CVE-2017-0370 in MediaWiki
Summary
by MITRE
Mediawiki before 1.28.1 / 1.27.2 / 1.23.16 contains a flaw were Spam blacklist is ineffective on encoded URLs inside file inclusion syntax's link parameter.
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Analysis
by VulDB Data Team • 02/27/2023
The vulnerability identified as CVE-2017-0370 affects MediaWiki versions prior to 1.28.1, 1.27.2, and 1.23.16, representing a critical security flaw in the software's spam protection mechanisms. This issue specifically targets the spam blacklist functionality that is designed to prevent malicious links from being embedded within wiki content. The flaw occurs when encoded URLs are used within file inclusion syntax's link parameter, allowing attackers to bypass the spam protection measures that should otherwise block malicious domains.
The technical nature of this vulnerability stems from insufficient input validation and sanitization within MediaWiki's parsing engine. When users attempt to include files using the wiki syntax such as [[File:example.jpg|link=http://malicious-domain.com]], the system fails to properly decode and validate the URL parameter before checking against the spam blacklist. This allows threat actors to encode malicious domains using URL encoding techniques such as %64%6f%6d%61%69%6e%2e%63%6f%6d, which when decoded reveal the actual malicious domain. The vulnerability specifically impacts the link parameter within file inclusion syntax, which is commonly used to create hyperlinks to external resources within wiki pages.
The operational impact of this vulnerability is significant as it undermines the fundamental security controls that wiki administrators rely upon to prevent spam and malicious link propagation. Attackers can now bypass spam filters to inject malicious links into wiki pages, potentially leading to phishing attacks, malware distribution, or the spread of malicious content across multiple wiki instances. This weakness is particularly dangerous in collaborative environments where multiple users contribute content, as it allows a single malicious actor to compromise the integrity of wiki content without requiring elevated privileges. The vulnerability also affects the trust model of wiki platforms, as users may unknowingly click on links that appear legitimate but are actually pointing to malicious destinations.
Organizations using affected MediaWiki versions should immediately implement the available patches and updates to address this vulnerability. The remediation process involves upgrading to MediaWiki version 1.28.1 or higher for the 1.28 release line, 1.27.2 for the 1.27 release line, or 1.23.16 for the 1.23 release line. Additionally, administrators should consider implementing additional security measures such as enhanced URL validation, regular monitoring of spam blacklist effectiveness, and user access controls to limit content creation privileges. The vulnerability aligns with CWE-20, which covers "Improper Input Validation," and can be categorized under ATT&CK technique T1190 for "Exploit Public-Facing Application" as it represents an attack vector that exploits weaknesses in web application security controls. Organizations should also consider implementing network-level protections and content filtering solutions as additional defensive measures against similar vulnerabilities in their wiki infrastructure.