Add SMB_302 to possible SMB3 dialects

[NeffIsBack]

With commit 8f81720 impacket will automatically negotiate SMB 3.1.1 which enforces signing. Since in NetExec we would still use unsigned SMB connections (e.g. for signing enforcement enumeration, see Pennyw0rth/NetExec#1292) I would like to be able to specify the latest non-signing required SMB dialect which is SMB 3.0.2. However, currently this is simply missing in the options to create an SMB3 connection and therefore fails.

Keep in mind that 8f81720 might also has affected impacket scripts or the relay server, but haven't tested those specifically.

Before&After:

[NeffIsBack]

@anadrianmanrique, @gabrielg5, @alexisbalbachan since this is quite a critical bug for NetExec, it would be nice if one of you could check this out (sorry for the ping if you already saw this).

EDIT:
We have fixed the problem without explicitly specifying a preferred dialect, so this is merely a bug fix now, no need to rush anything.

[anadrianmanrique]

Hello, thanks for reporting the issue. Based on your report we've found a couple of additional potential issues in:

• impacket/impacket/smb3.py

  Line 658 in 00e25d4

  if (negResp['SecurityMode'] & SMB2_NEGOTIATE_SIGNING_REQUIRED) == SMB2_NEGOTIATE_SIGNING_REQUIRED or \

  where require signing it's activated as soon as 3.1.1 dialects it's detected.
• impacket/smbconnection.py : methods listSnapshots(), createMountPoint(), removeMountPoint() which are currently checking the version dialect range in a non-consistent way
• for ntlmrelay, impacket/examples/ntlmrelayx/clients/smbrelayclient.py:94 defaults to [SMB2_DIALECT_002, SMB2_DIALECT_21, SMB2_DIALECT_30]. Don't really know if SMB2_DIALECT_311 with signing disabled would work. It should probably be tested.

Given that you were able to solve the issue in your project, if you are ok, I will close this PR without margining it, and open a new one addressing the above mentioned issues.

Thanks!

[NeffIsBack]

Absolutely! If you have a better way of fixing it (and even make signing checking more reliable/straight forward in the process) feel free to close!