CVE-2005-0945 in ACS Blog
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in ACS Blog 1.1.1 allows remote attackers to inject arbitrary web script or HTML via onmouseover or onload events in (1) img, (2) link, or (3) mail tags.
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Analysis
by VulDB Data Team • 06/15/2024
The vulnerability described in CVE-2005-0945 represents a critical cross-site scripting flaw within ACS Blog version 1.1.1 that exposes web applications to remote code execution through malicious script injection. This vulnerability specifically targets the handling of HTML attributes within image, link, and mail tags, creating an attack surface where malicious actors can exploit user trust to execute unauthorized scripts. The flaw stems from inadequate input validation and sanitization of user-supplied content, particularly when processing HTML elements that support event handlers such as onmouseover and onload. These event attributes are commonly used to define actions that execute when users interact with web elements, making them prime targets for exploitation in XSS attacks. The vulnerability allows attackers to inject malicious scripts that can steal session cookies, redirect users to malicious sites, or perform other unauthorized actions on behalf of authenticated users. This type of vulnerability falls under CWE-79 which specifically addresses Cross-Site Scripting flaws in software applications, representing one of the most prevalent and dangerous web application security issues. The attack vector leverages the principle of trust that users place in web applications, where legitimate content is processed and displayed without proper sanitization of potentially malicious attributes.
The technical implementation of this vulnerability occurs when the ACS Blog application fails to properly filter or escape HTML attributes before rendering user-provided content. When an attacker crafts malicious input containing onmouseover or onload event handlers within img, link, or mail tags, the application processes this content without adequate security measures. The flaw exists because the application does not validate the attributes associated with these HTML elements, allowing attackers to inject script code that executes in the context of other users' browsers. This particular variant of XSS is classified as stored XSS when the malicious content is permanently stored on the server and then served to other users, or as reflected XSS when the malicious script is immediately reflected back to users through the application. The vulnerability demonstrates poor input validation practices and highlights the critical need for proper HTML sanitization techniques that remove or escape potentially dangerous attributes before content is rendered to end users. The attack can be executed through various means including email links, image tags with malicious attributes, or hyperlinks that contain event handlers, making it particularly insidious as it can be triggered through multiple vectors.
The operational impact of this vulnerability extends beyond simple script injection, potentially enabling sophisticated attacks that compromise user accounts and system integrity. Attackers can leverage this flaw to steal session tokens, perform unauthorized transactions, modify content, or redirect users to phishing sites that mimic legitimate applications. The vulnerability particularly affects users who trust the blog application and its content, as the malicious scripts execute automatically when users view pages containing the injected code. This can lead to widespread compromise of user accounts, data theft, and reputational damage to organizations hosting vulnerable applications. The attack scenario typically involves an attacker creating malicious blog posts or comments containing the injected scripts, which then execute whenever other users access the content. The vulnerability's impact is amplified when the blog application serves as a platform for user-generated content, as the attack surface increases with each user who can submit content. Organizations may face regulatory compliance issues, legal consequences, and loss of user confidence when such vulnerabilities are exploited. The vulnerability also demonstrates the broader challenge of web application security in environments where user input is heavily integrated into application functionality, requiring robust security controls throughout the application lifecycle.
Mitigation strategies for CVE-2005-0945 must address both immediate remediation and long-term security improvements in web application development practices. The primary fix involves implementing comprehensive input validation and output encoding mechanisms that sanitize all user-supplied content before it is processed or rendered. Applications should employ strict attribute filtering that removes or escapes dangerous HTML attributes such as onmouseover, onload, and other event handlers from user-generated content. Security measures should include the implementation of Content Security Policy headers to restrict script execution and prevent unauthorized code injection. Organizations should also deploy web application firewalls that can detect and block malicious script injection attempts. The solution requires developers to follow secure coding practices as outlined in OWASP Top Ten and NIST guidelines, particularly focusing on proper HTML sanitization and attribute validation. Regular security testing including dynamic application security testing and manual code reviews should be implemented to identify similar vulnerabilities. Additionally, implementing proper access controls and monitoring for unusual user behavior can help detect exploitation attempts. The vulnerability underscores the importance of defense-in-depth strategies that combine multiple security layers, including proper error handling, secure configuration management, and regular security updates to address known vulnerabilities. Organizations should also consider implementing automated security scanning tools that can identify similar XSS vulnerabilities across their web applications and ensure that all user input is properly validated and sanitized before processing.