CVE-2024-4599
📋 TL;DR
A remote denial of service vulnerability in LAN Messenger version 3.4.0 allows an attacker to crash the service by sending a long string continuously over UDP. This affects users running the vulnerable version, potentially disrupting messaging services on local networks.
💻 Affected Systems
- LAN Messenger
⚠️ Manual Verification Required
This CVE does not have specific version information in our database, so automatic vulnerability detection cannot determine if your system is affected.
Why? The CVE database entry doesn't specify which versions are vulnerable (no version ranges provided by the vendor/NVD).
🔒 Custom verification scripts are available for registered users. Sign up free to download automated test scripts.
- Review the CVE details at NVD
- Check vendor security advisories for your specific version
- Test if the vulnerability is exploitable in your environment
- Consider updating to the latest version as a precaution
⚠️ Risk & Real-World Impact
Worst Case
Complete service outage of LAN Messenger, disrupting internal communication and productivity until service is restarted or patched.
Likely Case
Intermittent service crashes leading to unreliable messaging functionality and potential data loss in active conversations.
If Mitigated
Minimal impact if network controls block UDP traffic or the service is patched, with only minor disruptions.
🎯 Exploit Status
Exploitation requires sending crafted UDP packets, which is straightforward with basic networking tools, but no public proof-of-concept has been disclosed.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 3.4.1 or later
Vendor Advisory: https://www.incibe.es/en/incibe-cert/notices/aviso/denial-service-vulnerability-lan-messenger
Restart Required: Yes
Instructions:
1. Download the latest version from the official LAN Messenger website. 2. Install the update over the existing installation. 3. Restart the LAN Messenger service or the entire system to apply changes.
🔧 Temporary Workarounds
Block UDP Traffic to LAN Messenger
linuxConfigure firewall rules to block UDP traffic on the port used by LAN Messenger (default is 6666) to prevent exploitation.
sudo iptables -A INPUT -p udp --dport 6666 -j DROP
Disable LAN Messenger Service
linuxTemporarily disable the LAN Messenger service if patching is not immediately possible to mitigate risk.
sudo systemctl stop lan-messenger
sudo systemctl disable lan-messenger
🧯 If You Can't Patch
- Implement network segmentation to isolate LAN Messenger traffic and limit exposure to trusted internal hosts only.
- Monitor network traffic for unusual UDP packets to LAN Messenger ports and set up alerts for potential attack attempts.
🔍 How to Verify
Check if Vulnerable:
Check the installed version of LAN Messenger; if it is 3.4.0, the system is vulnerable.Check Version:
lan-messenger --version or check the application's about section in the GUI.Verify Fix Applied:
After updating, confirm the version is 3.4.1 or later and test service stability under normal UDP traffic.📡 Detection & Monitoring
Log Indicators:
- Log entries showing LAN Messenger service crashes or restarts, especially with error messages related to UDP handling.
Network Indicators:
- High volume of UDP packets to port 6666 with long string payloads, indicating potential exploitation attempts.
SIEM Query:
source="lan-messenger.log" AND ("crash" OR "error") OR dest_port=6666 AND protocol=UDP AND packet_size>1000