CVE-2021-47703
📋 TL;DR
OpenBMCS 2.4 contains an unauthenticated Server-Side Request Forgery (SSRF) vulnerability that allows attackers to force the application to make HTTP requests to arbitrary internal or external systems. This enables firewall bypass, internal network enumeration, and session hijacking. Organizations running OpenBMCS 2.4 are affected.
💻 Affected Systems
- OpenBMCS
📦 What is this software?
Openbmcs by Openbmcs
⚠️ Risk & Real-World Impact
Worst Case
Complete internal network compromise through firewall bypass, credential theft via session hijacking, and lateral movement to critical systems.
Likely Case
Internal service enumeration, data exfiltration from internal systems, and potential session hijacking of OpenBMCS users.
If Mitigated
Limited to port scanning of internal services if proper network segmentation and input validation are implemented.
🎯 Exploit Status
Exploit code is publicly available and requires minimal technical skill to execute.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Not available
Vendor Advisory: https://www.openbmcs.com
Restart Required: No
Instructions:
No official patch available. Consider upgrading to a newer version if available or implementing workarounds.
🔧 Temporary Workarounds
Input Validation and Whitelisting
allImplement strict input validation on the 'ip' parameter to only allow expected values or implement URL whitelisting.
Modify phpquery.php to validate the 'ip' parameter against a whitelist of allowed hosts
Network Segmentation
allRestrict OpenBMCS server's outbound network access to only necessary internal services.
Configure firewall rules to block outbound HTTP/HTTPS from OpenBMCS server except to required services
🧯 If You Can't Patch
- Implement web application firewall (WAF) rules to block SSRF patterns
- Isolate OpenBMCS server in a restricted network segment with no access to sensitive internal systems
🔍 How to Verify
Check if Vulnerable:
Test by sending a request to phpquery.php with an external IP in the 'ip' parameter and checking if the server makes an outbound request.Check Version:
Check OpenBMCS version in application interface or configuration filesVerify Fix Applied:
Verify that requests with external IPs in the 'ip' parameter are rejected or properly validated.📡 Detection & Monitoring
Log Indicators:
- Unusual outbound HTTP requests from OpenBMCS server
- Requests to phpquery.php with external IP addresses
Network Indicators:
- HTTP traffic from OpenBMCS server to unexpected internal or external destinations
SIEM Query:
source_ip='OpenBMCS_Server_IP' AND (dest_port=80 OR dest_port=443) AND NOT dest_ip IN [allowed_ips]