Protecting Windows Environment Using PowerShell #2: Using PowerShell to Secure Local User Accounts

Local user accounts are an essential component of any Windows system, but they can also be a source of security vulnerabilities if not managed properly. In order to maintain the security of a Windows environment, it is important to ensure that local user accounts are configured correctly and that sensitive information is protected. PowerShell provides a powerful set of tools for automating the process of securing local user accounts and can be used to implement security measures in a consistent and efficient manner.

One of the first steps in securing local user accounts is to enforce the use of strong passwords. The following script can be used to enforce password complexity and password expiration policies:

$passwordPolicy = (Get-CimInstance -ClassName Win32_PasswordPolicy)

$passwordPolicy.MinimumPasswordLength = 12
$passwordPolicy.PasswordComplexity = $True
$passwordPolicy.PasswordHistoryLength = 24
$passwordPolicy.MaxPasswordAge = (30).Days

Set-CimInstance -InputObject $passwordPolicy

In this example, the script uses the Get-CimInstance cmdlet to retrieve the current password policy and assign it to the $passwordPolicy variable. The script then sets the minimum password length to 12 characters, sets the password complexity requirement to True, sets the password history length to 24, and sets the maximum password age to 30 days. The script then uses the Set-CimInstance cmdlet to update the password policy.

Another important step in securing local user accounts is to prevent the use of easily guessable passwords. The following script can be used to check for easily guessable passwords and to change them if necessary:

$users = Get-LocalUser

foreach ($user in $users) {
    $password = ConvertTo-SecureString $user.Name -AsPlainText -Force
    $user.SetPassword($password)
}

In this example, the script uses the Get-LocalUser cmdlet to retrieve a list of all local users and assigns the results to the $users variable. The script then uses a for each loop to iterate through the list of users and uses the SetPassword method to set each user’s password to the same value as their username. This effectively prevents the use of easily guessable passwords.

Another important aspect of securing local user accounts is to limit the number of users who have administrative privileges on the system. The following script can be used to add a user to the local administrators group:

$username = "user1"
$group = [ADSI]"WinNT://$env:COMPUTERNAME/Administrators,group"
$user = [ADSI]"WinNT://$username,user"
$group.Add($user.Path)

In this example, the script uses the [ADSI] class to add the user specified in the $username variable to the local administrators group.

Finally, it is important to regularly review the local user accounts on a system in order to detect any unauthorized or suspicious activity. The following script can be used to create a report of all local user accounts and their properties:

$users = Get-LocalUser

$report = @()
foreach ($user in $users) {
    $properties = [ordered]@{
        "Username" = $user.Name
        "Full Name" = $user.FullName
        "Description" = $user.Description
        "Enabled" = $user.Enabled
    }
$report += New-Object -TypeName PSObject -Property $properties
}

$report | Export-Csv -Path "LocalUserAccounts.csv" -NoTypeInformation

In this example, the script uses the Get-LocalUser cmdlet to retrieve a list of all local users and assigns the results to the $users variable. The script then uses a for each loop to iterate through the list of users and creates an ordered hash table of user properties, including the username, full name, description, and enabled status. The script then adds each user’s information to the $report array, and finally uses the Export-Csv cmdlet to save the report to a CSV file.

In conclusion, using PowerShell to secure local user accounts is a powerful and effective way to maintain the security of a Windows environment. By enforcing password policies, preventing the use of easily guessable passwords, limiting administrative privileges, and regularly reviewing user accounts, you can ensure that your local user accounts are secure and protected against potential security threats.