Port 445 · SMB

Port 445 is SMB, TCP.

Server Message Block — Windows file and printer sharing, AD replication, WMI, and more. High-value lateral movement vector (EternalBlue, ransomware).

Palo Alto

Create the service object for this port, then allow the App-ID on it. Restricting the rule to the port's service object keeps the rule working on a non-default port and stops the App-ID matching on other ports. Replace the placeholders with your own rule name and zones.

set service tcp-445 protocol tcp port 445

set rulebase security rules <rule-name> from <from-zone> to <to-zone> source any destination any application smb service tcp-445 action allow
set rulebase security rules <rule-name> from <from-zone> to <to-zone> source any destination any application msrpc service tcp-445 action allow

Risk and exposure

Rated high risk. Services on this port are commonly targeted by attackers. Keep it off the internet, or put it behind a VPN or a strict source allow-list, and monitor access.

Check it

• Linux ss -tlnp | grep :445
• PowerShell Test-NetConnection <host> -Port 445
• nmap nmap -p 445 <host>

Related ports

• 139 NetBIOS Session
• 548 AFP
• 2049 NFS
• 515 LPD / LPR
• 631 IPP / CUPS
• 3702 WS-Discovery

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