CVE-2022-39279 in discourse-chat
Summary
by MITRE • 10/07/2022
discourse-chat is a plugin for the Discourse message board which adds chat functionality. In versions prior to 0.9 some places render a chat channel's name and description in an unsafe way, allowing staff members to cause an cross site scripting (XSS) attack by inserting unsafe HTML into them. Version 0.9 has addressed this issue. Users are advised to upgrade. There are no known workarounds for this issue.
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Analysis
by VulDB Data Team • 10/30/2022
The discourse-chat plugin serves as an essential communication enhancement for the Discourse message board platform, providing real-time chat capabilities to users within discussion forums. This plugin extends the core functionality of Discourse by enabling users to engage in simultaneous conversations while maintaining context within the broader discussion threads. The vulnerability identified in versions prior to 0.9 represents a critical security flaw that undermines the platform's integrity and user safety. The issue specifically affects how the plugin handles user-generated content within chat channels, creating an environment where malicious actors can exploit the system's rendering mechanisms to execute unauthorized code.
The technical flaw manifests in the unsafe rendering of chat channel names and descriptions, where the plugin fails to properly sanitize or escape user input before displaying it to other users. This vulnerability directly maps to CWE-79, which describes Cross-Site Scripting flaws that occur when applications include untrusted data in web pages without proper validation or escaping mechanisms. The unsafe HTML rendering allows staff members or any user with appropriate permissions to inject malicious script code into channel metadata, which then executes in the browsers of other users who view these channels. This type of vulnerability creates a persistent threat vector that can be exploited to steal session cookies, redirect users to malicious sites, or perform actions on behalf of authenticated users.
The operational impact of this vulnerability extends beyond simple data corruption or user inconvenience, as it creates a potential attack surface for sophisticated social engineering campaigns. When staff members can inject malicious scripts, they gain the ability to manipulate the user experience in ways that could compromise entire user sessions or steal sensitive information. The vulnerability affects all users who interact with chat channels, making it particularly dangerous in environments where multiple administrators or trusted users have access to channel management features. The exploitation of this vulnerability can lead to account takeovers, unauthorized data access, and the potential for further lateral movement within the Discourse platform ecosystem. Organizations relying on discourse-chat for internal communications or community management face significant risks, as the vulnerability can be leveraged to establish persistent backdoors or exfiltrate information from the platform.
Mitigation strategies center exclusively on upgrading to version 0.9 or later, as no workarounds exist for this specific vulnerability. The upgrade process should be prioritized immediately, as the vulnerability has been acknowledged and patched by the development team. Organizations should implement comprehensive monitoring of their Discourse installations to ensure all instances have been updated and verify that no legacy versions remain operational. Security teams should also conduct thorough audits of existing chat channels to identify any potential malicious content that may have been injected prior to the patch deployment. Additionally, administrators should review and tighten permissions for channel management functions, as the vulnerability demonstrates that even trusted users with staff privileges can exploit the system. The incident underscores the importance of proper input validation and output escaping in web applications, aligning with ATT&CK technique T1566 which covers social engineering tactics that can be enhanced through exploitation of web application vulnerabilities. Regular security assessments and vulnerability scanning should be implemented to prevent similar issues from emerging in other plugins or components of the Discourse platform ecosystem.