- Patch VPN gateways quickly: they are a top initial access target.
- Use certificates or MFA rather than shared secrets.
- Investigate unexpected tunnels and proxies: they are also attacker tools.
Port 4187: Cascade Proxy
Port 4187 is assigned by IANA to csc_proxy (Cascade Proxy), csc-proxy (Cascade Proxy IANA assigned this well-formed service name as a replacement for "csc_proxy".).
4187
How csc_proxy works
VPN, tunnels & proxiesTraffic is wrapped in a tunnel between the two ends, so the network in between only sees the tunnel.
- Transport
- TCP
- Exposure risk
- not rated depends on the program listening
- Encryption
- Unknownnot stated by the registry
- IANA status
- Assigned2 registered services
- Range
- Registered (1024-49151)
- Category
- VPN, tunnels & proxies
Is port 4187 dangerous?
We have no specific security note for port 4187. Its risk depends on the program actually listening on it. General advice for vpn, tunnels & proxies services:
IANA registry entries for port 4187
| Service | Port | Transport | Description | Reference | Updated |
|---|---|---|---|---|---|
| csc_proxy | 4187 | TCP | Cascade Proxy | - | 2008-09-11 |
| csc-proxy | 4187 | TCP | Cascade Proxy IANA assigned this well-formed service name as a replacement for "csc_proxy". | - | 2008-09-11 |
| - | 4187 | - | Reserved | - | - |
// source: IANA service name and port number registry
Which program uses port 4187, and is it reachable?
Linux
sudo ss -ltnup 'sport = :4187' # process listening on 4187
sudo lsof -nP -i :4187macOS
sudo lsof -nP -i :4187
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 4187 -State Listen | Select LocalAddress, OwningProcess Get-NetUDPEndpoint -LocalPort 4187 netstat -ano | findstr :4187
From another machine
nmap -p 4187 -sV <host> nc -zv <host> 4187
Block it in the firewall
sudo ufw deny 4187/tcp # Linux (ufw) New-NetFirewallRule -DisplayName "Block 4187" -Direction Inbound -LocalPort 4187 -Protocol TCP -Action Block # Windows
What is port 4187 used for?
Port 4187 is assigned by IANA to csc_proxy (Cascade Proxy), csc-proxy (Cascade Proxy IANA assigned this well-formed service name as a replacement for "csc_proxy".).
Is port 4187 TCP or UDP?
Port 4187 is registered for TCP.
Is it safe to open port 4187?
It depends on the program that listens on it. Open it only for a service you know and only to the networks that need it. Patch VPN gateways quickly: they are a top initial access target.
How do I check if port 4187 is open?
On Linux run "ss -ltnup 'sport = :4187'", on macOS "lsof -nP -i :4187", and on Windows "netstat -ano | findstr :4187" to see the local process. From another machine, "nmap -p 4187 <host>" shows whether it is reachable.