CVE-2023-4494
📋 TL;DR
A stack-based buffer overflow vulnerability in Easy Chat Server 3.1 allows remote attackers to execute arbitrary code by sending an excessively long username string via a GET request to the register.ghp file. This affects users running the vulnerable version of the software, potentially leading to full system compromise.
💻 Affected Systems
- Easy Chat Server
📦 What is this software?
Easy Chat Server by Easy Chat Server Project
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete system takeover, data theft, or deployment of ransomware.
Likely Case
Remote code execution enabling attackers to install malware, pivot to other systems, or disrupt services.
If Mitigated
Limited impact if network segmentation or access controls block exploitation attempts.
🎯 Exploit Status
Exploitation involves sending a crafted GET request, making it relatively simple for attackers with network access.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: https://www.incibe.es/en/incibe-cert/notices/aviso/multiple-vulnerabilities-efs-software-products
Restart Required: No
Instructions:
Check the vendor advisory for updates; if no patch is available, consider upgrading to a newer version or applying workarounds.
🔧 Temporary Workarounds
Block Access to register.ghp
linuxRestrict network access to the vulnerable file using firewall rules or web server configurations.
iptables -A INPUT -p tcp --dport [chat-server-port] -m string --string "register.ghp" --algo bm -j DROP
Input Validation via Web Application Firewall
allDeploy a WAF to filter and block excessively long username strings in GET requests.
🧯 If You Can't Patch
- Isolate the Easy Chat Server from the internet and restrict internal network access to minimize exposure.
- Monitor network traffic for anomalous GET requests to register.ghp and implement intrusion detection systems.
🔍 How to Verify
Check if Vulnerable:
Check if Easy Chat Server version 3.1 is installed and accessible; test by sending a long username string to register.ghp and observing for crashes or errors.Check Version:
Check the server interface or configuration files for version information; on Linux, use 'ps aux | grep chat' or inspect installation directories.Verify Fix Applied:
Verify by ensuring the server no longer crashes or executes code when sent malicious requests, or confirm upgrade to a non-vulnerable version.📡 Detection & Monitoring
Log Indicators:
- Unusually long username strings in server logs
- Error messages related to buffer overflows or crashes in register.ghp requests
Network Indicators:
- GET requests to register.ghp with payloads exceeding typical username length
- Traffic spikes or anomalies from unknown IPs
SIEM Query:
source="chat_server.log" AND (uri="*register.ghp*" AND user_agent_length > 100)