an attacker can crash the application by triggering the infinite loop through a crafted image file.

Technical Details of CVE-2021-37621

In Exiv2 versions v0.27.4 and earlier, the vulnerability arises from an infinite loop condition while printing image metadata, specifically the ICC profile.

Vulnerability Description

The vulnerability is due to a flaw in handling the image ICC profile printing operation, leading to an infinite loop.

Affected Systems and Versions

Exiv2 versions up to v0.27.4 are affected by this vulnerability.

Exploitation Mechanism

An attacker needs to trick users into running Exiv2 with the specific command line option (

-p C

) on a crafted image file to trigger the infinite loop.

Mitigation and Prevention

To mitigate the CVE-2021-37621 vulnerability, users and administrators are advised to take immediate steps and adopt long-term security practices.

Immediate Steps to Take

Update Exiv2 to version v0.27.5 or later to fix the vulnerability and prevent exploitation. Avoid running Exiv2 on untrusted or suspicious image files.

Long-Term Security Practices

Regularly update software components, use reputable image processing libraries, and educate users on safe image file handling practices.

Patching and Updates

Ensure timely application of software updates and security patches provided by Exiv2 to address known vulnerabilities and improve system security.