CVE-2021-25831 Explained : Impact and Mitigation
Learn about CVE-2021-25831, a critical file extension vulnerability in ONLYOFFICE DocumentServer core module allowing remote code execution. Find out about impacts, affected versions, and mitigation steps.
A file extension handling issue in the core module of ONLYOFFICE DocumentServer v4.0.0-9-v5.6.3 allows remote code execution when converting crafted files from PPTT to PPTX format.
Understanding CVE-2021-25831
This CVE identifies a vulnerability in ONLYOFFICE DocumentServer that enables remote attackers to execute arbitrary code by exploiting a file conversion issue.
What is CVE-2021-25831?
CVE-2021-25831 is a security flaw in the core module of ONLYOFFICE DocumentServer that can be triggered by converting a maliciously crafted file from PPTT to PPTX, leading to remote code execution.
The Impact of CVE-2021-25831
The impact of this vulnerability is significant as it allows remote attackers to take control of the DocumentServer by exploiting file extension handling issues in the core module.
Technical Details of CVE-2021-25831
This section provides detailed technical information about the vulnerability.
Vulnerability Description
The vulnerability arises from improper file extension handling in the core module of ONLYOFFICE DocumentServer, specifically in the conversion process from PPTT to PPTX.
Affected Systems and Versions
The affected versions range from v4.0.0-9 to v5.6.3 of ONLYOFFICE DocumentServer.
Exploitation Mechanism
To exploit CVE-2021-25831, an attacker needs to submit a specially crafted file for conversion from PPTT to PPTX. By exploiting this alongside other string handling bugs, attackers can achieve remote code execution.
Mitigation and Prevention
Protect your systems against CVE-2021-25831 using the following strategies.
Immediate Steps to Take
Immediately update to a patched version of ONLYOFFICE DocumentServer to mitigate the risk of exploitation.
Long-Term Security Practices
Implement strict file handling policies, conduct regular security assessments, and educate users on safe file practices to enhance overall security posture.
Patching and Updates
Regularly apply security patches released by ONLYOFFICE and stay informed about new updates to address vulnerabilities like CVE-2021-25831.