CVE-2021-30154 : Exploit Details and Defense Strategies

An issue was discovered in MediaWiki before 1.31.12 and 1.32.x through 1.35.x before 1.35.2. On Special:NewFiles, all the mediastatistics-header-* messages are output in HTML unescaped, leading to XSS.

Understanding CVE-2021-30154

This CVE refers to a vulnerability found in MediaWiki versions prior to 1.31.12 and 1.32.x through 1.35.x before 1.35.2. The issue arises from unescaped output of specific messages, allowing for potential cross-site scripting (XSS) attacks.

What is CVE-2021-30154?

CVE-2021-30154 identifies a security flaw in MediaWiki that could be exploited by an attacker to inject malicious scripts into web pages viewed by users, leading to various cyber threats.

The Impact of CVE-2021-30154

The impact of this CVE includes the possibility of unauthorized access to sensitive data, cookie theft, session hijacking, and other malicious activities that could compromise the security and integrity of a system.

Technical Details of CVE-2021-30154

The technical details of this CVE include:

Vulnerability Description

The vulnerability stems from the unescaped output of certain messages on the Special:NewFiles page in affected versions of MediaWiki, enabling attackers to execute arbitrary scripts through XSS.

Affected Systems and Versions

MediaWiki versions prior to 1.31.12 and 1.32.x through 1.35.x before 1.35.2 are affected by this security issue.

Exploitation Mechanism

Attackers can exploit this vulnerability by injecting malicious scripts disguised as mediastatistics-header-* messages, which are then executed when viewed by users, potentially compromising user data and system security.

Mitigation and Prevention

To address CVE-2021-30154, consider the following:

Immediate Steps to Take

Update MediaWiki to versions 1.31.12 or 1.35.2 to mitigate the vulnerability.
Monitor web traffic for any suspicious activity and unauthorized script executions.

Long-Term Security Practices

Implement proper input validation and output encoding to prevent XSS attacks.
Regularly update and patch software to eliminate known vulnerabilities and enhance system security.

Patching and Updates

Stay informed about security advisories and promptly apply patches released by MediaWiki to safeguard against potential exploits of CVE-2021-30154.