CVE-2021-37697 in tmerc-cogs
Summary
by MITRE • 08/12/2021
tmerc-cogs are a collection of open source plugins for the Red Discord bot. A vulnerability has been found in the code that allows any user to access sensitive information by crafting a specific membership event message. Issue is patched in commit d63c49b4cfc30c795336e4fff08cba3795e0fcc0. As a workaround users may unload the Welcome cog.
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Analysis
by VulDB Data Team • 08/16/2021
The vulnerability identified as CVE-2021-37697 affects tmerc-cogs, which are open source plugins designed for the Red Discord bot platform. This issue represents a significant security flaw that undermines the integrity of user data within Discord server environments where these plugins are deployed. The Red Discord bot serves as a popular modular platform for server automation and community management, making the exposure of sensitive information through this vulnerability particularly concerning for administrators and users who rely on these tools for server operations and user engagement.
The technical flaw manifests through a specific vulnerability in how the Welcome cog plugin processes membership event messages. Attackers can exploit this weakness by crafting specially formatted messages that trigger unintended information disclosure mechanisms within the plugin's code execution flow. This particular vulnerability falls under the category of information disclosure flaws, which can be classified as CWE-200 according to the Common Weakness Enumeration standards. The vulnerability allows unauthorized access to sensitive data that should remain protected within the plugin's operational context, potentially exposing user membership details, server configurations, or other confidential information that users expect to remain private.
The operational impact of this vulnerability extends beyond simple data exposure, as it creates potential attack vectors for malicious actors seeking to gather intelligence about server membership patterns, user behavior, or system configurations. This information can be leveraged for social engineering attacks, targeted harassment, or more sophisticated penetration testing activities. The vulnerability's exploitation does not require elevated privileges, making it particularly dangerous as any user within the Discord server can potentially trigger the information disclosure. This aligns with ATT&CK technique T1082, which covers system information discovery, and demonstrates how seemingly benign plugin functionality can be weaponized for reconnaissance purposes.
The patch implemented in commit d63c49b4cfc30c795336e4fff08cba3795e0fcc0 addresses the core issue by properly sanitizing input parameters and implementing stricter validation of membership event messages. This fix ensures that only legitimate membership events trigger the appropriate information handling procedures while preventing crafted messages from accessing sensitive data paths. The recommended workaround of unloading the Welcome cog provides administrators with an immediate mitigation strategy that effectively disables the vulnerable functionality until a proper update can be deployed. This approach aligns with the principle of least privilege and demonstrates how security teams should prioritize immediate remediation when vulnerabilities are discovered in widely used open source components. Organizations using Red Discord bot plugins should conduct comprehensive security assessments of their deployed modules and ensure all plugins are regularly updated to prevent similar vulnerabilities from being exploited in their operational environments.