CVE-2022-28005
📋 TL;DR
This vulnerability in 3CX Phone System Management Console allows unauthenticated attackers to read arbitrary files via directory traversal, leading to credential disclosure. With stolen credentials, attackers can upload malicious files to overwrite system binaries, achieving remote code execution with SYSTEM privileges on Windows. All systems running affected versions with internet-facing management consoles are at risk.
💻 Affected Systems
- 3CX Phone System Management Console
📦 What is this software?
3cx by 3cx
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise with SYSTEM privileges, enabling data theft, ransomware deployment, and persistent backdoor installation.
Likely Case
Credential theft leading to unauthorized access, data exfiltration, and potential lateral movement within the network.
If Mitigated
Limited to credential exposure without ability to execute code if proper network segmentation and access controls are implemented.
🎯 Exploit Status
Exploitation chain involves two steps: unauthenticated file read followed by authenticated file upload. Public exploit code and detailed analysis available.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 18 Update 3 FINAL or later
Vendor Advisory: https://www.3cx.com/blog/releases/v18-update-3-final/
Restart Required: Yes
Instructions:
1. Backup current configuration. 2. Download and install version 18 Update 3 FINAL or later from 3CX website. 3. Restart the 3CX services. 4. Verify installation and test functionality.
🔧 Temporary Workarounds
Network Segmentation
allRestrict access to 3CX management console to trusted internal networks only
Web Server Configuration
allBlock access to /Electron/download path and implement proper input validation
🧯 If You Can't Patch
- Immediately isolate the 3CX server from internet access
- Implement strict network access controls and monitor for suspicious file access patterns
🔍 How to Verify
Check if Vulnerable:
Check 3CX version in Management Console dashboard. If version is below 18 Update 3 FINAL, system is vulnerable.Check Version:
Check version in 3CX Management Console interface or via web interfaceVerify Fix Applied:
Verify version shows 18 Update 3 FINAL or higher in Management Console. Test that /Electron/download path no longer allows directory traversal.📡 Detection & Monitoring
Log Indicators:
- Unusual file access patterns to /Electron/download
- Multiple failed authentication attempts followed by successful login
- Unauthorized file uploads to 3CX directories
Network Indicators:
- HTTP requests with directory traversal patterns (../, ..\) to /Electron/download
- Unexpected outbound connections from 3CX server
SIEM Query:
source="3cx" AND (url="*/Electron/download*" AND (url="*..*" OR url="*\\*")) OR (event="File Upload" AND process="3CX*")🔗 References
- https://medium.com/%40frycos/pwning-3cx-phone-management-backends-from-the-internet-d0096339dd88
- https://www.3cx.com/blog/change-log/phone-system-change-log/
- https://www.3cx.com/blog/releases/v18-security-hotfix/
- https://www.3cx.com/blog/releases/v18-update-3-final/
- https://medium.com/%40frycos/pwning-3cx-phone-management-backends-from-the-internet-d0096339dd88
- https://www.3cx.com/blog/change-log/phone-system-change-log/
- https://www.3cx.com/blog/releases/v18-security-hotfix/
- https://www.3cx.com/blog/releases/v18-update-3-final/
