CVE-2022-23944
📋 TL;DR
Apache ShenYu versions 2.4.0 and 2.4.1 have an authentication bypass vulnerability in the /plugin API endpoint. This allows unauthenticated attackers to access plugin functionality, potentially leading to unauthorized actions or data exposure. Organizations running these vulnerable versions are affected.
💻 Affected Systems
- Apache ShenYu
📦 What is this software?
Shenyu by Apache
Shenyu by Apache
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise through plugin exploitation, data exfiltration, or remote code execution via vulnerable plugins.
Likely Case
Unauthorized access to plugin functionality, potential data leakage, and privilege escalation depending on plugin capabilities.
If Mitigated
Limited impact if network segmentation restricts access or if plugins have additional security controls.
🎯 Exploit Status
Simple HTTP requests to /plugin endpoint bypass authentication. Public discussions and proof-of-concept details exist in security mailing lists.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Apache ShenYu 2.4.2 and later
Vendor Advisory: https://lists.apache.org/thread/dbrjnnlrf80dr0f92k5r2ysfvf1kr67y
Restart Required: Yes
Instructions:
1. Download Apache ShenYu 2.4.2 or later from official sources. 2. Stop the current ShenYu service. 3. Replace with patched version. 4. Restart the ShenYu service. 5. Verify authentication is required for /plugin API.
🔧 Temporary Workarounds
Network Access Control
linuxRestrict network access to ShenYu API endpoints using firewall rules or network segmentation.
iptables -A INPUT -p tcp --dport [shenyu-port] -s [trusted-ips] -j ACCEPT
iptables -A INPUT -p tcp --dport [shenyu-port] -j DROP
Reverse Proxy Authentication
allPlace ShenYu behind a reverse proxy that enforces authentication before forwarding to /plugin endpoint.
🧯 If You Can't Patch
- Implement strict network segmentation to isolate ShenYu from untrusted networks.
- Deploy a web application firewall (WAF) with rules to block unauthenticated /plugin API requests.
🔍 How to Verify
Check if Vulnerable:
Send HTTP GET request to http://[shenyu-host]:[port]/plugin without authentication. If it returns data (not 401/403), system is vulnerable.Check Version:
Check ShenYu startup logs or admin interface for version number, or examine application configuration files.Verify Fix Applied:
After patching, attempt same unauthenticated request to /plugin endpoint. Should receive 401 Unauthorized or 403 Forbidden.📡 Detection & Monitoring
Log Indicators:
- Unauthenticated requests to /plugin endpoint in access logs
- Increased plugin API usage from unauthenticated sources
Network Indicators:
- HTTP traffic to /plugin endpoint without authentication headers
- Unusual plugin-related network patterns
SIEM Query:
source="shenyu_access.log" AND uri="/plugin" AND (NOT auth_header=*)🔗 References
- http://www.openwall.com/lists/oss-security/2022/01/25/15
- http://www.openwall.com/lists/oss-security/2022/01/25/5
- http://www.openwall.com/lists/oss-security/2022/01/26/2
- https://lists.apache.org/thread/dbrjnnlrf80dr0f92k5r2ysfvf1kr67y
- http://www.openwall.com/lists/oss-security/2022/01/25/15
- http://www.openwall.com/lists/oss-security/2022/01/25/5
- http://www.openwall.com/lists/oss-security/2022/01/26/2
- https://lists.apache.org/thread/dbrjnnlrf80dr0f92k5r2ysfvf1kr67y
