Socket Connection Audit

TL;DR

This guide shows you how to check an existing socket connection for security and performance issues. We’ll cover finding the process ID (PID) using the socket, checking open ports, identifying the remote address, and basic data inspection.

Checking Existing Socket Connections

1. Find the Process ID (PID) Using the Socket
   • First, you need to know the port number your socket is using. Let’s say it’s port 8080.
   • Use netstat or ss to find the PID associated with that port.

     netstat -tulnp | grep :8080

     ss -tulnp | grep :8080

   • The output will show you a line containing information about the socket, including the PID in the last column. For example:

     tcp        0      0 0.0.0.0:8080            0.0.0.0:*               LISTEN      1234/my_process

     In this case, the PID is 1234.

2. Check Open Ports
   • Confirm that only expected processes are listening on the port.

     netstat -tulnp

     ss -tulnp

   • Look for any unexpected or unknown processes.
3. Identify the Remote Address
   • Once you have the PID, use netstat or ss again to see the remote address connected to the socket.

     netstat -tulnp | grep 

     ss -tulnp | grep 

   • The output will show you the remote IP address and port number. For example:

     tcp        0      0 127.0.0.1:8080            192.168.1.100:54321         ESTABLISHED 1234/my_process

     Here, the remote address is 192.168.1.100 on port 54321.

4. Basic Data Inspection (Use with Caution!)
   • You can use tools like tcpdump or Wireshark to capture and inspect the data flowing through the socket.

     sudo tcpdump -i any port 8080

   • Warning: Capturing network traffic can expose sensitive information. Only do this in a controlled environment and with appropriate permissions. Be mindful of privacy regulations.
5. Check Socket Options (Advanced)
   • Use getsockopt in Python to retrieve socket options like SO_REUSEADDR, TCP_NODELAY.

     import socket
     
     s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
     s.connect(('127.0.0.1', 8080))
     reuseaddr = s.getsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR)
     nodelay = s.getsockopt(socket.IPPROTO_TCP, socket.TCP_NODELAY)
     print(f'SO_REUSEADDR: {reuseaddr}')
     print(f'TCP_NODELAY: {noddelay}')

   • Review these options to ensure they align with your security and performance requirements.

cyber security Considerations

• Firewall Rules: Ensure appropriate firewall rules are in place to restrict access to the socket port.
• Input Validation: Validate all data received through the socket to prevent injection attacks.
• Encryption: Use encryption (e.g., TLS/SSL) to protect sensitive data transmitted over the socket.