CVE-2023-7113 in Mattermost
Summary
by MITRE • 12/29/2023
Mattermost version 8.1.6 and earlier fails to sanitize channel mention data in posts, which allows an attacker to inject markup in the web client.
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Analysis
by VulDB Data Team • 01/21/2024
The vulnerability identified as CVE-2023-7113 affects Mattermost versions 8.1.6 and earlier, representing a critical security flaw in the platform's handling of channel mention data within posts. This issue stems from inadequate input sanitization mechanisms that fail to properly process and validate user-generated content containing channel references. The flaw specifically manifests when the system processes channel mentions in posts, allowing malicious actors to exploit the insufficient data sanitization to inject arbitrary markup elements into the web client interface.
The technical implementation of this vulnerability resides in the web client's rendering pipeline where channel mention data is processed without proper HTML escaping or markup validation. When users create posts containing channel references, the system should sanitize these mentions to prevent cross-site scripting attacks. However, the current implementation fails to adequately filter or escape special characters that could be interpreted as HTML markup, enabling attackers to inject malicious content that gets rendered in the web interface. This represents a classic cross-site scripting vulnerability that operates at the client-side rendering layer rather than server-side processing.
The operational impact of this vulnerability extends beyond simple markup injection, as it creates potential vectors for more sophisticated attacks including session hijacking, credential theft, and persistent malicious content delivery. An attacker could craft posts containing channel mentions that, when viewed by other users, execute malicious JavaScript code or display misleading information. The vulnerability affects all users who have access to the Mattermost platform, particularly those who view posts containing channel mentions, making it a widespread concern for organizations relying on the platform for communication. The attack surface is broad since channel mentions are commonly used features in team collaboration platforms, increasing the likelihood of exploitation.
Organizations affected by this vulnerability should prioritize immediate patching to version 8.1.7 or later, which contains the necessary sanitization fixes. Additionally, security teams should implement network-level monitoring to detect unusual post creation patterns that might indicate exploitation attempts. The vulnerability aligns with CWE-79, which addresses cross-site scripting flaws, and maps to ATT&CK technique T1566 for social engineering through malicious content injection. Mitigation strategies should include enhanced input validation, regular security assessments of web client rendering components, and user education regarding the risks of viewing untrusted content within collaborative platforms. Organizations should also consider implementing content security policies and regular penetration testing to identify similar vulnerabilities in their communication infrastructure.