How to Hack Databases: Cracking SQL Server Passwords & Owning the Server
Welcome back, my rookie hackers!
A short while back, I began a new series on database hacking. and now it's time to continue and extend your education in that field. As you know, the database contains all of the most valuable info for the hacker, including personally identifiable information, credit card numbers, intellectual property, etc. So, it's the ultimate goal of cybercrime and the APT hacker.
If you haven't read my guide on getting started in database hacking. this would be a good time to brush up on some basic concepts. In addition, I also did a tutorial on finding SQL Server databases. and I recommend reading both of those guides before continuing below.
In this tutorial, we'll look at how we can crack the password on the system admin (sa) account on the database, install a meterpreter payload through calling the stored procedure xp_cmdshell. and wreak havoc on their system.
Step 1: Start Metasploit
First, we need to start Metasploit. Once we have the metasploit command prompt, we need to define which module we want to use. In past Metasploit tutorials, we've always used exploits, but this one is a bit different. Instead, we will use a scanner among the auxiliary modules that enables us to brute force the sa password. Let's load up mssql_login :
- use scanner/mssql/mssql_login
As you can see, Metasploit responds by telling us we have successfully loaded this auxiliary module. Now let's take a look at the options
with this module.
Step 2: Set Your Options
In order to run this MS SQL login module, we will need:
- A password file,
- Set the RHOSTS, and
- Determine the number of THREADS we want to run.
BackTrack has a wordlist specially built for MS SQL password hacking with over 57,000 commonly used SQL passwords at /pentest/exploits/fasttrack/bin/wordlist.txt. In this case, our target is at 192.168.1.103, and we will set our THREADS to 20.
Step 3: Brute Force the Database Passwords
Now, we simply need to type exploit and it runs through password list until it finds the password for the sa account.
As you can see, after testing over 57,000 passwords (it takes a few minutes, so be patient), it found the password on our sa account of "NullByte". Success! Now we have full sysadmin privileges on the database that we can hopefully convert to full system sysadmin privileges.
Step 4: Grab the xp__cmdshell
Now that we have full sysadmin (sa) on the MS SQL database, we are going to leverage that to full system sysadmin privileges. MS SQL Server has a stored procedure named xp_cmdshell that enables the sa account to gain a system command shell with full system admin rights. If we can invoke that command shell, we may be able to load the payload of our choice on the system and own that system.
Metasploit has a exploit module named windows/mssql/mssqlpayload that attempts to do this. Let's load it.
- use windows/mssql/mssql_payload