CVE-2018-12336
📋 TL;DR
CVE-2018-12336 is a critical vulnerability in ECOS Secure Boot Stick 5.6.5 that contains an undocumented factory backdoor providing remote root SSH access. This allows attackers to extract confidential information from affected devices. Organizations using ECOS SBS 5.6.5 for secure boot operations are affected.
💻 Affected Systems
- ECOS Secure Boot Stick (SBS)
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete compromise of secure boot infrastructure, extraction of all confidential data including cryptographic keys, and potential persistence for future attacks on the entire network.
Likely Case
Unauthorized access to sensitive information stored on the device, including security credentials and configuration data that could be used for further attacks.
If Mitigated
Limited impact if SSH access is blocked at network boundaries and devices are isolated from sensitive systems.
🎯 Exploit Status
The backdoor provides direct SSH access without authentication, making exploitation trivial for anyone who discovers the access method.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Versions after 5.6.5
Vendor Advisory: https://telematik.prakinf.tu-ilmenau.de/ecos-sbs/advisory.html
Restart Required: Yes
Instructions:
1. Contact ECOS vendor for updated firmware. 2. Backup current configuration. 3. Flash updated firmware to all affected devices. 4. Verify SSH backdoor is removed. 5. Restore configuration if needed.
🔧 Temporary Workarounds
Network Isolation
linuxBlock SSH access to affected devices at network boundaries
iptables -A INPUT -p tcp --dport 22 -j DROP
firewall-cmd --permanent --add-rich-rule='rule family="ipv4" source address="0.0.0.0/0" port port="22" protocol="tcp" reject'
SSH Service Disable
linuxDisable SSH service on affected devices if not required
systemctl stop sshd
systemctl disable sshd
🧯 If You Can't Patch
- Isolate affected devices in separate VLAN with strict access controls
- Implement network monitoring and IDS/IPS rules to detect SSH backdoor access attempts
🔍 How to Verify
Check if Vulnerable:
Check device firmware version and attempt SSH connection using known backdoor credentials if documented in advisoryCheck Version:
cat /etc/ecos-version or check device management interfaceVerify Fix Applied:
Verify firmware version is updated beyond 5.6.5 and test that SSH backdoor access no longer works📡 Detection & Monitoring
Log Indicators:
- Unexpected SSH connections to port 22
- Root SSH access from unknown sources
- Failed authentication attempts followed by successful backdoor access
Network Indicators:
- SSH traffic to ECOS SBS devices from unexpected sources
- Patterns matching known backdoor exploitation
SIEM Query:
source="ssh.log" AND (dest_ip="ECOS_DEVICE_IP" OR user="root") AND action="accepted"