networkingprotocols

SMB

smbnetworkingprotocols
Plain English

SMB is the language Windows uses to share folders and printers on a network.

Technical Definition

SMB versions: SMB1 (insecure, exploited by WannaCry, disable it), SMB2, SMB3 (encryption, signing).

  • TCP 445 (older NetBIOS on 137 to 139).
  • Paths: \\server\share on Windows, smb://server/share elsewhere.
  • Never expose 445 to the internet.

Source: Microsoft SMB overview; CompTIA Network+ N10-009 Exam Objectives v4.0; CompTIA Security+ SY0-701 Exam Objectives v6.0

SMB in practice

$ sudo ss -tlnp | grep 445
$ sudo ufw allow from 192.168.1.0/24 to any app Samba
In the Wild

Network+ N10-009 objective 1.4 lists SMB on 445. Security+ SY0-701 objective 2.5 covers disabling ports and protocols, which includes SMB1.

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