Edit

SQL Server default login

By default the SA user is NOT enabled. Administrators might enable it during the installation and choose a weak password.

Configuring

  1. Login to WEB01 as the Administrator user with password Welcome01!.

2. Open "Microsoft SQL Server Management Studio"

3. Login with the Administrator user using Windows Authentication.

4. Expand the "Security" and "Logins" folders. Right click "sa" and select "Properties". Make sure "Enforce password policy" is unchecked and fill in the password sa twice.

Attacking

How it works

One of the default users (not enabled by default) for SQL Server is the SA user. Administrators might enable it during the installation and choose a weak password, such as the username.

Tools

Executing the attack

  1. Check if the MSSQL server on WEB01 can be contacted from our Kali machine:

2. Paste the following passwords in passwords.txt to spray with:

3. Run Crackmapexec to connect to the MSSQL service running on WEB01 and passwordspray the passwords till there is a succesfull login:

We got a succesfull login as the sa user with the password sa.

4. Run Crackmapexec again with the password sa and use the -q flag to try to execute the query select @@version to retrieve the MSSQL version.

5. Connect to the database using mssql-cli.

Check the executing commands page under SQL Server Attacks to learn to execute cmd commands:

Executing Commands

Defending

Recommendations

  • Make sure the password policy is enforced for all users on the SQL server.

  • Dont use the sa account, this account is well to known and attackers will attempt to brute-force it.

Detection

References

LogoGitHub - byt3bl33d3r/CrackMapExec: A swiss army knife for pentesting networksGitHub
Logomssql-cli - SQL ServerMicrosoftLearn
PreviousSMB Null-Session (To-Do)NextActive Directory Attacks

Last updated