Extracting Hashes and Domain Info From ntds.dit

Table of Contents

  • Using Impacket
  • Installing esedbexport
  • Extracting Domain Info with ntdsxtract
  • Summary

  • On internal pens, it's really common for me to get access to the Domain Controller and dump password hashes for all AD users. A lot of tools make this super easy, like smart_hashdump from Meterpreter, or secretsdump.py from Impacket.

    But occasionally, I end up with a hard copy of the NTDS.dit file and need to manually extract the information offline. This came up today and I decided to document the process. I'm not going to go into the details on how to obtain the files, but am going to assume I have everything I need already offline:

    • a copy of NTDS.dit (ntds.dit)
    • a copy of the SYSTEM registry hive (systemhive)
    $ file *
    ntds.dit:   Extensible storage engine DataBase, version 0x620, checksum 0xa50ff5a, page size 8192, DirtyShutdown, Windows version 6.1  
    systemhive: MS Windows registry file, NT/2000 or above  
    

    Using Impacket

    Update: @agsolino, the creator of Impacket just told me on Twitter that secretsdump.py has a LOCAL option that makes this incredibly easy! Can't believe I never realized that, but it makes sense that Impacket saves me time and trouble again ;)

    If you have the NTDS.dit file and the SYSTEM hive, simply use the secretsdump.py script to extract all the NT hashes:

    $ python secretsdump.py -ntds /root/ntds_cracking/ntds.dit -system /root/ntds_cracking/systemhive LOCAL
    

    It takes a little while, but it will spit out nicely formatted NTLM hashes for all the Domain users:

    Secretsdump

    This is definitely the easiest method. If you want to go through the exercise of exporting the tables and using ntdsxtract, the following steps can be taken too:

    Installing esedbexport

    The first step is to extract the tables from the NTDS.dit file using esedbexport, which is part of libesedb.

    To install, download the latest release of source code from the releases page:

    https://github.com/libyal/libesedb/releases

    I used the latest pre-release "libesedb-experimental-20170121".

    Download and extract the source code:

    $ wget https://github.com/libyal/libesedb/releases/download/20170121/libesedb-experimental-20170121.tar.gz
    
    $ tar xf libesedb-experimental-20170121.tar.gz
    
    $ cd libesedb-20170121/
    

    Now install the requirements for building:

    $ sudo apt-get install autoconf automake autopoint libtool pkg-config
    

    And configure, make and install libesedb:

    $ ./configure
    $ make
    $ sudo make install
    $ sudo ldconfig
    

    If all went well, you should have the export tool available at /usr/local/bin/esedbexport

    Dumping Tables

    Now that the tool is installed, use it to dump the tables from the ntds.dit file. This will create a new directory, called ntds.dit.export with the dumped tables:

    $ /usr/local/bin/esedbexport -m tables ntds.dit
    

    This step can take quite a while (20-30 minutes for me). At the end though, you should see it successfully extracted the tables:

    Extracted Tables

    The two important tables are the datatable and link_table, and both will be in ./ntds.dit.export/

    Extracting Domain Info with ntdsxtract

    Once the tables are extracted, there is a great set of Python tools that can be used to interact with the data and dump valuable data: ntdsxtract

    Clone the repository and the python scripts should be usable as-is. Or they can be installed system wide:

    $ git clone https://github.com/csababarta/ntdsxtract.git
    
    $ cd ntdsxtract/
    
    $ python setup.py build && python setup.py install
    

    Dumping User Info and Password Hashes

    The ntdsxtract tool dsusers.py can be used to dump user information and NT/LM password hashes from an extracted table. It requires three things:

    • datatable
    • link_table
    • system hive

    The syntax is:

    $ dsusers.py <datatable> <link_table> <output_dir> --syshive <systemhive> --passwordhashes <format options>
    

    The --pwdformat option spits out hash formats in either John format (john), oclHashcat (ocl) or OphCrack (ophc).

    It will also spit out all the User information to stdout, so it's helpful to tee the output to another file.

    To extract all NT and LM hashes in oclHashcat format and save them in "ntout" and "lmout" in the "output" directory:

    $ dsusers.py ntds.dit.export/datatable.3 ntds.dit.export/link_table.5 output --syshive systemhive --passwordhashes --pwdformat ocl --ntoutfile ntout --lmoutfile lmout |tee all_user_info.txt
    

    After it runs, the NT hashes will be output in oclHashcat ready format:

    [email protected]:~/ntds_cracking# head -n2 output/ntout  
    user1:BC62AC0F8EA9DD1AD703C8B4F0A968C4  
    user2:0E10081EDBCFB92DE6156F9046FF7881  
    

    Looking at the file we tee'd into, we can see other information about the users, such as SID, when the password was created, last logons, etc:

    User Info

    To crack the NT hashes with hashcat, use mode 1000:

    $ hashcat -m 1000 output/ntout --username /path/to/wordlist
    

    Bonus: Extracting Domain Computer Info

    Ntdsxtract also has a tool to extract domain computer information from the dumped tables. This can be useful for generating target lists offline.

    To use, supply it the datatable, output directory, and a csvfile to write to:

    $ dscomputers.py ntds.dit.export/datatable.3 computer_output --csvoutfile all_computers.csv
    

    It generates a nice CSV of all computers in the domain, with the following columns:

    $ head -n 1 computer_output/all_computers.csv
    "Record ID";"Computer name";"DNS name";"GUID";"SID";"OS name";"OS version";"When created";"When changed";"Bitlocker recovery name";"Bitlocker recovery GUID";"Bitlocker volume GUID";"Bitlocker when created";"Bitlocker when changed";"Bitlocker recovery password";"Dial-In Permission"
    

    Summary

    It's a lot easier and faster to just use secretsdump.py or other authenticated methods of domain reconaissance to dump user info, passwords hashes, etc.

    But if you end up with a copy of the NTDS.dit file and the SYSTEM hive and want to extract info offline, use this guide.

    Hope this helps someone out there!

    -ropnop

    ropnop

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