CVE-2021-47664
📋 TL;DR
CVE-2021-47664 allows unauthenticated remote attackers to enumerate valid usernames due to improper authentication mechanisms. This affects systems with vulnerable authentication implementations, potentially exposing user accounts to attackers.
💻 Affected Systems
- Specific product information not provided in CVE description
⚠️ Manual Verification Required
This CVE does not have specific version information in our database, so automatic vulnerability detection cannot determine if your system is affected.
Why? The CVE database entry doesn't specify which versions are vulnerable (no version ranges provided by the vendor/NVD).
🔒 Custom verification scripts are available for registered users. Sign up free to download automated test scripts.
- Review the CVE details at NVD
- Check vendor security advisories for your specific version
- Test if the vulnerability is exploitable in your environment
- Consider updating to the latest version as a precaution
⚠️ Risk & Real-World Impact
Worst Case
Attackers can build targeted credential stuffing attacks using enumerated valid usernames, leading to account compromise and potential lateral movement.
Likely Case
Attackers enumerate valid usernames for reconnaissance, enabling more focused brute-force attacks against authentication systems.
If Mitigated
With proper rate limiting and authentication controls, impact is limited to reconnaissance without credential compromise.
🎯 Exploit Status
Username enumeration typically requires minimal technical skill and can be automated
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Not specified
Vendor Advisory: Not provided in references
Restart Required: No
Instructions:
Check vendor documentation for specific patching instructions as product details are not specified
🔧 Temporary Workarounds
Implement Rate Limiting
allLimit authentication attempts per IP address to prevent automated username enumeration
Use Consistent Response Times
allEnsure authentication endpoints return consistent response times regardless of username validity
🧯 If You Can't Patch
- Implement network-level controls to restrict access to authentication endpoints
- Deploy web application firewall rules to detect and block enumeration patterns
🔍 How to Verify
Check if Vulnerable:
Test authentication endpoints with valid and invalid usernames; if response differs (timing, error messages, etc.), system may be vulnerableCheck Version:
Check specific product documentation as affected products are not specifiedVerify Fix Applied:
Verify that authentication endpoints provide identical responses for valid and invalid usernames📡 Detection & Monitoring
Log Indicators:
- Multiple failed authentication attempts with different usernames from single IP
- Pattern of authentication requests with incremental usernames
Network Indicators:
- High volume of authentication requests to same endpoint
- Requests with systematically varied username parameters
SIEM Query:
source_ip=* AND (event_type="authentication_failure" OR event_type="login_attempt") | stats count by username, source_ip | where count > threshold