CVE-2020-28870
📋 TL;DR
CVE-2020-28870 is a critical remote code execution vulnerability in InoERP 0.7.2 that allows unauthenticated attackers to execute arbitrary code on the server due to insufficient input validation in the /modules/sys/form_personalization/json_fp.php endpoint. This affects all organizations running vulnerable InoERP installations without proper input validation controls.
💻 Affected Systems
- InoERP
📦 What is this software?
Inoerp by Inoideas
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise allowing attackers to install malware, steal sensitive data, pivot to other systems, or deploy ransomware across the network.
Likely Case
Attackers gain shell access to the server, install backdoors, exfiltrate database contents, and potentially compromise the entire ERP system and connected infrastructure.
If Mitigated
Attack attempts are blocked at the web application firewall level, with failed exploitation attempts logged for investigation.
🎯 Exploit Status
Public exploit code is available on Exploit-DB (48946), making this easily weaponizable by attackers with minimal technical skill.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Versions after 0.7.2
Vendor Advisory: https://github.com/inoerp/inoerp
Restart Required: No
Instructions:
1. Upgrade InoERP to the latest version. 2. If upgrading is not possible, apply input validation to the json_fp.php endpoint. 3. Remove or restrict access to the vulnerable endpoint if not needed.
🔧 Temporary Workarounds
Block vulnerable endpoint
allRestrict access to the vulnerable PHP file using web server configuration or firewall rules
# Apache: RewriteRule ^/modules/sys/form_personalization/json_fp\.php$ - [F,L]
# Nginx: location ~ /modules/sys/form_personalization/json_fp\.php$ { deny all; }
Implement WAF rules
allAdd web application firewall rules to block malicious requests to the vulnerable endpoint
# ModSecurity rule: SecRule REQUEST_URI "@rx /modules/sys/form_personalization/json_fp\.php" "id:1001,phase:1,deny,status:403"
🧯 If You Can't Patch
- Implement strict network segmentation to isolate the InoERP server from critical systems
- Deploy a web application firewall with specific rules to block exploitation attempts and monitor for suspicious activity
🔍 How to Verify
Check if Vulnerable:
Check if /modules/sys/form_personalization/json_fp.php exists and is accessible without authentication. Test with a benign payload to see if input validation is missing.Check Version:
Check the InoERP version in the application interface or configuration files. For command line: grep -r "version" /path/to/inoerp/ | grep -i "0.7.2"Verify Fix Applied:
Attempt to access the vulnerable endpoint with test payloads and verify they are rejected. Check that input validation has been implemented in the PHP code.📡 Detection & Monitoring
Log Indicators:
- Unusual POST requests to /modules/sys/form_personalization/json_fp.php
- PHP execution errors or warnings in web server logs
- Suspicious system commands executed from web process
Network Indicators:
- Unusual outbound connections from the InoERP server
- Traffic patterns indicating data exfiltration
- Multiple failed exploitation attempts to the vulnerable endpoint
SIEM Query:
source="web_server_logs" AND (uri="/modules/sys/form_personalization/json_fp.php" OR (uri="/modules/sys/form_personalization/json_fp.php" AND (method="POST" OR params CONTAINS "system" OR params CONTAINS "exec")))