CVE-2012-2243 in Mahara
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in Mahara 1.4.x before 1.4.5 and 1.5.x before 1.5.4 allows remote attackers to inject arbitrary web script or HTML by uploading an XML file with the xhtml extension, which is rendered inline as script. NOTE: this can be leveraged with CVE-2012-2244 to execute arbitrary code without authentication, as demonstrated by modifying the clamav path.
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Analysis
by VulDB Data Team • 12/20/2021
The vulnerability described in CVE-2012-2243 represents a critical cross-site scripting flaw affecting Mahara learning management systems version 1.4.x before 1.4.5 and 1.5.x before 1.5.4. This vulnerability operates through a sophisticated attack vector involving XML file uploads with xhtml extensions that are subsequently rendered inline as executable script content. The flaw falls under the CWE-79 category of Cross-Site Scripting, specifically representing a server-side XSS vulnerability where user-supplied content is improperly validated and sanitized before being rendered in web contexts. The vulnerability's exploitation requires an attacker to upload a malicious XML file with the xhtml extension, which the system then processes and renders inline, creating a persistent XSS condition that can be triggered when legitimate users access the affected content.
The operational impact of this vulnerability extends beyond traditional XSS limitations through its potential integration with CVE-2012-2244, creating a chained attack scenario that enables remote code execution without authentication. This combination demonstrates the dangerous escalation path available to attackers who can leverage the XSS vulnerability to manipulate system configurations, specifically targeting the clamav path modification as demonstrated in exploitation scenarios. The attack chain illustrates how seemingly isolated vulnerabilities can combine to create more severe security implications, with the XSS component serving as a prerequisite for executing the code execution vulnerability. This chaining mechanism aligns with ATT&CK technique T1203 - Exploitation for Client Execution, where attackers use web-based vulnerabilities to establish persistent access and execute arbitrary commands on affected systems.
The technical implementation of this vulnerability exploits the system's file validation and content rendering processes, particularly focusing on how XML files with xhtml extensions are handled during upload and display operations. When the system processes these files, it fails to properly sanitize the content before inline rendering, allowing attackers to embed malicious script code that executes within the context of other users' browsers. The vulnerability's persistence stems from the fact that once the malicious file is uploaded and stored, it remains active in the system's content repository, continuously serving as a vector for XSS attacks. This characteristic places the vulnerability in the ATT&CK framework's T1566 - Phishing with Malicious Attachments category, as it enables attackers to deliver malicious content through seemingly legitimate file upload mechanisms.
Security mitigations for this vulnerability require multiple defensive layers including strict input validation for file extensions and content types, comprehensive content sanitization before rendering, and proper access controls for file upload operations. System administrators should implement immediate patching to versions 1.4.5 and 1.5.4 where the vulnerability has been addressed through enhanced validation mechanisms and improved sanitization of uploaded content. The remediation process should include reviewing and strengthening the file upload validation logic, implementing proper MIME type checking, and establishing content security policies that prevent inline script execution. Additionally, organizations should consider implementing web application firewalls to detect and block suspicious file upload patterns, and establish monitoring procedures to identify unauthorized file uploads that may indicate exploitation attempts. The vulnerability's classification under CWE-79 and its exploitation through ATT&CK techniques emphasizes the need for comprehensive security controls that address both input validation and output sanitization aspects of web application security.