CVE-2021-37696 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 MassDM message. Issue is patched in commit 92325be650a6c17940cc52611797533ed95dbbe1. All users are advised to update to the current commit. As a workaround users may unload the MassDM cog or globally disable the `[p]massdm` command.
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Analysis
by VulDB Data Team • 08/16/2021
The vulnerability CVE-2021-37696 affects tmerc-cogs, an open source collection of plugins designed for the Red Discord bot framework. This particular flaw resides within the MassDM cog functionality which enables administrators to send mass direct messages to users within a Discord server. The security issue stems from insufficient input validation and access control mechanisms within the command processing logic. Attackers can exploit this vulnerability by crafting specially formatted MassDM messages that bypass normal permission checks and gain access to sensitive information that should be restricted to authorized administrators only. The flaw represents a critical authorization bypass vulnerability that undermines the security model of the Discord bot plugin ecosystem.
The technical implementation of this vulnerability involves a flaw in how the MassDM cog processes user commands and validates permissions. When users submit MassDM commands, the system fails to properly verify that the requesting user possesses the necessary administrative privileges before executing sensitive operations. This allows any authenticated user within the Discord server to craft malicious payloads that can trigger the execution of privileged functions. The vulnerability specifically manifests when the command parser does not adequately sanitize or validate the command parameters, enabling attackers to manipulate the execution flow and access information that should remain confidential. This type of flaw aligns with CWE-284, which describes improper access control mechanisms, and represents a classic case of privilege escalation through command injection or manipulation.
The operational impact of this vulnerability extends beyond simple information disclosure, as it creates a pathway for potential abuse of the Discord bot infrastructure. An attacker who exploits this vulnerability could access user data, server configurations, or other sensitive information that might be processed by the MassDM functionality. The attack surface is particularly concerning because Discord bots often serve as central communication hubs for communities and may contain access to sensitive data or administrative controls. The vulnerability affects all users of the tmerc-cogs collection who have not updated to the patched version, making it a widespread concern for Discord server administrators who rely on these plugins for automated messaging operations. This issue demonstrates how seemingly simple command processing functions can create significant security risks when proper access controls are not implemented.
The recommended remediation approach involves updating to the patched commit 92325be650a6c17940cc52611797533ed95dbbe1 which implements proper input validation and access control checks for the MassDM command functionality. System administrators should immediately apply this update to all instances where the tmerc-cogs plugins are deployed. As a temporary workaround, users can mitigate the risk by unloading the MassDM cog entirely or disabling the `[p]massdm` command globally through the bot's configuration settings. Organizations should also implement monitoring for unauthorized access attempts to the MassDM functionality and establish regular security audits of their Discord bot plugin installations. This vulnerability highlights the importance of maintaining up-to-date security practices in open source software environments where plugins may introduce unexpected attack vectors. The issue demonstrates how the ATT&CK framework's privilege escalation techniques can be effectively implemented through poorly validated command processing in bot frameworks, emphasizing the need for comprehensive security testing of all user-facing commands in automated systems.