CVE-2006-1029 in Joomla
Summary
by MITRE
The cross-site scripting (XSS) countermeasures in class.inputfilter.php in Joomla! 1.0.7 allow remote attackers to cause a denial of service via a crafted mosmsg parameter to index.php with a malformed sequence of multiple tags, as demonstrated using "<<>AAA<><>", possibly due to nested or empty tags.
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Analysis
by VulDB Data Team • 07/08/2021
The vulnerability described in CVE-2006-1029 represents a critical cross-site scripting flaw in Joomla framework. The attack vector involves sending a specially crafted payload that contains malformed sequences of multiple HTML tags, with the demonstrated example of "<<>AAA<><>" showcasing how the system fails to properly sanitize nested or empty tags that could be used to circumvent the intended security controls.
The technical implementation of this vulnerability stems from the insufficient validation and sanitization logic within the input filter class. When Joomla! processes the mosmsg parameter through the class.inputfilter.php file, it fails to properly handle sequences that contain nested or empty HTML tags, allowing attackers to craft payloads that can bypass the XSS protection mechanisms. This flaw operates at the application layer and demonstrates a classic case of improper input validation where the system does not adequately account for malformed HTML structures that could be used to confuse or overwhelm the filtering logic. The vulnerability specifically affects the processing of HTML tag sequences that contain overlapping or malformed structures, creating a condition where the input filter either fails to detect malicious content or misinterprets the structure of the input data, leading to a potential denial of service condition.
The operational impact of this vulnerability extends beyond simple XSS exploitation to include significant denial of service capabilities that can severely impact the availability of the Joomla 1.0.7 and highlights the critical importance of robust input validation and sanitization mechanisms in web applications, particularly those handling user-supplied content.
Security practitioners should implement multiple layers of mitigation strategies to address this vulnerability effectively. The immediate solution involves upgrading to a patched version of Joomla! that contains proper input validation and sanitization logic to handle malformed HTML sequences appropriately. Additionally, administrators should consider implementing application firewalls or web application security controls that can detect and block suspicious input patterns before they reach the vulnerable application logic. The vulnerability aligns with CWE-79, which describes cross-site scripting flaws, and demonstrates characteristics that could be mapped to ATT&CK technique T1190, which involves exploiting vulnerabilities in web applications through input validation bypasses. Organizations should also implement comprehensive input sanitization policies that validate and normalize all user-supplied data, particularly parameters that are processed through HTML parsing mechanisms. Regular security assessments and penetration testing should be conducted to identify similar input validation gaps that could lead to similar or more severe vulnerabilities in the application stack.