Instead of cracking hashes to find the clear password, you can relay those hashes to specific machines and potentially gain access.
For refreshing our memory about the different types of NTLMs and Relaying 101 and pass-the-hash attack i suggest you read these 2 awesome posts :
Now, this attack requires two things :
SMB signing must be disabled on the target
Relayed user credentials must be admin on the machine (we can't relay the hash to the same machine since MS08-068, and the user we're relaying must have admin rights on the target machine if we want code execution otherwise user access if there's an open-share for example)
In order to relay hashes, we must have valid targets. Valid targets are, as predescribed, machines with SMB Signing disabled. So to get a list of those valide targets we can use for example CrackMapExec
NOTE: By default, SMB signing is enabled on all DC servers
Now off to capture the hashes, but we first need to change a little configuration in the responder.conf file (/usr/share/responder/responder.conf)
[Responder Core]
; Servers to start
SQL = On
SMB = Off # Turn this off
Kerberos = On
FTP = On
POP = On
SMTP = On
IMAP = On
HTTP = Off # Turn this off
HTTPS = On
DNS = On
LDAP = On
Then again fire up responder :
python responder.py -I <interface> -rdwv
Now off to the relay, pop up a new shell and use ntlmrelayx.py to relay the intercepted hashes :
ntlmrelayx.py -tf Targets.txt -socks -smb2support
You should be seeing something cool appearing on your ntlmrelay window.
Now while that's cool, what can we do with the opened sessions ? if you tap socks you should see something like that :
