Port 10247 — Unassigned, But Occupied

What This Port Is

Port 10247 is a registered port — in the 1024–49151 range that doesn't require system privileges to use. It has no official IANA service assignment. No RFC. No protocol standard. It's a blank line in the register, available to anyone who needs it.

Why It Appears in Real Systems

Windows Security Context

Port 10247 became visible because JuicyPotatoNG, a Windows local privilege escalation tool, chose it as the default listening port for a COM server.¹ The choice was deliberate: this port is generally available to non-privileged users on Windows systems. Administrators haven't blocked it. The OS doesn't reserve it. It sits there, unused and open.

When you run JuicyPotatoNG with the optional -l flag, you can specify a different port, but 10247 is the default because it reliably exists and listens without conflict.

Kubernetes Deployments

Port 10247 appears in nginx ingress controller configurations for pod-internal communication during configuration reloads.² Again, the choice reflects what's available—a port in the unassigned space where the system and applications won't collide.

Checking What's Listening

To see if anything is listening on port 10247 on your system:

Linux/macOS:

lsof -i :10247
netstat -tuln | grep 10247
ss -tuln | grep 10247

Windows:

netstat -ano | findstr :10247
Get-NetTCPConnection -LocalPort 10247 | Select-Object -Property *

Cross-platform (Python):

import socket
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
result = sock.connect_ex(('127.0.0.1', 10247))
print("Open" if result == 0 else "Closed")

Why Unassigned Ports Matter

The Internet's infrastructure runs on three tiers of ports:

• Well-known (0–1023) — HTTP, HTTPS, DNS, SSH. The famous ones. Reserved, protected.
• Registered (1024–49151) — Applications can claim them, but most sit empty. This is where 10247 lives.
• Dynamic (49152–65535) — Temporary, ephemeral, for outgoing connections.

Unassigned registered ports are the gap. They're not the Internet's front door (well-known) and not its throwaway scratchpad (dynamic). They're the empty rooms in the building where anyone with access can set up temporary infrastructure.

This is why 10247 got chosen—not because it's special, but because it's available. The absence of an official service is its actual function.

Why This Matters for Security

If port 10247 were assigned to a legitimate, widely-used service, listening on it would immediately signal compromise: "something's wrong here." But because it's unassigned, it sits quietly. A non-privileged user can listen. An administrator scanning for listening ports might miss it. Exploit code can hide behind it.

The openness of the registered port space—all those unassigned numbers—creates opportunity. For infrastructure. For exploitation. For whatever you can fit in the gap.