CVE-2018-13878 in Rocket.Chat
Summary
by MITRE
An XSS issue was discovered in packages/rocketchat-mentions/Mentions.js in Rocket.Chat before 0.65. The real name of a username is displayed unescaped when the user is mentioned (using the @ symbol) in a channel or private chat. Consequently, it is possible to exfiltrate the secret token of every user and also admins in the channel.
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Analysis
by VulDB Data Team • 04/06/2023
The vulnerability described in CVE-2018-13878 represents a critical cross-site scripting flaw within the Rocket.Chat messaging platform that specifically affects versions prior to 0.65. This issue resides in the packages/rocketchat-mentions/Mentions.js file where the system fails to properly sanitize user input when displaying real names associated with usernames. The vulnerability manifests when users are mentioned using the @ symbol in either public channels or private chat conversations, creating an environment where malicious actors can exploit the lack of input validation and output escaping mechanisms. The flaw directly enables attackers to inject malicious scripts that execute within the context of other users' browsers, potentially compromising the entire communication platform.
The technical nature of this vulnerability aligns with CWE-79, which categorizes cross-site scripting as a code injection flaw where untrusted data is incorporated into web pages without proper validation or escaping. In this specific case, the system processes user-generated content containing real names without implementing appropriate HTML escaping or sanitization techniques before rendering the content in the browser. When a user's real name contains malicious script code, this code executes in the browser of any user who views the mention, creating a persistent threat vector. The vulnerability's severity is amplified by its ability to target secret tokens, which are typically used for authentication and session management within web applications, making it particularly dangerous for administrative accounts.
The operational impact of this vulnerability extends beyond simple script execution, as it enables comprehensive session hijacking and privilege escalation attacks. Attackers can craft malicious real names that contain scripts designed to steal cookies, session tokens, or other sensitive authentication information from users who view the mentions. This capability allows unauthorized individuals to impersonate legitimate users, potentially gaining administrative access to channels and the entire Rocket.Chat platform. The threat is particularly severe in environments where administrators frequently participate in channel discussions, as their elevated privileges could be compromised, leading to complete system takeover. The vulnerability affects all users within the scope of the mentioned conversations, making it a widespread threat that could impact thousands of users simultaneously.
Mitigation strategies for this vulnerability should include immediate patching to version 0.65 or later where the proper input sanitization has been implemented. Organizations should also implement additional security measures such as Content Security Policy headers to limit script execution capabilities, regular security audits of input validation mechanisms, and user education about potential social engineering attacks that might exploit such vulnerabilities. The fix typically involves implementing proper HTML escaping for all user-generated content before rendering it in the browser context, ensuring that special characters are properly encoded to prevent script execution. Security teams should also consider implementing web application firewalls to detect and block suspicious script injection attempts, while monitoring for unusual activity patterns that might indicate exploitation attempts. This vulnerability demonstrates the critical importance of input validation and output escaping in web applications, particularly in collaborative environments where user-generated content is extensively used.