CVE-2017-11517
📋 TL;DR
This vulnerability allows remote attackers to execute arbitrary code on affected Geutebrueck Gcore servers by sending a specially crafted HTTP GET request with an overly long URI. The stack-based buffer overflow in GCoreServer.exe can lead to complete system compromise. Organizations using Geutebrueck Gcore versions 1.3.8.42 or 1.4.2.37 are affected.
💻 Affected Systems
- Geutebrueck Gcore
📦 What is this software?
Gcore by Geutebrueck
Gcore by Geutebrueck
⚠️ Risk & Real-World Impact
Worst Case
Full remote code execution leading to complete system takeover, data exfiltration, lateral movement, and persistent backdoor installation.
Likely Case
Remote code execution allowing attackers to install malware, steal credentials, or use the system as a foothold for further attacks.
If Mitigated
Denial of service if exploit fails or crashes the service without achieving code execution.
🎯 Exploit Status
Exploit code is publicly available and requires no authentication. Simple HTTP request triggers the vulnerability.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Versions after 1.4.2.37
Vendor Advisory: https://www.geutebrueck.com/
Restart Required: Yes
Instructions:
1. Contact Geutebrueck support for updated version. 2. Backup configuration. 3. Install updated Gcore software. 4. Restart the Gcore service.
🔧 Temporary Workarounds
Network Segmentation
allIsolate Gcore servers from untrusted networks and internet access.
Web Application Firewall
allDeploy WAF to block HTTP requests with excessively long URIs.
🧯 If You Can't Patch
- Implement strict network access controls to limit exposure to trusted IPs only.
- Monitor for abnormal HTTP requests with long URIs and implement rate limiting.
🔍 How to Verify
Check if Vulnerable:
Check Gcore version in administration interface or examine GCoreServer.exe file properties.Check Version:
Check via Gcore web interface or examine file version of GCoreServer.exeVerify Fix Applied:
Verify installed version is newer than 1.4.2.37 and test with known exploit payloads in controlled environment.📡 Detection & Monitoring
Log Indicators:
- HTTP GET requests with unusually long URIs (>1024 characters)
- GCoreServer.exe crashes or abnormal termination
Network Indicators:
- HTTP requests to Gcore servers with URI length exceeding normal parameters
- Unusual outbound connections from Gcore servers
SIEM Query:
source="gcore.logs" AND (uri_length>1024 OR "buffer overflow" OR "access violation")