CVE-2023-3615
📋 TL;DR
The Mattermost iOS app fails to properly validate TLS server certificates during WebSocket connection initialization, allowing network attackers to perform man-in-the-middle attacks and intercept communications. This affects all Mattermost iOS app users connecting to Mattermost servers over untrusted networks.
💻 Affected Systems
- Mattermost iOS mobile application
📦 What is this software?
Mattermost by Mattermost
⚠️ Risk & Real-World Impact
Worst Case
Attackers intercept and manipulate all communications between the Mattermost iOS app and server, potentially accessing sensitive messages, files, and authentication credentials.
Likely Case
Attackers on the same network can intercept communications, read messages, and potentially inject malicious content into conversations.
If Mitigated
With proper network segmentation and certificate pinning, risk is limited to attackers with privileged network access.
🎯 Exploit Status
Requires network position to intercept TLS traffic; standard certificate validation bypass techniques apply.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check Mattermost security updates for specific version
Vendor Advisory: https://mattermost.com/security-updates
Restart Required: Yes
Instructions:
1. Update Mattermost iOS app from the App Store. 2. Verify the app version matches the patched version in the security advisory. 3. Restart the app to ensure new connections use proper certificate validation.
🔧 Temporary Workarounds
Use VPN for all connections
allForce all Mattermost iOS app traffic through a trusted VPN to prevent network interception.
Restrict to trusted networks
allOnly allow Mattermost iOS app usage on trusted, secured networks with proper network monitoring.
🧯 If You Can't Patch
- Disable Mattermost iOS app usage until patched
- Require all iOS users to connect via corporate VPN with certificate validation
🔍 How to Verify
Check if Vulnerable:
Check iOS app version in Mattermost settings; compare with patched version in security advisory.Check Version:
In Mattermost iOS app: Settings → About → VersionVerify Fix Applied:
Test TLS certificate validation by attempting to connect to a server with invalid certificate; connection should fail.📡 Detection & Monitoring
Log Indicators:
- Unexpected certificate validation failures
- Connection attempts to servers with invalid certificates
Network Indicators:
- Unencrypted WebSocket traffic
- TLS handshake anomalies
SIEM Query:
Search for iOS app connections to Mattermost servers without proper TLS validation events