CVE-2023-2848
📋 TL;DR
CVE-2023-2848 is a Cross-Site WebSocket Hijacking vulnerability in Movim web chat platforms prior to version 0.22. Attackers can hijack WebSocket connections to perform unauthorized actions as authenticated users. All Movim instances running vulnerable versions are affected.
💻 Affected Systems
- Movim
📦 What is this software?
Movim by Movim
⚠️ Risk & Real-World Impact
Worst Case
Attackers can perform any action as authenticated users, including sending messages, accessing private conversations, modifying account settings, and potentially accessing sensitive data.
Likely Case
Attackers hijack WebSocket sessions to send unauthorized messages, access chat history, or perform limited account actions.
If Mitigated
With proper WebSocket origin validation, attackers cannot establish unauthorized connections, limiting impact to legitimate sessions only.
🎯 Exploit Status
Exploitation requires user interaction (visiting malicious site) but technical complexity is low once the attack vector is understood.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 0.22
Vendor Advisory: https://mov.im/node/pubsub.movim.eu/Movim/a2d05925-0427-4f3f-b777-d20571ddddff
Restart Required: Yes
Instructions:
1. Update Movim to version 0.22 or later. 2. Apply commits 49e2012aecdf918bb1d16f278fa9ff42fad29a9d and 96372082acd3e5d778a2522a60a1805bf2af31f6. 3. Restart the Movim service.
🔧 Temporary Workarounds
Implement WebSocket Origin Validation
allAdd proper Origin header validation for WebSocket connections to prevent cross-origin requests.
# Modify WebSocket server configuration to validate Origin headers
# Add origin validation in WebSocket handshake logic
🧯 If You Can't Patch
- Implement strict Content Security Policy (CSP) headers to restrict WebSocket connections
- Use Web Application Firewall (WAF) rules to block suspicious WebSocket handshakes
🔍 How to Verify
Check if Vulnerable:
Check Movim version: if version < 0.22, system is vulnerable. Review WebSocket implementation for missing Origin header validation.Check Version:
Check Movim configuration files or admin interface for version informationVerify Fix Applied:
Verify Movim version is 0.22 or later. Test WebSocket connections with different Origin headers to ensure proper validation.📡 Detection & Monitoring
Log Indicators:
- Multiple WebSocket connection attempts with different Origin headers
- Unauthorized WebSocket handshake attempts
Network Indicators:
- WebSocket connections originating from unexpected domains
- Cross-origin WebSocket requests without proper validation
SIEM Query:
websocket AND (origin NOT IN allowed_domains) OR (websocket_handshake_failed)🔗 References
- https://github.com/movim/movim/commit/49e2012aecdf918bb1d16f278fa9ff42fad29a9d
- https://github.com/movim/movim/commit/96372082acd3e5d778a2522a60a1805bf2af31f6
- https://mov.im/node/pubsub.movim.eu/Movim/a2d05925-0427-4f3f-b777-d20571ddddff
- https://github.com/movim/movim/commit/49e2012aecdf918bb1d16f278fa9ff42fad29a9d
- https://github.com/movim/movim/commit/96372082acd3e5d778a2522a60a1805bf2af31f6
- https://mov.im/node/pubsub.movim.eu/Movim/a2d05925-0427-4f3f-b777-d20571ddddff
