[!] Authentication error on x.x.x.x

[jjvargass]

the target server
139/tcp open netbios-ssn Samba smbd 3.X - 4.X (workgroup: WORKGROUP)
445/tcp open netbios-ssn Samba smbd 3.0.20-Debian (workgroup: WORKGROUP)
my version of smbclient
smbclient --version
Version 4.11.5-Debian
I solved problem smbclient with --option='client min protocol=NT1'

smbmap -H 10.10.10.3
[!] Authentication error on 10.10.10.3

there is a way to assign the option to smbmap

[ShawnDEvans]

I'll have to dig into Impacket a bit to see how to force SMB1 protocol. I'll keep you posted. Should be an easy change. Thanks for the feedback!

[b4ttler]

I too am having this issue for null sessions, I have pulled the latest Impacket.

[ShawnDEvans]

Thanks for the feedback. I made a super minor update. I'm not quite sure what is up with it. There's nothing particularly complicated about submitting a zero length string for a username and password. See if the tweak made a difference. Fingers crossed!

Edit:

I totally forgot about the SMBv1 support! I've done a bit of research on it, but I lack an SMBv1 server to test against. I'm a bit busy the next couple of weeks but I'll try to find some time to setup a lab and get this change pushed. I think it should be easy....but....well....famous last words. It seems like SMBv1 should be supported out of the gate with Impacket, but I'm going to try forcing the SMB dialect to see if that changes anything.