CVE-2016-10893 in crayon-syntax-highlighter Plugin
Summary
by MITRE
The crayon-syntax-highlighter plugin before 2.8.4 for WordPress has multiple XSS issues via AJAX requests.
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Analysis
by VulDB Data Team • 11/27/2023
The crayon-syntax-highlighter plugin for WordPress prior to version 2.8.4 contained multiple cross-site scripting vulnerabilities that could be exploited through AJAX requests, representing a significant security risk for WordPress installations. This vulnerability classifies under CWE-79 as a failure to sanitize user input before incorporating it into dynamic content, specifically affecting the plugin's AJAX handling mechanisms that process user-submitted code syntax highlighting requests.
The technical flaw stems from insufficient validation and sanitization of input parameters within the plugin's AJAX endpoints. When users submitted code snippets for syntax highlighting through the plugin's interface, the application failed to properly escape or validate the content before processing it through AJAX requests. Attackers could craft malicious payloads containing script tags or other XSS vectors that would be executed in the context of other users' browsers when they viewed pages containing the vulnerable code blocks. The vulnerability was particularly dangerous because it leveraged the plugin's legitimate AJAX functionality to deliver malicious payloads without requiring authentication or direct exploitation of the WordPress core.
The operational impact of this vulnerability was substantial as it allowed attackers to execute arbitrary JavaScript code in the browsers of unsuspecting users who visited compromised WordPress sites. This could lead to session hijacking, credential theft, defacement of content, or redirection to malicious websites. The vulnerability affected all versions prior to 2.8.4, making it widespread across numerous WordPress installations that had not yet updated their plugins. Attackers could exploit this vulnerability by simply submitting malicious code through the plugin's interface, which would then be stored and executed whenever other users viewed the affected pages.
Mitigation strategies for this vulnerability required immediate plugin updates to version 2.8.4 or later, which contained proper input sanitization and output escaping mechanisms. Organizations should have implemented comprehensive security monitoring to detect unauthorized plugin modifications and maintained up-to-date WordPress core and plugin versions. The vulnerability also highlighted the importance of input validation and output escaping practices in web applications, aligning with ATT&CK technique T1059.007 for command and scripting interpreter and T1566.001 for credential access through phishing. Additionally, the incident demonstrated the critical need for regular security audits of third-party plugins and adherence to security best practices such as those outlined in the OWASP Top Ten project, particularly focusing on input validation and output encoding to prevent XSS vulnerabilities.
The vulnerability served as a reminder of how seemingly benign plugin functionalities could become attack vectors when proper security measures were not implemented. The AJAX request handling mechanism, while designed for legitimate functionality, became a pathway for malicious code execution due to inadequate security controls. This incident underscored the importance of security by design principles in web application development and the necessity of following established security frameworks to prevent such vulnerabilities from being introduced into production systems.