CVE-2006-0735 in My Blog
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in BBcode.pm in M. Blom HTML::BBCode 1.04 and earlier, as used in products such as My Blog before 1.65, allows remote attackers to inject arbitrary Javascript via a javascript URI in an (1) img or (2) url BBcode tag.
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Analysis
by VulDB Data Team • 08/01/2017
The vulnerability identified as CVE-2006-0735 represents a critical cross-site scripting flaw within the HTML::BBCode module version 1.04 and earlier, specifically affecting the BBcode.pm component. This vulnerability manifests in products utilizing this library, most notably My Blog versions prior to 1.65, creating a significant security risk for web applications that process user-generated content through BBcode formatting. The flaw stems from insufficient input validation and sanitization of BBcode tags, particularly when handling javascript URIs within image and URL tags, allowing malicious actors to execute arbitrary JavaScript code within the context of users' browsers.
The technical implementation of this vulnerability occurs through the improper handling of javascript URIs within BBcode tags, specifically when processing img and url elements. When users submit content containing BBcode tags with javascript protocols in their source attributes, the vulnerable code fails to properly sanitize or escape these inputs before rendering them in the web page. This allows attackers to craft malicious BBcode that, when processed by the affected software, executes JavaScript code in the victim's browser context. The vulnerability is classified as a classic reflected XSS attack vector, where the malicious payload is embedded within the BBcode structure and executed when other users view the content.
The operational impact of this vulnerability extends beyond simple script execution, creating potential for serious security breaches including session hijacking, credential theft, and data exfiltration. Attackers can leverage this flaw to steal cookies, manipulate user sessions, or redirect victims to malicious sites that appear legitimate. The vulnerability affects the core functionality of content management systems that rely on BBcode for user-generated content, potentially compromising entire user bases if the affected applications are widely deployed. According to CWE-79, this represents a classic cross-site scripting weakness where untrusted data flows into web pages without proper validation or sanitization, making it a fundamental security flaw in web application development practices.
Mitigation strategies for this vulnerability require immediate patching of affected applications, specifically upgrading to My Blog version 1.65 or later, and ensuring the HTML::BBCode library is updated to a secure version. Organizations should implement comprehensive input validation and output encoding mechanisms, particularly when processing BBcode or similar markup languages. The implementation of Content Security Policy headers can provide additional defense-in-depth measures, while regular security audits of third-party libraries and modules should be conducted to identify similar vulnerabilities. According to ATT&CK framework technique T1566, this vulnerability aligns with the initial access phase where attackers exploit web application vulnerabilities to establish malicious code execution capabilities. Security teams should also consider implementing web application firewalls and monitoring for suspicious BBcode patterns, as this vulnerability demonstrates the critical importance of proper input sanitization in preventing client-side attacks.