CVE-2025-40806
📋 TL;DR
Gridscale X Prepay versions before V4.2.1 have a user enumeration vulnerability where attackers can distinguish between valid and invalid users based on application responses. This allows unauthenticated remote attackers to identify valid user accounts, enabling targeted brute force attacks. All users of affected Gridscale X Prepay versions are impacted.
💻 Affected Systems
- Gridscale X Prepay
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Attackers enumerate all valid user accounts and successfully brute force credentials, gaining unauthorized access to the system and potentially compromising sensitive data or functionality.
Likely Case
Attackers identify some valid user accounts and attempt credential stuffing or brute force attacks, potentially gaining access to low-privilege accounts.
If Mitigated
Attackers can enumerate users but cannot successfully authenticate due to strong password policies, account lockouts, or other authentication controls.
🎯 Exploit Status
User enumeration typically requires minimal technical skill and can be automated with simple scripts.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: V4.2.1
Vendor Advisory: https://cert-portal.siemens.com/productcert/html/ssa-356310.html
Restart Required: Yes
Instructions:
1. Download Gridscale X Prepay V4.2.1 or later from Siemens. 2. Backup current installation and data. 3. Apply the update following Siemens installation procedures. 4. Restart the application/service. 5. Verify successful update.
🔧 Temporary Workarounds
Implement Web Application Firewall (WAF)
allConfigure WAF rules to detect and block user enumeration attempts by monitoring for patterns in authentication requests.
Rate Limiting
allImplement rate limiting on authentication endpoints to slow down enumeration attempts.
🧯 If You Can't Patch
- Implement strong password policies and account lockout mechanisms to mitigate brute force attacks
- Monitor authentication logs for enumeration patterns and block suspicious IP addresses
🔍 How to Verify
Check if Vulnerable:
Test authentication endpoints with valid and invalid usernames; if responses differ in timing, content, or error messages, the system is vulnerable.Check Version:
Check application version in admin interface or configuration filesVerify Fix Applied:
After patching, repeat user enumeration tests; responses should be identical for valid and invalid users.📡 Detection & Monitoring
Log Indicators:
- Multiple failed login attempts for different usernames from same source
- Pattern of authentication requests with varying usernames
Network Indicators:
- Unusual volume of authentication requests
- Requests to authentication endpoints from suspicious IPs
SIEM Query:
source_ip=* AND (event_type="authentication_failure" OR event_type="login_attempt") | stats count by username, source_ip | where count > threshold