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If you've gained access to a Windows domain, how would you go about determining the types of Windows computers on the rest of the network? You could run a port scan with Nmap or the Metasploit db_nmap command, but port scans garner a lot of attention. Instead we can take advantage of a very common Windows service - SMB. Server Message Block (SMB) operates on TCP:445, and runs on all modern versions of Windows, including Windows Server.

It allows computers to share files and printers, and Linux / UNIX platforms can run a compatible service called SAMBA. Fortunately for us it also tells a lot about the system that's running it.

We'll use the auxiliary/scanner/smb/smb_version module to probe hosts we've discovered so far for their SMB versions, which are listed below:

• v1.0 Windows XP, Server 2003 (Deprecated)
• v2.0: Windows Vista
• v2.1: Windows 7, Server 2008 R2
• v3.0: Windows 8, Server 2012
• v3.0.2: Windows 8.1, Server 2012 R2
• v3.1.1: Windows 10, Server 2016

We can get the SMB version without authenticating to the remote computer, SMB traffic on a local network isn't unusual at all, and we only need to probe one port to get what we need.

use auxiliary/scanner/smb/smb_version

I already have a few hosts listed when we run the hosts command, found by running a ping sweep, but I don't have much information on them except for the host I have a Meterpreter shell on:

I'll use the hosts -R command to take all the IPs listed under hosts and set them as RHOSTS:

hosts -R

We don't need to set any other options, though if we had valid domain credentials we could set the SMBUser, SMBPass, and SMBDomain options.

Run the SMB version scanner:

run

The scan only takes a few moments, and we can lists our hosts again:

The SMB version scan found the only other Windows machine on this network - a Windows 10 Pro computer. We can further target our exploits and social engineering activities with the new information.