CVE-2013-4107 in Cryptocat
Summary
by MITRE
Cryptocat before 2.0.22: cryptocat.js handlePresence() has cross site scripting
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Analysis
by VulDB Data Team • 02/04/2024
The vulnerability identified as CVE-2013-4107 affects Cryptocat versions prior to 2.0.22 and resides in the cryptocat.js JavaScript file within the handlePresence() function. This represents a classic cross-site scripting vulnerability that allows malicious actors to inject arbitrary JavaScript code into the victim's browser session. The flaw occurs when the application fails to properly sanitize user-supplied input before incorporating it into dynamic web content, creating an avenue for attackers to execute malicious scripts in the context of the victim's browser.
The technical implementation of this vulnerability stems from insufficient input validation and output encoding within the handlePresence() function which processes presence notifications in the chat application. When users receive presence updates from other participants, the application directly incorporates this data into the web page without proper sanitization measures. This allows an attacker who can manipulate presence data to inject malicious JavaScript payloads that execute in the victim's browser context, potentially leading to session hijacking, data exfiltration, or further exploitation of the compromised session.
From an operational impact perspective, this vulnerability undermines the core security model of Cryptocat as a secure messaging application. The XSS flaw compromises the confidentiality and integrity of communications by enabling attackers to intercept and manipulate messages, steal session cookies, or redirect users to malicious sites. The vulnerability affects all users of affected versions regardless of their security awareness, as the attack can occur through legitimate presence notifications without requiring user interaction beyond normal application usage. This makes the vulnerability particularly dangerous in environments where users rely on the application for sensitive communications.
The vulnerability aligns with CWE-79 which categorizes cross-site scripting flaws as weaknesses in web applications where untrusted data is incorporated into web pages without proper validation or encoding. From an ATT&CK framework perspective, this vulnerability maps to T1566.001 (Phishing: Spearphishing Attachment) and T1059.007 (Command and Scripting Interpreter: JavaScript) as attackers can leverage the XSS to deliver malicious payloads and execute code in victim browsers. The impact severity is heightened by the fact that Cryptocat users typically trust the application for secure communications, making social engineering attacks more effective when combined with this XSS vulnerability. Organizations should implement immediate patching strategies and consider network monitoring for suspicious JavaScript payload delivery patterns.
Mitigation strategies include updating to Cryptocat version 2.0.22 or later which contains the necessary input sanitization fixes. Additionally, implementing content security policies can provide defense-in-depth measures to prevent execution of unauthorized scripts even if the vulnerability is exploited. Web application firewalls should be configured to detect and block suspicious JavaScript patterns in presence notification data. Regular security assessments of web applications should include thorough input validation testing to prevent similar vulnerabilities in other components. Security teams should also implement user education programs to raise awareness about the risks of unexpected presence notifications and the importance of keeping cryptographic tools updated.