CVE-2020-10539
📋 TL;DR
This vulnerability allows authentication bypass in Epikur software by using a hardcoded backdoor password. Any attacker who discovers this password can log in as any user without knowing their actual credentials. All Epikur installations before version 20.1.1 are affected.
💻 Affected Systems
- Epikur
📦 What is this software?
Epikur by Epikur
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise where attackers gain administrative access, steal sensitive data, modify configurations, and potentially pivot to other systems.
Likely Case
Unauthorized access to user accounts leading to data theft, privilege escalation, and potential lateral movement within the network.
If Mitigated
Limited impact with proper network segmentation, strong monitoring, and immediate credential rotation after detection.
🎯 Exploit Status
Exploitation requires only knowledge of the backdoor password. No special tools or skills needed beyond basic HTTP requests.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 20.1.1
Vendor Advisory: https://www.x41-dsec.de/lab/advisories/x41-2020-003-epikur
Restart Required: Yes
Instructions:
1. Download Epikur version 20.1.1 or later from official vendor sources. 2. Backup current installation and data. 3. Apply the update following vendor documentation. 4. Restart Epikur services. 5. Verify the fix by attempting to authenticate with the backdoor password (should fail).
🔧 Temporary Workarounds
Network Access Control
allRestrict network access to Epikur servers to only trusted IP addresses and networks.
# Example firewall rule (Linux iptables): iptables -A INPUT -p tcp --dport [EPIKUR_PORT] -s [TRUSTED_NETWORK] -j ACCEPT
# Example firewall rule (Windows): New-NetFirewallRule -DisplayName 'Restrict Epikur' -Direction Inbound -LocalPort [EPIKUR_PORT] -RemoteAddress [TRUSTED_NETWORK] -Action Allow
Password Policy Enforcement
allImplement account lockout policies and monitor for failed login attempts to detect exploitation attempts.
# Configure account lockout (example for Linux PAM): auth required pam_tally2.so deny=5 unlock_time=900
# Configure account lockout (Windows): net accounts /lockoutthreshold:5 /lockoutduration:30 /lockoutwindow:30
🧯 If You Can't Patch
- Immediately change all user passwords and enforce strong password policies
- Implement network segmentation and restrict Epikur server access to only necessary users/systems
🔍 How to Verify
Check if Vulnerable:
Attempt to authenticate to Epikur using the password '3p1kursupport' with any username. If authentication succeeds, the system is vulnerable.Check Version:
Check Epikur web interface or configuration files for version information. Consult vendor documentation for specific version check commands.Verify Fix Applied:
After patching, attempt authentication with '3p1kursupport' password. Authentication should fail. Also verify the server version is 20.1.1 or later.📡 Detection & Monitoring
Log Indicators:
- Successful logins with unusual usernames
- Multiple failed login attempts followed by success with different usernames
- Logins occurring from unexpected IP addresses or locations
Network Indicators:
- Authentication requests containing the password '3p1kursupport' in plaintext or MD5 hash
- Unusual authentication patterns or timing
SIEM Query:
source="epikur_logs" AND (event_type="authentication_success" AND (username="*" AND password_hash="md5_of_3p1kursupport")) OR (event_type="authentication_failure" AND password="3p1kursupport")