CVE-2011-5029 in Simple PHP Blog
Summary
by MITRE
Multiple cross-site scripting (XSS) vulnerabilities in Simple PHP Blog 0.7.0 and possibly earlier allow remote attackers to inject arbitrary web script or HTML via the (1) entry parameter to delete.php or (2) category parameter to index.php.
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Analysis
by VulDB Data Team • 01/17/2018
The vulnerability identified as CVE-2011-5029 represents a critical cross-site scripting flaw affecting Simple PHP Blog version 0.7.0 and potentially earlier releases. This vulnerability resides in the application's handling of user-supplied input parameters, specifically targeting two distinct entry points that process web requests without adequate sanitization or output encoding mechanisms. The flaw allows malicious actors to inject arbitrary web scripts or HTML content into the application's response, creating a persistent security risk for all users interacting with the vulnerable system.
The technical implementation of this vulnerability stems from insufficient input validation and output encoding practices within the Simple PHP Blog application. Attackers can exploit the vulnerability by crafting malicious payloads and submitting them through the entry parameter in delete.php or the category parameter in index.php. When the application processes these parameters without proper sanitization, the injected content becomes part of the web page response and executes in the context of other users' browsers. This occurs because the application fails to properly escape or encode user-provided data before rendering it within HTML output contexts, directly violating fundamental web security principles.
The operational impact of this vulnerability extends beyond simple data theft or defacement, as it enables attackers to execute arbitrary scripts in victims' browsers with the privileges of those users. This can lead to session hijacking, credential theft, redirection to malicious sites, or even privilege escalation within the application if users have administrative access. The vulnerability affects the entire user base of the vulnerable blog application, making it particularly dangerous as a single compromised input can affect multiple users simultaneously. The attack vector requires no special privileges or access to the system itself, making it easily exploitable by remote attackers.
From a cybersecurity framework perspective, this vulnerability maps directly to CWE-79 - Improper Neutralization of Input During Web Page Generation, which is a core weakness in web application security. The flaw also aligns with ATT&CK technique T1566.001 - Phishing, as attackers can use these XSS vulnerabilities to deliver malicious payloads through deceptive web content. Additionally, the vulnerability demonstrates poor input validation practices that violate security standards such as those outlined in OWASP Top Ten A03:2021 - Injection, specifically addressing the need for proper parameter validation and output encoding. Organizations should implement comprehensive input validation, output encoding, and Content Security Policy (CSP) headers to mitigate such vulnerabilities effectively.
Mitigation strategies for CVE-2011-5029 should include immediate patching of the Simple PHP Blog application to a version that properly sanitizes user input and implements proper output encoding. Organizations should also implement web application firewalls that can detect and block suspicious input patterns, establish strict input validation rules for all user-supplied parameters, and deploy CSP headers to limit the execution of unauthorized scripts. Regular security audits and penetration testing should be conducted to identify similar vulnerabilities in other web applications, while developers should follow secure coding practices including parameterized queries, input sanitization, and output encoding to prevent similar issues in future implementations.