CVE-2021-25636 Explained : Impact and Mitigation
Understand the impact, technical details, and mitigation steps for CVE-2021-25636, an Improper Certificate Validation vulnerability in LibreOffice allowing attackers to manipulate digital signatures.
A vulnerability in LibreOffice versions prior to 7.2.5 allowed an attacker to create a digitally signed ODF document with incorrect trust validation of signatures. Learn about the impact, technical details, and how to mitigate this CVE.
Understanding CVE-2021-25636
This section will cover what CVE-2021-25636 is, its impact, technical details, and mitigation steps.
What is CVE-2021-25636?
CVE-2021-25636 is an Improper Certificate Validation vulnerability in LibreOffice that allowed an attacker to manipulate document signatures to contain ambiguous KeyInfo children, resulting in incorrect validation of signatures.
The Impact of CVE-2021-25636
This vulnerability could lead to a bypass of signature validation, allowing malicious actors to create deceptive digitally signed documents, impacting the integrity and authenticity of signed ODF documents and macros within LibreOffice.
Technical Details of CVE-2021-25636
Let's explore the technical aspects of CVE-2021-25636 in more detail.
Vulnerability Description
The vulnerability arises from LibreOffice's mishandling of documentsignatures.xml or macrosignatures.xml streams, causing it to incorrectly validate signatures with ambiguous KeyInfo children, leading to trust validation issues.
Affected Systems and Versions
The Document Foundation LibreOffice 7.2 versions prior to 7.2.5 are affected by this vulnerability, impacting users who rely on digital signatures within LibreOffice.
Exploitation Mechanism
An attacker can exploit this vulnerability by crafting a digitally signed ODF document with manipulated KeyInfo children, causing LibreOffice to misidentify and validate the signature incorrectly.
Mitigation and Prevention
Discover the necessary steps to protect your systems and data from the risks associated with CVE-2021-25636.
Immediate Steps to Take
Users are advised to update LibreOffice to version 7.2.5 or later to mitigate the vulnerability and prevent potential exploitation by malicious actors.
Long-Term Security Practices
Employ best practices for secure document handling, verification of digital signatures, and maintaining up-to-date software to reduce the likelihood of similar vulnerabilities.
Patching and Updates
Stay informed about security advisories from LibreOffice and apply patches promptly to address known vulnerabilities and enhance the security of your systems.