CVE-2024-32045
📋 TL;DR
This vulnerability allows Mattermost users to link their playbook runs to private channels they don't have access to, bypassing intended access controls. It affects Mattermost installations running vulnerable versions, potentially exposing sensitive channel information to unauthorized users.
💻 Affected Systems
- Mattermost
📦 What is this software?
Mattermost Server by Mattermost
Mattermost Server by Mattermost
Mattermost Server by Mattermost
⚠️ Risk & Real-World Impact
Worst Case
Unauthorized users gain access to sensitive information in private channels, potentially exposing confidential discussions, files, or data that should be restricted to channel members.
Likely Case
Users accidentally or intentionally link playbook runs to private channels they shouldn't access, exposing limited channel information through the playbook interface.
If Mitigated
With proper monitoring and user training, impact is limited to occasional access violations that can be detected and corrected.
🎯 Exploit Status
Exploitation requires authenticated user access and playbook permissions. The vulnerability is in the access control logic when linking runs to channels.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 9.5.4, 9.6.2, 8.1.13 or later
Vendor Advisory: https://mattermost.com/security-updates
Restart Required: Yes
Instructions:
1. Backup your Mattermost installation and database. 2. Download the patched version from Mattermost downloads. 3. Stop Mattermost service. 4. Replace installation with patched version. 5. Restart Mattermost service. 6. Verify version is updated.
🔧 Temporary Workarounds
Disable Playbooks Plugin
allTemporarily disable the Playbooks plugin to prevent exploitation until patching is complete.
mmctl plugin disable playbooks
Restrict Playbook Permissions
allLimit playbook run creation permissions to trusted users only through System Console settings.
🧯 If You Can't Patch
- Implement strict monitoring of playbook run creation and channel linking activities
- Educate users about proper channel access protocols and report any suspicious linking activities
🔍 How to Verify
Check if Vulnerable:
Check Mattermost version via System Console > About or run: mattermost versionCheck Version:
mattermost versionVerify Fix Applied:
After patching, verify version is 9.5.4+, 9.6.2+, or 8.1.13+ and test that users cannot link playbook runs to private channels they don't belong to.📡 Detection & Monitoring
Log Indicators:
- Audit logs showing playbook runs linked to channels by non-members
- Access logs showing unauthorized channel access attempts
Network Indicators:
- Unusual API calls to channel linking endpoints from unauthorized users
SIEM Query:
source="mattermost" AND (event="playbook_run_linked" OR event="channel_access") AND user NOT IN channel_members