CVE-2024-1039
📋 TL;DR
Gessler GmbH WEB-MASTER devices contain a restoration account with hard-coded credentials that cannot be changed. If exploited, attackers can gain administrative control over the web management interface. This affects all organizations using vulnerable WEB-MASTER devices.
💻 Affected Systems
- Gessler GmbH WEB-MASTER
📦 What is this software?
Web Master Firmware by Gesslergmbh
⚠️ Risk & Real-World Impact
Worst Case
Complete compromise of device management allowing configuration changes, firmware manipulation, or use as an attack pivot point within industrial control systems.
Likely Case
Unauthorized administrative access leading to configuration tampering, data exposure, or disruption of industrial operations.
If Mitigated
Limited impact if devices are isolated in air-gapped networks with strict access controls and monitoring.
🎯 Exploit Status
Exploitation requires only knowledge of the hard-coded credentials and network access to the device's web interface.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check vendor advisory for specific version
Vendor Advisory: https://www.cisa.gov/news-events/ics-advisories/icsa-24-032-01
Restart Required: Yes
Instructions:
1. Contact Gessler GmbH for updated firmware
2. Backup current configuration
3. Apply firmware update following vendor instructions
4. Verify restoration account is no longer accessible with default credentials
🔧 Temporary Workarounds
Network Segmentation
allIsolate WEB-MASTER devices in dedicated network segments with strict firewall rules
Access Control Lists
allImplement IP-based restrictions to limit management interface access to authorized administrative hosts only
🧯 If You Can't Patch
- Implement strict network segmentation to isolate vulnerable devices from untrusted networks
- Deploy network monitoring and intrusion detection specifically for authentication attempts to the restoration account
🔍 How to Verify
Check if Vulnerable:
Attempt to authenticate to the WEB-MASTER web interface using the known hard-coded restoration account credentialsCheck Version:
Check device firmware version via web interface or vendor-specific CLI commandsVerify Fix Applied:
Verify that restoration account authentication fails with default credentials after patching📡 Detection & Monitoring
Log Indicators:
- Failed authentication attempts to restoration account
- Successful logins from unusual IP addresses
- Configuration changes from restoration account
Network Indicators:
- HTTP/HTTPS traffic to management interface from unauthorized sources
- Authentication requests using known credential patterns
SIEM Query:
source="web-master-logs" AND (event_type="authentication" AND (username="restoration_account" OR username contains "restore"))