CVE-2022-29166 in matrix-appservice-irc
Summary
by MITRE • 05/06/2022
matrix-appservice-irc is a Node.js IRC bridge for Matrix. The vulnerability in node-irc allows an attacker to manipulate a Matrix user into executing IRC commands by having them reply to a maliciously crafted message. The vulnerability has been patched in matrix-appservice-irc 0.33.2. Refrain from replying to messages from untrusted participants in IRC-bridged Matrix rooms. There are no known workarounds for this issue.
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Analysis
by VulDB Data Team • 05/08/2022
The CVE-2022-29166 vulnerability affects the matrix-appservice-irc component, which serves as a Node.js-based IRC bridge facilitating communication between Matrix and IRC networks. This bridge enables users to participate in IRC channels through Matrix clients, creating a unified communication experience across both platforms. The vulnerability stems from a flaw in the node-irc library that handles IRC protocol communication, specifically in how it processes user input and command parsing within the bridging context. The issue manifests when a malicious actor crafts specially formatted messages that exploit the IRC bridge's command interpretation mechanism, potentially leading to unauthorized command execution within the IRC environment.
The technical flaw represents a command injection vulnerability that leverages the trust relationship between Matrix users and the bridged IRC network. When a Matrix user receives a maliciously crafted message containing IRC commands, the bridge fails to properly sanitize or validate the input before forwarding it to the IRC server. This allows attackers to manipulate the bridge into executing unintended IRC commands on behalf of the victim user, potentially leading to unauthorized actions such as channel joining, parting, messaging, or even server-level commands depending on the IRC server configuration and the user's privileges. The vulnerability operates at the application layer and can be classified as a command injection issue under CWE-77, specifically involving improper neutralization of special elements used in commands.
The operational impact of this vulnerability extends beyond simple command execution, as it can enable attackers to compromise IRC channel integrity and potentially access sensitive information within bridged environments. Matrix users who engage with untrusted participants in IRC-bridged rooms become vulnerable to this attack vector, where malicious actors can craft messages that appear legitimate but contain embedded IRC commands. The attack requires minimal technical expertise to execute and can be particularly effective in environments where users frequently interact with external participants or where automated bridge responses are enabled. This vulnerability undermines the security assumptions of the bridging mechanism and can lead to unauthorized access to IRC channels, disruption of services, and potential data exposure within the bridged communication environment.
Organizations and users should immediately update to matrix-appservice-irc version 0.33.2 or later to remediate this vulnerability, as no effective workarounds exist for this specific issue. The recommended mitigation strategy involves implementing strict message filtering and validation mechanisms within bridged rooms, particularly for messages originating from untrusted participants. Administrators should consider implementing additional security controls such as rate limiting, message content inspection, and user authentication verification before allowing command execution through the bridge. The vulnerability highlights the importance of proper input validation and sanitization in cross-platform communication bridges, aligning with ATT&CK technique T1059.001 for command and script injection. Security teams should also monitor for suspicious activity patterns in bridged rooms and implement logging mechanisms to detect potential exploitation attempts. The incident underscores the critical need for maintaining up-to-date software components and implementing defense-in-depth strategies when dealing with protocol bridging systems that connect disparate communication platforms.