CVE-2018-13879 in Rocket.Chat
Summary
by MITRE
A reflected XSS issue was discovered in the registration form in Rocket.Chat before 0.66. When one creates an account, the next step will ask for a username. This field will not save HTML control characters but an error will be displayed that shows the attempted username unescaped via packages/rocketchat-ui-login/client/username/username.js in packages/rocketchat-ui-login/client/username/username.html.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 04/06/2023
The vulnerability identified as CVE-2018-13879 represents a classic reflected cross-site scripting flaw within the Rocket.Chat collaboration platform, specifically affecting versions prior to 0.66. This security weakness manifests in the user registration process where the system fails to properly sanitize user input during error display operations. The vulnerability occurs when users attempt to register accounts and encounter validation errors related to username selection, creating an opportunity for malicious actors to inject harmful scripts into the application's response.
The technical implementation of this vulnerability stems from improper input sanitization within the client-side JavaScript and HTML components of the login interface. The error message display mechanism in packages/rocketchat-ui-login/client/username/username.js and the corresponding HTML template packages/rocketchat-ui-login/client/username/username.html fail to escape special HTML characters that users might input during the registration process. When validation fails, the system renders the user's attempted input directly into the error message without proper HTML escaping, allowing malicious payloads to execute in the context of other users' browsers.
This reflected XSS vulnerability operates under the Common Weakness Enumeration classification CWE-79, which specifically addresses cross-site scripting flaws where untrusted data is incorporated into web pages without proper validation or sanitization. The operational impact of this vulnerability extends beyond simple data theft, as it enables attackers to execute arbitrary JavaScript code in the browsers of other users who view the error messages. Attackers could potentially steal session cookies, redirect users to malicious sites, or perform actions on behalf of authenticated users within the Rocket.Chat environment.
The security implications of CVE-2018-13879 align with ATT&CK technique T1531, which focuses on establishing persistence through the use of malicious code execution in web applications. The vulnerability creates a persistent attack surface where malicious actors can craft usernames containing XSS payloads that remain undetected until they are displayed in error messages. This allows for the exploitation of the application's trust relationship with its users, as legitimate error messages become vehicles for malicious code delivery.
Mitigation strategies for this vulnerability should focus on implementing comprehensive input validation and output sanitization mechanisms throughout the application's user interface components. The fix requires proper HTML escaping of all user-supplied data before rendering it in error messages and other display contexts. Additionally, developers should implement Content Security Policy headers to limit the execution of inline scripts and establish a robust input validation framework that prevents potentially harmful characters from being processed as part of user input. The recommended remediation involves updating to Rocket.Chat version 0.66 or later where the vulnerability has been addressed through proper input sanitization and output encoding mechanisms.