CVE-2024-41144
📋 TL;DR
This vulnerability in Mattermost allows a malicious remote attacker to create, update, or delete arbitrary posts in arbitrary channels when shared channels are enabled. It affects Mattermost installations with specific vulnerable versions where the shared channels feature is active. The issue stems from improper validation of synced posts in the shared channels functionality.
💻 Affected Systems
- Mattermost
📦 What is this software?
Mattermost Server by Mattermost
Mattermost Server by Mattermost
Mattermost Server by Mattermost
Mattermost Server by Mattermost
⚠️ Risk & Real-World Impact
Worst Case
An attacker could delete critical communications, post malicious content, or manipulate channel data across the entire Mattermost instance, potentially causing operational disruption or data integrity issues.
Likely Case
Malicious actors with access to shared channels could manipulate posts in channels they shouldn't have access to, potentially spreading misinformation or disrupting team communications.
If Mitigated
With proper network segmentation and access controls limiting shared channels to trusted entities, the impact would be limited to authorized users only.
🎯 Exploit Status
Exploitation requires access to shared channels functionality. The attacker needs to be part of a shared channel to exploit the vulnerability.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 9.9.1, 9.5.7, 9.7.6, 9.8.2
Vendor Advisory: https://mattermost.com/security-updates
Restart Required: Yes
Instructions:
1. Backup your Mattermost instance and database. 2. Download the patched version from Mattermost releases. 3. Stop the Mattermost service. 4. Replace the existing installation with the patched version. 5. Restart the Mattermost service. 6. Verify the version is updated.
🔧 Temporary Workarounds
Disable Shared Channels
allTemporarily disable the shared channels feature to prevent exploitation until patching can be completed.
Edit config.json and set 'EnableSharedChannels' to false
Restart Mattermost service
🧯 If You Can't Patch
- Disable shared channels feature immediately
- Implement strict access controls and monitoring for shared channel activities
🔍 How to Verify
Check if Vulnerable:
Check Mattermost version via System Console > About Mattermost. If version matches affected ranges and shared channels are enabled, the system is vulnerable.Check Version:
For Linux: grep 'Version' /opt/mattermost/config/config.json or check via Mattermost web interface System ConsoleVerify Fix Applied:
Verify version is updated to 9.9.1, 9.5.7, 9.7.6, or 9.8.2 or higher in System Console > About Mattermost.📡 Detection & Monitoring
Log Indicators:
- Unusual post creation/modification patterns in shared channels
- Posts appearing from unexpected users in channels
- Multiple post deletions in short timeframes
Network Indicators:
- Unusual API calls to post endpoints from shared channel sources
SIEM Query:
source='mattermost' AND (event='post_created' OR event='post_updated' OR event='post_deleted') AND channel_type='shared' AND user NOT IN [authorized_users]