CVE-2021-45427
📋 TL;DR
CVE-2021-45427 allows unauthenticated attackers to delete arbitrary files on Emerson XWEB 300D EVO systems due to path traversal vulnerabilities and incorrect access controls. This affects industrial control systems running vulnerable versions, potentially disrupting critical operations.
💻 Affected Systems
- Emerson XWEB 300D EVO
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise through deletion of critical system files, configuration files, or application binaries leading to system crashes, data loss, and operational disruption in industrial environments.
Likely Case
Unauthenticated attackers deleting web application files, configuration files, or log files causing service disruption, loss of operational data, and potential denial of service.
If Mitigated
Limited impact with proper network segmentation, authentication requirements, and file permission controls preventing unauthorized access to critical systems.
🎯 Exploit Status
Exploitation requires only HTTP requests with path traversal sequences; no authentication needed.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Not specified in available references
Vendor Advisory: Not provided in references
Restart Required: No
Instructions:
Contact Emerson for updated firmware or security patches. Check Emerson's security advisories for official remediation guidance.
🔧 Temporary Workarounds
Network Segmentation
allIsolate Emerson XWEB systems from untrusted networks and internet access
Access Control Lists
allImplement strict firewall rules to limit access to Emerson XWEB systems only from authorized management stations
🧯 If You Can't Patch
- Implement network segmentation to isolate vulnerable systems from untrusted networks
- Deploy web application firewalls (WAF) with path traversal protection rules
🔍 How to Verify
Check if Vulnerable:
Check firmware version via device web interface or management console. If version is 3.0.7--3ee403, system is vulnerable.Check Version:
Check via device web interface or Emerson management tools; no universal CLI command available.Verify Fix Applied:
Verify firmware has been updated to a version beyond 3.0.7--3ee403. Test with controlled path traversal attempts (in safe environment).📡 Detection & Monitoring
Log Indicators:
- HTTP requests containing '../' sequences or attempts to access/delate files outside web root
- Unauthenticated file deletion attempts in web server logs
Network Indicators:
- HTTP DELETE or POST requests with path traversal sequences to Emerson XWEB systems
SIEM Query:
source="web_logs" AND (uri="*../*" OR method="DELETE") AND dest_ip="[XWEB_IP]"🔗 References
- https://drive.google.com/file/d/1IN7p9OKRgdszMVC1TKuZQDa4ySCPmQzO/view?usp=sharing
- https://drive.google.com/file/d/1RegGlCrtyQwW9DUirAbPDiIHKBWgsBea/view?usp=sharing
- https://drive.google.com/file/d/1iusYdheb62dom0DnvAzEiNR-e4EXSf2k/view?usp=sharing
- https://drive.google.com/file/d/1IN7p9OKRgdszMVC1TKuZQDa4ySCPmQzO/view?usp=sharing
- https://drive.google.com/file/d/1RegGlCrtyQwW9DUirAbPDiIHKBWgsBea/view?usp=sharing
- https://drive.google.com/file/d/1iusYdheb62dom0DnvAzEiNR-e4EXSf2k/view?usp=sharing
