CVE-2013-4101 in Cryptocat
Summary
by MITRE
Cryptocat before 2.1.12 has a HTML Handling Weakness via Link Markup Decorator addLinks() Function
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Analysis
by VulDB Data Team • 02/01/2024
The vulnerability identified as CVE-2013-4101 affects Cryptocat versions prior to 2112, specifically targeting a critical HTML handling weakness within the addLinks() function responsible for link markup decoration. This flaw represents a significant security concern as it allows malicious actors to exploit the application's HTML processing capabilities through crafted link markup. The vulnerability stems from insufficient input validation and sanitization mechanisms within the link decoration functionality, creating a potential attack surface that could be leveraged for various malicious activities.
The technical implementation of this weakness occurs within the addLinks() function where user-provided content undergoes processing to add HTML markup for links. The flaw manifests when the application fails to properly sanitize or escape HTML characters in user input before incorporating them into the document structure. This inadequate handling allows attackers to inject malicious HTML or JavaScript code that gets executed within the context of the application's user interface. The vulnerability is particularly concerning because it operates at the presentation layer where users interact with content, making it difficult to distinguish between legitimate and malicious content. The weakness falls under CWE-79 which specifically addresses Cross-Site Scripting (XSS) vulnerabilities, where improper validation of user-supplied data leads to the execution of arbitrary code in the user's browser context.
The operational impact of this vulnerability extends beyond simple XSS attacks as it creates opportunities for more sophisticated exploitation techniques including session hijacking, credential theft, and phishing attacks. When users encounter maliciously crafted links within the Cryptocat application, the HTML injection can lead to unauthorized access to sensitive communications or compromise of user sessions. The vulnerability is particularly dangerous in the context of secure messaging applications where users trust the application to maintain confidentiality and integrity of their communications. Attackers could exploit this weakness to inject malicious scripts that capture keystrokes, steal session cookies, or redirect users to malicious websites. The attack surface is further expanded by the fact that this vulnerability exists in the client-side processing logic, meaning that even if server-side security measures are robust, client-side exploitation remains possible.
Mitigation strategies for CVE-2013-4101 require immediate implementation of proper input sanitization and output encoding mechanisms within the addLinks() function. The most effective approach involves implementing comprehensive HTML escaping routines that ensure all user-provided content is properly encoded before being incorporated into the document structure. Organizations should also implement Content Security Policy (CSP) headers to prevent the execution of unauthorized scripts and establish strict validation rules for all incoming content. Additionally, regular security updates and patch management procedures should be enforced to prevent similar vulnerabilities from being introduced in future versions. The remediation process should include thorough code review of all HTML processing functions and implementation of automated testing to detect similar issues before deployment. This vulnerability demonstrates the importance of input validation at all layers of application development and aligns with ATT&CK technique T1059.007 for Scripting, where attackers exploit application vulnerabilities to execute malicious code through client-side scripting. The fix should also include implementing proper error handling and logging mechanisms to detect and respond to potential exploitation attempts, ensuring that security monitoring systems can identify suspicious activities related to HTML injection attacks.