CVE-2023-40588 in Discourse
Summary
by MITRE • 09/15/2023
Discourse is an open-source discussion platform. Prior to version 3.1.1 of the `stable` branch and version 3.2.0.beta1 of the `beta` and `tests-passed` branches, a malicious user could add a 2FA or security key with a carefully crafted name to their account and cause a denial of service for other users. The issue is patched in version 3.1.1 of the `stable` branch and version 3.2.0.beta1 of the `beta` and `tests-passed` branches. There are no known workarounds.
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Analysis
by VulDB Data Team • 09/16/2023
The vulnerability identified as CVE-2023-40588 affects Discourse, an open-source discussion platform widely used for community forums and knowledge sharing systems. This security flaw resides in the platform's handling of two-factor authentication and security key management functionality, specifically within the authentication flow mechanisms. The issue represents a denial of service vulnerability that can be exploited by malicious actors to disrupt legitimate user access to the platform. The vulnerability impacts multiple release branches including the stable branch up to version 3.1.0 and the beta and tests-passed branches up to version 3.1.9, indicating a widespread exposure across different deployment scenarios.
The technical flaw stems from inadequate input validation and sanitization within the authentication key registration process. A malicious user can craft a specially formatted name for a 2FA device or security key that, when processed by the system, causes unexpected behavior leading to denial of service conditions for other legitimate users. This vulnerability operates at the application level and leverages the platform's authentication subsystem to create cascading failures that affect the broader user base. The flaw demonstrates poor security practices in handling user-provided data within critical authentication components, creating a condition where user input can be manipulated to disrupt service availability for other users. This type of vulnerability falls under CWE-20, which represents "Improper Input Validation" and aligns with ATT&CK technique T1499.004 for "Endpoint Denial of Service" within the adversary's tactics and techniques framework.
The operational impact of this vulnerability extends beyond simple service disruption to potentially compromise the overall integrity and availability of the Discourse platform. When exploited, the vulnerability can render the authentication system partially or fully non-functional for other users, effectively preventing them from accessing their accounts or participating in discussions. This creates a significant risk for organizations relying on Discourse for critical communication infrastructure, particularly those with large user bases where such denial of service conditions can cascade and affect business operations. The vulnerability affects not just individual user accounts but can potentially disrupt platform-wide authentication services, making it a critical concern for administrators managing community platforms. The lack of known workarounds means that organizations cannot implement temporary mitigations while awaiting patches, increasing the risk exposure during the vulnerability window.
The remediation for this vulnerability requires immediate deployment of the patched versions, specifically version 3.1.1 for the stable branch and version 3.2.0.beta1 for the beta and tests-passed branches. Organizations should prioritize updating their Discourse installations to prevent exploitation and maintain service availability for legitimate users. Security teams should monitor for any signs of exploitation attempts and ensure that all instances of the platform are updated to the patched versions. The vulnerability serves as a reminder of the critical importance of input validation in authentication systems and demonstrates how seemingly minor flaws in user interface components can lead to significant service disruption. Organizations should also implement monitoring for unusual authentication key registration patterns that might indicate exploitation attempts, as the vulnerability specifically targets the registration process for authentication devices rather than the authentication itself. This vulnerability underscores the necessity of comprehensive security testing for all user-facing input mechanisms, particularly those within security-critical subsystems such as authentication and authorization services.