CVE-2016-10006 in AntiSamy
Summary
by MITRE
In OWASP AntiSamy before 1.5.5, by submitting a specially crafted input (a tag that supports style with active content), you could bypass the library protections and supply executable code. The impact is XSS.
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Analysis
by VulDB Data Team • 10/12/2022
The vulnerability identified as CVE-2016-10006 affects the OWASP AntiSamy library version 1.5.4 and earlier, representing a critical security flaw that undermines the library's core purpose of preventing cross-site scripting attacks. This vulnerability stems from insufficient validation mechanisms within the library's HTML sanitization process, specifically when handling HTML tags that support style attributes with active content. The flaw allows attackers to craft malicious input that appears to comply with the library's security policies while actually containing executable code that bypasses the intended protection measures.
The technical implementation of this vulnerability exploits the library's handling of HTML elements that support style attributes, particularly when these elements contain active content such as javascript: protocols or other executable code patterns. When AntiSamy processes such inputs, it fails to properly validate or sanitize the style attribute content, enabling attackers to inject malicious scripts that would normally be blocked by the library's security controls. This represents a fundamental failure in the library's input validation logic, where the system's trust in certain HTML constructs leads to a bypass of its protective mechanisms. The vulnerability specifically targets the library's approach to handling style attributes that support dynamic content, creating a pathway for attackers to inject executable code that can be executed in the context of a victim's browser session.
The operational impact of this vulnerability extends beyond simple XSS exploitation, as it fundamentally compromises the security assurances that organizations rely upon when implementing AntiSamy for HTML sanitization. Attackers can leverage this vulnerability to execute arbitrary JavaScript code within the browser context of users who encounter the malicious content, potentially leading to session hijacking, data theft, or redirection to malicious sites. The vulnerability's severity is amplified by the fact that AntiSamy is widely used in enterprise applications, web frameworks, and security products, meaning that a successful exploitation could affect numerous systems simultaneously. This bypass of security controls undermines the entire purpose of using HTML sanitization libraries, as the protection mechanisms that organizations depend upon become ineffective against this specific attack vector.
Organizations should immediately upgrade to AntiSamy version 1.5.5 or later to remediate this vulnerability, as the fix addresses the core validation issues in how the library handles style attributes with active content. Security teams should also conduct comprehensive audits of their applications to identify any custom configurations or extensions that might be vulnerable to similar bypass techniques. The mitigation strategy should include implementing additional layers of security beyond HTML sanitization, such as content security policies, proper input validation at multiple points in the application stack, and regular security testing to identify potential bypasses. This vulnerability aligns with CWE-79, which describes cross-site scripting flaws, and represents a specific implementation weakness in the security controls that organizations should consider when evaluating their overall security posture. The ATT&CK framework categorizes this as a code injection technique, specifically targeting the execution of malicious code through web application vulnerabilities, making it a critical concern for organizations implementing web application security controls.