CVE-2024-54083
📋 TL;DR
This vulnerability in Mattermost allows authenticated users to send specially crafted posts that cause denial-of-service conditions for other users in specific channels. The attack affects webapp and mobile clients of users viewing the malicious post, potentially disrupting communication in affected channels. Organizations running vulnerable Mattermost versions are at risk.
💻 Affected Systems
- Mattermost Team Edition
- Mattermost Enterprise Edition
📦 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 disrupt communication in critical channels by making them unusable for all users, potentially affecting business operations that rely on Mattermost for coordination.
Likely Case
Disruption of specific channels where malicious posts are sent, causing temporary unavailability for users viewing those channels until they refresh or the post is removed.
If Mitigated
Minimal impact with proper monitoring and quick response to remove malicious posts, though some temporary disruption may still occur.
🎯 Exploit Status
Exploitation requires authenticated user access. The vulnerability is in client-side validation, making exploitation straightforward once the payload is known.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 10.1.3, 10.0.3, 9.11.5, 9.5.13
Vendor Advisory: https://mattermost.com/security-updates
Restart Required: Yes
Instructions:
1. Backup your Mattermost database and configuration. 2. Download the patched version from mattermost.com/download. 3. Stop the Mattermost service. 4. Replace the binary/files with the patched version. 5. Restart the Mattermost service. 6. Verify the version is updated.
🔧 Temporary Workarounds
Restrict posting permissions
allLimit who can post in sensitive channels to trusted users only
Monitor for unusual posts
allImplement monitoring for posts with unusual content or formatting
🧯 If You Can't Patch
- Implement strict access controls to limit who can post in critical channels
- Enable enhanced logging and monitoring for post creation events
🔍 How to Verify
Check if Vulnerable:
Check your Mattermost version against the affected versions list. If running 10.1.2 or earlier, 10.0.2 or earlier, 9.11.4 or earlier, or 9.5.12 or earlier, you are vulnerable.Check Version:
For Linux: mattermost version | grep Version. For web interface: System Console > About > Build Information.Verify Fix Applied:
After patching, verify the version shows 10.1.3+, 10.0.3+, 9.11.5+, or 9.5.13+ and test posting functionality in channels.📡 Detection & Monitoring
Log Indicators:
- Unusual post creation events
- Multiple users reporting client crashes in specific channels
- Error logs related to callProps validation
Network Indicators:
- Increased client reconnection attempts from users in specific channels
SIEM Query:
source="mattermost" AND (event="api_post_create" OR event="client_error") AND message="*callProps*"