Empty Password

It is possible that accounts have an empty password if the useraccountcontrol attribute contains the value PASSWD_NOT_REQ.

Configuring

Prerequisite

Username Enumeration

Configuring

1. Open the "Active Directory Users and Computers" administration tool on DC02.

2. Click on "View" and enable "Avanced Features"

3. Open "Employees", right click the user steve and click on "Properties"

4. Open "Attribute Editor", search for "Useraccountcontrol" and click "Edit".

5. Set the value to 544 and cick "OK".

6. Click "Apply" and "OK".

7. Right click on Steve and select "Reset Password". Uncheck "User must change password at next logon" and make sure the Password fields are empty. Click on "OK"

Attacking

How it works

It is possible that accounts have an empty password if the useraccountcontrol attribute contains the value PASSWD_NOT_REQ.

Tools

• Crackmapexec

Executing the attack

1. Check if any on the users have a empty password by spraying an empty password for all the enumerated users against DC02.

crackmapexec smb 10.0.0.3 -u users.txt -p '' -d amsterdam.bank.local

Spraying an empty password counts as a invalid login. So it is advised to not do this while also passwordspraying as it might cause account lockouts.

2. The user Steve has an empty password and could be used for further enumeration.

Defending

Recommendations

• Periodically check for users with the PASSWD_NOT_REQ attribute and remove it.

Check for users with the attribute:

Get-ADUser -Filter {PasswordNotRequired -eq $true} | Select-Object samAccountName

Remove the attribute:

Set-ADAccountControl -PasswordNotRequired $false -Identity <USER>

Check for users with the attribute and remove the attribute:

Get-ADUser -Filter {PasswordNotRequired -eq $true} | Set-ADAccountControl -PasswordNotRequired $false

Detection

References

Find AD accounts using Password-Not-Required (blank password)Specops Software

GitHub - byt3bl33d3r/CrackMapExec: A swiss army knife for pentesting networksGitHub