CVE-2011-5191 in Pretty Link Lite plugin
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in pretty-bar.php in Pretty Link Lite plugin before 1.5.4 for WordPress allows remote attackers to inject arbitrary web script or HTML via the slug parameter, a different vulnerability than CVE-2011-5192.
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Analysis
by VulDB Data Team • 12/14/2021
The CVE-2011-5191 vulnerability represents a cross-site scripting flaw in the Pretty Link Lite WordPress plugin that existed prior to version 1.5.4. This vulnerability specifically affects the pretty-bar.php component of the plugin and enables remote attackers to execute malicious web scripts or HTML code through manipulation of the slug parameter. The flaw demonstrates a classic input validation weakness where user-supplied data is not properly sanitized before being processed and displayed within the web application context. Unlike CVE-2011-5192 which addressed a different vector, this vulnerability focuses exclusively on the slug parameter handling within the pretty-bar.php file, making it a distinct yet equally dangerous security weakness in the plugin's architecture.
The technical implementation of this vulnerability stems from inadequate sanitization of the slug parameter in the pretty-bar.php script. When a user submits data through the slug parameter, the plugin fails to properly validate or escape the input before incorporating it into dynamic web content. This allows an attacker to inject malicious JavaScript code or HTML markup that gets executed in the context of other users' browsers when they view pages containing the affected plugin functionality. The vulnerability operates under the Common Weakness Enumeration classification of CWE-79 - Improper Neutralization of Input During Web Page Generation, which specifically addresses the failure to properly escape or sanitize user input before rendering it in web pages. This weakness creates a persistent security risk where malicious payloads can be stored and executed across multiple user sessions.
The operational impact of CVE-2011-5191 extends beyond simple script injection, as it provides attackers with potential access to user sessions and sensitive data. When exploited, the vulnerability allows attackers to execute arbitrary code in victims' browsers, potentially enabling session hijacking, credential theft, or redirection to malicious sites. The attack vector requires no privileged access or authentication, making it particularly dangerous as it can be exploited by anyone who can interact with the affected WordPress site. The vulnerability affects the entire user base of affected WordPress installations using Pretty Link Lite plugin, creating widespread potential for exploitation. From an adversarial perspective, this flaw aligns with ATT&CK technique T1566.001 - Phishing: Spearphishing Attachment, as attackers could craft malicious links that would execute upon page load, or T1059.007 - Command and Scripting Interpreter: JavaScript, by leveraging the XSS capability to deliver malicious JavaScript payloads directly to target systems.
Mitigation strategies for this vulnerability primarily involve immediate patching of the Pretty Link Lite plugin to version 1.5.4 or later, which contains the necessary input validation and sanitization fixes. System administrators should also implement additional defensive measures including input validation at multiple layers, output escaping of all dynamic content, and regular security audits of installed WordPress plugins. The vulnerability highlights the importance of proper input sanitization and the principle of least privilege in web application development. Organizations should also consider implementing Content Security Policy headers to limit the execution of unauthorized scripts and employ web application firewalls to detect and block malicious input patterns. Regular monitoring of plugin repositories and security advisories remains crucial for maintaining the security posture of WordPress installations, as this vulnerability demonstrates how seemingly minor input handling flaws can create significant security risks in content management systems.