TypeError in smb.py

[shaaati]

During a recent pentest I ran into an issue with the following code line:

https://github.com/SecureAuthCorp/impacket/blob/3c6713e309cae871d685fa443d3e21b7026a2155/impacket/smb.py#L3497

A crackmapexec run across a network segment crashed with the error message "TypeError: argument should be integer or bytes-like object, not 'str'".
It seems that get_server_lanman returns a bytes object. I worked around this crash by modifying the two arguments to the find function to bytes objects as well (b'Windows 2000'' and b'Samba').
Due to lack of code knowledge, I do not know if this is the correct fix and therefore did not directly propose a pull request.

Edit: The issue seems to be more complex. The same code line now crashed on another network segment with the error "TypeError: must be str, not bytes". Apparently, get_server_lanman can return both bytes and str.