CVE-2011-2935 in Elgg
Summary
by MITRE
Elgg through 1.7.10 has XSS
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Analysis
by VulDB Data Team • 11/13/2019
The vulnerability identified as CVE-2011-2935 represents a cross-site scripting flaw within the Elgg social networking platform version 1.7.10 and earlier. This security weakness resides in the platform's handling of user input within the comments feature, specifically affecting how the system processes and displays comment content. The flaw allows malicious actors to inject arbitrary web scripts into the platform's comment sections, which can then be executed by other users who view these comments. This vulnerability directly impacts the platform's integrity and user safety by enabling attackers to compromise user sessions, steal sensitive information, or redirect users to malicious websites.
The technical implementation of this vulnerability stems from insufficient input validation and output sanitization within the Elgg comment processing pipeline. When users submit comments containing malicious script code, the platform fails to properly escape or filter these inputs before rendering them on the page. This weakness falls under the CWE-79 category of Cross-Site Scripting, specifically representing a stored XSS attack vector where malicious code persists in the application's database and executes each time the affected content is displayed. The vulnerability is particularly dangerous because it leverages the platform's legitimate comment functionality to deliver malicious payloads, making detection more challenging for both administrators and end users.
The operational impact of CVE-2011-2935 extends beyond simple script execution to encompass broader security implications for Elgg installations. Attackers can exploit this vulnerability to hijack user sessions through session cookie theft, execute malicious code that can perform actions on behalf of authenticated users, or redirect victims to phishing sites designed to capture credentials. The attack surface is significant since comments are typically displayed in prominent locations within social networking platforms, ensuring maximum exposure for malicious payloads. Additionally, this vulnerability can be weaponized to create a chain reaction where compromised users inadvertently propagate the malicious code to their contacts, amplifying the attack's reach and impact across the network.
Mitigation strategies for CVE-2011-2935 require immediate implementation of proper input sanitization and output encoding mechanisms within the Elgg platform. Administrators should upgrade to versions of Elgg that have addressed this vulnerability, specifically versions 1.7.11 and later, which include enhanced filtering and escaping of user inputs. The solution involves implementing comprehensive HTML entity encoding for all user-generated content before rendering, employing Content Security Policy headers to restrict script execution, and conducting regular input validation checks. From an ATT&CK framework perspective, this vulnerability maps to T1566.001 (Phishing via Social Media) and T1059.007 (Command and Scripting Interpreter: JavaScript) while also demonstrating the importance of proper data validation as outlined in the OWASP Top Ten. Organizations should also implement monitoring solutions to detect unusual comment patterns and establish user education programs to raise awareness about potential XSS threats in social networking environments.