CVE-2020-28045
📋 TL;DR
This CVE describes a signature bypass vulnerability in ProlinOS where shared libraries aren't verified for signatures, unlike applications and system binaries. An attacker can execute arbitrary code by compiling malicious code as a shared object and loading it via LD_PRELOAD. This affects ProlinOS point-of-sale systems through version 2.4.161.8859R.
💻 Affected Systems
- ProlinOS
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Full system compromise allowing execution of arbitrary code with kernel-level privileges, potentially leading to data theft, system manipulation, or deployment of persistent malware.
Likely Case
Local privilege escalation or execution of unauthorized applications by users with local access to the system.
If Mitigated
Limited impact if proper access controls prevent local user access and LD_PRELOAD usage is restricted.
🎯 Exploit Status
Exploitation requires local access to the system. The git repository contains proof-of-concept code demonstrating the vulnerability.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: Not provided in references
Restart Required: No
Instructions:
Check with ProlinOS vendor for security updates. If available, apply the patch following vendor instructions.
🔧 Temporary Workarounds
Restrict LD_PRELOAD usage
linuxPrevent users from setting LD_PRELOAD environment variable to block the exploitation vector.
Set appropriate permissions on /etc/ld.so.preload and restrict user environment variables
Implement strict access controls
allLimit local access to ProlinOS systems to authorized personnel only.
🧯 If You Can't Patch
- Isolate affected systems from critical networks and implement network segmentation
- Monitor for unusual process execution and LD_PRELOAD usage in system logs
🔍 How to Verify
Check if Vulnerable:
Check ProlinOS version: if version is 2.4.161.8859R or earlier, system is vulnerable. Test by attempting to load an unsigned shared library via LD_PRELOAD.Check Version:
Check system documentation or vendor-specific commands for ProlinOS versionVerify Fix Applied:
Verify that unsigned shared libraries can no longer be loaded via LD_PRELOAD after applying vendor patches or workarounds.📡 Detection & Monitoring
Log Indicators:
- Unusual process execution, LD_PRELOAD environment variable usage, execution of unsigned binaries
Network Indicators:
- Unusual outbound connections from ProlinOS systems
SIEM Query:
Process execution where command_line contains 'LD_PRELOAD' OR parent_process contains suspicious library loading