CVE-2020-7839
📋 TL;DR
CVE-2020-7839 is a command injection vulnerability in MaEPSBroker versions 2.5.0.31 and earlier. Attackers can execute arbitrary commands on affected systems by injecting malicious input into the brokerCommand parameter. Organizations using vulnerable MaEPSBroker software are affected.
💻 Affected Systems
- MaEPSBroker
📦 What is this software?
Maepsbroker by Markany
⚠️ Risk & Real-World Impact
Worst Case
Full system compromise allowing attackers to execute arbitrary commands with system privileges, potentially leading to data theft, ransomware deployment, or complete system takeover.
Likely Case
Remote code execution leading to unauthorized access, data exfiltration, or installation of backdoors on affected systems.
If Mitigated
Limited impact with proper input validation and network segmentation preventing exploitation.
🎯 Exploit Status
Command injection vulnerabilities typically have low exploitation complexity when details are known.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 2.5.0.32 or later
Vendor Advisory: https://www.markany.com/
Restart Required: Yes
Instructions:
1. Download the latest version from MarkAny's official website. 2. Backup current configuration. 3. Install the update. 4. Restart the MaEPSBroker service. 5. Verify the update was successful.
🔧 Temporary Workarounds
Network Segmentation
allRestrict network access to MaEPSBroker to only trusted sources
Use firewall rules to block external access to MaEPSBroker ports
Input Validation
allImplement additional input validation for brokerCommand parameter
Configure application-level filtering for command parameters
🧯 If You Can't Patch
- Implement strict network segmentation to isolate vulnerable systems
- Deploy web application firewall (WAF) with command injection rules
🔍 How to Verify
Check if Vulnerable:
Check MaEPSBroker version in application settings or installation directoryCheck Version:
Check application properties or installation manifest for version informationVerify Fix Applied:
Verify version is 2.5.0.32 or later and test brokerCommand parameter with safe test inputs📡 Detection & Monitoring
Log Indicators:
- Unusual command execution patterns in MaEPSBroker logs
- Suspicious process creation from MaEPSBroker
Network Indicators:
- Unexpected outbound connections from MaEPSBroker host
- Anomalous traffic to/from MaEPSBroker ports
SIEM Query:
Process creation where parent process contains 'MaEPSBroker' AND command line contains suspicious patterns like 'cmd.exe', 'powershell', or shell metacharacters