Port 445

Q: What is port 445?

Windows file and printer sharing (SMB) SMB (Server Message Block) on port 445 is the Windows protocol for shared network drives, printers, and inter-process communication. It is also used by Samba on Linux and macOS. It is one of the most dangerous ports to expose to the internet: the NSA's EternalBlue exploit targeting port 445 was weaponized by WannaCry in 2017, infecting hundreds of thousands of systems worldwide. This port must ALWAYS be blocked at the internet perimeter.

SMB

Windows file and printer sharing (SMB)

Port

445

Protocol

TCP

Service

SMB

Security

Dangerous

Full name: Server Message Block / Microsoft-DS

What is port 445?

SMB (Server Message Block) on port 445 is the Windows protocol for shared network drives, printers, and inter-process communication. It is also used by Samba on Linux and macOS. It is one of the most dangerous ports to expose to the internet: the NSA's EternalBlue exploit targeting port 445 was weaponized by WannaCry in 2017, infecting hundreds of thousands of systems worldwide. This port must ALWAYS be blocked at the internet perimeter.

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