How the CVE Works:
Mattermost versions 10.4.x (<= 10.4.2), 10.3.x (<= 10.3.3), and 9.11.x (<= 9.11.8) fail to properly restrict command execution in archived channels. This vulnerability allows authenticated users to execute slash commands within channels that have been archived. Normally, archived channels should be read-only, but due to this flaw, users can still interact with them, potentially leading to unauthorized actions or data manipulation. The issue arises from insufficient validation checks when processing commands in archived channels, enabling attackers to bypass intended restrictions.
DailyCVE Form:
Platform: Mattermost
Version: 10.4.x <= 10.4.2, 10.3.x <= 10.3.3, 9.11.x <= 9.11.8
Vulnerability: Command Execution in Archived Channels
Severity: Moderate
Date: Mar 21, 2025
What Undercode Say:
Exploitation:
1. Exploit Command Execution:
- Authenticate as a user with access to archived channels.
- Use slash commands (e.g.,
/kick,/invite) in archived channels to manipulate data or users. - Example: `/invite @user` in an archived channel to add unauthorized users.
2. Proof of Concept (PoC):
- Access an archived channel via API or UI.
- Send a POST request to execute commands:
curl -X POST -H "Authorization: Bearer <TOKEN>" -d '{"command":"/invite @user"}' https://<mattermost-server>/api/v4/channels/<channel-id>/commands
Protection:
1. Update Mattermost:
- Upgrade to patched versions: 10.4.3, 10.3.4, 9.11.9, or 10.5.1.
2. Restrict Access:
- Limit user permissions to archived channels.
- Use role-based access control (RBAC) to enforce read-only access.
3. Monitor Activity:
- Enable logging for command execution in archived channels.
- Use SIEM tools to detect unusual activity.
4. Code Fix:
- Implement validation checks in the command execution logic:
if channel.archived: raise Exception("Commands are disabled in archived channels.")
5. API Hardening:
- Validate channel status before processing commands in the API layer.
6. Automated Patching:
- Use tools like Ansible to automate updates:
</li> <li>name: Update Mattermost apt: name: mattermost state: latest
7. Security Audits:
- Regularly audit archived channels for unauthorized activity.
8. User Awareness:
- Educate users about the risks of executing commands in archived channels.
By following these steps, organizations can mitigate the risks associated with this vulnerability and ensure secure usage of Mattermost.
References:
Reported By: https://github.com/advisories/GHSA-4v65-xqcj-wpgg
Extra Source Hub:
Undercode
