CVE-2007-0231 in Movable Type
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in Movable Type (MT) 3.33, when nofollow is disabled and unmoderated comments are enabled, allows remote attackers to inject arbitrary web script or HTML via the Comments field.
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Analysis
by VulDB Data Team • 10/01/2017
The vulnerability identified as CVE-2007-0231 represents a critical cross-site scripting flaw in Movable Type version 3.33 that exploits specific configuration conditions to enable remote code execution through web browser manipulation. This vulnerability specifically targets the comment handling functionality of the content management system when certain security parameters are improperly configured. The flaw occurs when the nofollow attribute is disabled and unmoderated comments are enabled, creating a dangerous combination that allows attackers to inject malicious scripts directly into the comment submission process.
The technical implementation of this vulnerability stems from insufficient input validation and output encoding within the comment processing pipeline of Movable Type. When users submit comments containing malicious script code, the system fails to properly sanitize or escape the input before rendering it on the web page. This occurs because the nofollow attribute, which typically prevents search engines from following links and can help mitigate some XSS risks, is disabled, while the unmoderated comments feature allows all submissions to be immediately visible without any filtering or approval process. The combination of these two conditions creates an environment where attacker-controlled content can be directly executed in the context of other users' browsers.
The operational impact of this vulnerability extends beyond simple script injection, as it enables attackers to perform various malicious activities including session hijacking, credential theft, data exfiltration, and redirection to malicious sites. When a victim visits a page containing the malicious comment, their browser executes the injected script code in their current session context, potentially allowing the attacker to steal cookies, modify page content, or redirect users to phishing sites. The vulnerability affects the entire user base of the affected Movable Type installation, making it particularly dangerous for websites with active comment systems. This issue directly aligns with CWE-79, which categorizes cross-site scripting vulnerabilities as a fundamental web application security flaw, and maps to ATT&CK technique T1566.001 for initial access through malicious content injection.
Mitigation strategies for this vulnerability require immediate attention to the configuration settings of the Movable Type installation. System administrators should enable the nofollow attribute on all comment links to prevent the propagation of malicious links and implement comprehensive input validation for all comment fields. The most effective immediate fix involves disabling unmoderated comments or implementing robust content filtering mechanisms that sanitize all user input before storage and display. Additional protective measures include implementing proper output encoding for all dynamic content, utilizing content security policies to restrict script execution, and regularly updating the Movable Type software to patched versions. Organizations should also consider implementing web application firewalls to detect and block suspicious comment submissions, and establish monitoring procedures to identify potential exploitation attempts. The vulnerability serves as a critical reminder of the importance of proper input validation and the dangerous consequences of leaving security features disabled in web applications.