CVE-2025-27451
📋 TL;DR
This vulnerability allows attackers to enumerate valid usernames by observing different error messages for incorrect passwords versus non-existent usernames during failed login attempts. This affects any application or system that implements differential error messaging for authentication failures. Attackers can use this information to target valid accounts for further attacks.
💻 Affected Systems
- SICK industrial control systems and related software
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Attackers successfully enumerate all valid usernames, then use credential stuffing or brute force attacks to compromise accounts, potentially gaining unauthorized access to sensitive systems or data.
Likely Case
Attackers identify valid usernames and use them for targeted phishing, social engineering, or credential stuffing attacks against those specific accounts.
If Mitigated
Attackers cannot reliably determine valid usernames, forcing them to use less efficient attack methods that are more easily detected and blocked.
🎯 Exploit Status
Exploitation requires only basic scripting or manual testing to observe error message differences.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Not specified
Vendor Advisory: https://sick.com/psirt
Restart Required: No
Instructions:
1. Check vendor advisory for specific patch information. 2. Apply vendor-recommended updates. 3. Test authentication behavior after patching.
🔧 Temporary Workarounds
Standardize Error Messages
allModify authentication system to return identical generic error messages for all failed login attempts, regardless of whether username or password is incorrect.
Implement Rate Limiting
allAdd rate limiting on login attempts to prevent automated username enumeration.
🧯 If You Can't Patch
- Implement web application firewall (WAF) rules to detect and block username enumeration patterns
- Add CAPTCHA or other challenge-response mechanisms after failed login attempts
🔍 How to Verify
Check if Vulnerable:
Attempt login with non-existent username and observe error message, then attempt login with valid username but wrong password and compare error messages.Check Version:
Check system documentation or vendor-specific version commandsVerify Fix Applied:
Test that both invalid username and invalid password scenarios return identical generic error messages.📡 Detection & Monitoring
Log Indicators:
- Multiple failed login attempts with different usernames
- Pattern of failed logins followed by successful login from same IP
Network Indicators:
- Unusual volume of authentication requests
- Requests from tools like Burp Suite, Hydra, or custom scripts
SIEM Query:
source="auth.log" | stats count by src_ip, username | where count > threshold🔗 References
- https://sick.com/psirt
- https://sick.com/psirt
- https://www.cisa.gov/resources-tools/resources/ics-recommended-practices
- https://www.endress.com
- https://www.first.org/cvss/calculator/3.1
- https://www.sick.com/.well-known/csaf/white/2025/sca-2025-0008.json
- https://www.sick.com/.well-known/csaf/white/2025/sca-2025-0008.pdf
