CVE-2007-3342 in Movable Type
Summary
by MITRE
Multiple cross-site scripting (XSS) vulnerabilities in Movable Type (MT) before 3.34 allow remote attackers to inject arbitrary web script or HTML via comments that have (1) a malformed SGML numeric character reference with a \0 (0x00) character in a javascript: URI or (2) an attribute in an element that lacks the > character at the end of the start tag, a different vulnerability than CVE-2007-0231.
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Analysis
by VulDB Data Team • 10/26/2017
The vulnerability described in CVE-2007-3342 represents a critical cross-site scripting weakness affecting Movable Type content management systems prior to version 3.34. This vulnerability manifests through two distinct attack vectors that exploit improper input validation and sanitization mechanisms within the comment processing functionality of the platform. The first vector involves malformed SGML numeric character references containing null characters within javascript: URIs, while the second exploits improperly closed HTML elements lacking the terminating greater-than symbol in start tags. Both vulnerabilities enable remote attackers to inject malicious web scripts or HTML code into the application's comment system, potentially compromising user sessions and data integrity.
The technical flaw stems from insufficient sanitization of user-supplied input within the comment processing pipeline of Movable Type. When comments containing these malformed inputs are processed, the system fails to properly validate or escape special characters before rendering them in the web interface. The first vulnerability specifically targets SGML parsing behavior where numeric character references with null bytes in javascript: URIs bypass normal sanitization routines, while the second vulnerability exploits HTML parsing inconsistencies where unclosed tags with missing closing brackets allow attackers to inject additional HTML attributes or scripts. This dual nature of the vulnerability demonstrates the complexity of input validation in web applications and the importance of comprehensive sanitization across all user-facing input points.
The operational impact of these vulnerabilities is significant as they enable attackers to execute arbitrary scripts in the context of affected users' browsers, potentially leading to session hijacking, credential theft, or data manipulation. Users who view compromised comments could have their browser sessions compromised, and attackers could leverage these vulnerabilities to perform actions on behalf of authenticated users. The vulnerabilities are particularly dangerous in blog environments where users frequently interact with comments from unknown sources, creating a wide attack surface for malicious actors. Additionally, the presence of these vulnerabilities in widely-used content management systems increases the potential for widespread exploitation across multiple websites.
Mitigation strategies should focus on implementing robust input validation and sanitization mechanisms throughout the comment processing pipeline. System administrators should immediately upgrade to Movable Type version 3.34 or later, which contains patches addressing both vulnerability vectors. Additional protective measures include implementing Content Security Policy headers, employing proper HTML escaping routines for all user-generated content, and conducting regular security audits of input handling mechanisms. The vulnerability aligns with CWE-79 (Cross-site Scripting) and follows patterns commonly associated with ATT&CK technique T1566.001 (Phishing with Social Engineering) where attackers leverage web application vulnerabilities to compromise user sessions and execute malicious code in victim browsers. Organizations should also consider implementing web application firewalls and regular security testing to identify similar vulnerabilities in other components of their web infrastructure.