CVE-2020-35474 : Exploit Details and Defense Strategies

In MediaWiki before 1.35.1, a vulnerability exists that could lead to XSS due to a specific combination of functions.

Understanding CVE-2020-35474

This CVE involves a security issue in MediaWiki that could potentially result in cross-site scripting (XSS) attacks.

What is CVE-2020-35474?

This CVE refers to a vulnerability in MediaWiki versions prior to 1.35.1. The issue arises from the use of Html::rawElement and Message::text, which can be exploited to execute XSS attacks by modifying the MediaWiki:recentchanges-legend-watchlistexpiry definition to output raw HTML.

The Impact of CVE-2020-35474

The vulnerability allows attackers to inject malicious scripts into web pages viewed by users, potentially leading to unauthorized actions or data theft.

Technical Details of CVE-2020-35474

This section provides more in-depth technical insights into the CVE.

Vulnerability Description

The vulnerability stems from the way Html::rawElement and Message::text are used in MediaWiki, enabling attackers to manipulate the output of MediaWiki:recentchanges-legend-watchlistexpiry to insert malicious HTML code.

Affected Systems and Versions

MediaWiki versions before 1.35.1 are affected by this vulnerability.

Exploitation Mechanism

Attackers can exploit this vulnerability by altering the MediaWiki:recentchanges-legend-watchlistexpiry definition to include malicious HTML, which is then rendered as raw HTML on the affected pages.

Mitigation and Prevention

Protecting systems from CVE-2020-35474 requires immediate actions and long-term security measures.

Immediate Steps to Take

Update MediaWiki to version 1.35.1 or later to mitigate the vulnerability.
Monitor and restrict changes to critical configuration files to prevent unauthorized modifications.

Long-Term Security Practices

Implement input validation and output encoding to prevent XSS attacks.
Regularly audit and review configurations and code for security vulnerabilities.

Patching and Updates

Apply security patches and updates promptly to address known vulnerabilities and enhance system security.