CVE-2011-1953 in Post Revolution
Summary
by MITRE
Multiple cross-site scripting (XSS) vulnerabilities in common.php in Post Revolution before 0.8.0c-2 allow remote attackers to inject arbitrary web script or HTML via an attribute of a (1) P, a (2) STRONG, a (3) A, a (4) EM, a (5) I, a (6) IMG, a (7) LI, an (8) OL, a (9) VIDEO, or a (10) BLOCKQUOTE element.
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Analysis
by VulDB Data Team • 01/22/2018
The vulnerability identified as CVE-2011-1953 represents a critical cross-site scripting flaw in the Post Revolution content management system prior to version 0.8.0c-2. This vulnerability resides within the common.php file and demonstrates a classic input validation weakness that allows remote attackers to execute malicious scripts in the context of affected users' browsers. The flaw specifically targets multiple HTML elements including P, STRONG, A, EM, I, IMG, LI, OL, VIDEO, and BLOCKQUOTE tags, making it particularly dangerous as it can be exploited through various common web content elements. The vulnerability falls under CWE-79 which specifically addresses Cross-Site Scripting attacks, where improper validation of user-supplied data allows attackers to inject malicious scripts into web applications.
The technical implementation of this vulnerability stems from insufficient sanitization of HTML attributes within the Post Revolution system's content processing pipeline. When users submit content containing these specific HTML elements with malicious attributes, the application fails to properly escape or validate the input before rendering it to end users. This allows attackers to inject malicious JavaScript code or HTML content that executes in the browser context of legitimate users who view the affected content. The vulnerability is particularly concerning because it affects common HTML elements that are frequently used in web content creation, providing multiple attack vectors for exploitation. Attackers can leverage this flaw to steal session cookies, perform unauthorized actions on behalf of users, or redirect victims to malicious websites, all while appearing to originate from a trusted source.
The operational impact of CVE-2011-1953 extends beyond simple script injection, as it creates a persistent security risk for any website utilizing the vulnerable Post Revolution version. Users who browse content containing malicious payloads can unknowingly become compromised, potentially leading to account takeovers, data exfiltration, or further propagation of attacks within the affected system. The vulnerability's presence in common.php suggests it affects core functionality of the application, making it difficult to isolate and remediate without comprehensive system updates. Organizations relying on this CMS version face significant risk as the attack surface includes not just administrators but also regular users who may encounter malicious content in forums, comments, or user-generated content areas. The exploitation of this vulnerability directly aligns with ATT&CK technique T1566.001 which covers spearphishing attachments, and T1566.002 which involves spearphishing links, as attackers can craft malicious HTML content that appears legitimate but contains embedded malicious scripts.
Mitigation strategies for this vulnerability require immediate implementation of the vendor-provided security patch or upgrade to Post Revolution version 0.8.0c-2 or later. Organizations should implement comprehensive input validation and output encoding mechanisms to sanitize all user-supplied content before rendering it to browsers. The remediation process should include thorough code review of the common.php file to ensure all HTML attribute handling properly escapes special characters and validates input against whitelisted safe values. Security teams should also consider implementing web application firewalls with XSS detection capabilities as an additional protective layer. Regular security assessments and penetration testing should be conducted to identify similar vulnerabilities in other components of the web application stack. The vulnerability serves as a reminder of the critical importance of proper input validation and output encoding in web applications, aligning with security best practices outlined in OWASP Top Ten and NIST cybersecurity guidelines. Organizations should also establish robust patch management processes to ensure timely deployment of security updates across all systems and applications.