Automated Password Reset/Change – PowerShell

I’ve had a need to reset password’s for accounts on an automated basis more so recently than before, so not knowing where to start, I took a look around the internet and found some pieces of code here and there that would start to fulfill my needs.

Basically, I was setting up an 802.11x authenticated wireless network, and had a requirement to automate the password change of a RADIUS authenticated Guest account that was sat in a locked down OU in the domain. This then needed to be random, secure and e-mailed to a public folder so that the employees could give their guests access to the guest network. The script just needs to be added to a scheduled task to run monthly. So I eventually ended up with this:

import-module activedirectory

[int] $len = 12
[string] $chars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"
$bytes = new-object "System.Byte[]" $len
$rng = new-object System.Security.Cryptography.RNGCryptoServiceProvider
$rng.GetBytes($bytes)
$result = ""
for( $i=0; $i -lt $len; $i++ )
{
$result += $chars[ $bytes[$i] % $chars.Length ] 
}
$result

$securestring = ConvertTo-securestring $result -asplaintext -force

get-aduser "GuestUserName" | set-adaccountpassword -newpassword $securestring

$month= get-date -format MMMM

###Sets the mail values
$FromAddress = "Wireless_Guest@some-domain.com"
$ToAddress = "public-folder@some-domain.com"
$MessageSubject = "New Wireless Guest Details for $month"
$MessageBody = "Username: GuestUserName          Password: $result"
$SendingServer = "my.mail-relay.com"

###Create the mail message and add the statistics text file as an attachment
$SMTPMessage = New-Object System.Net.Mail.MailMessage $FromAddress, $ToAddress, $MessageSubject, $MessageBody

###Send the message
$SMTPClient = New-Object System.Net.Mail.SMTPClient $SendingServer
$SMTPClient.Send($SMTPMessage)

In short:

Line 3: Specifies the number of characters in the generated password.
Line 4: The characters that can be used to generate the password.
Line 17: Reset’s the password on the AD account.
Line 19: Generates the month in long format to add to the e-mail Subject.
Line 22-26: Variables used for sending the e-mail.
Line 29: Generates the e-mail.
Lines 32 & 33: Sends the e-mail.

7 Replies to “Automated Password Reset/Change – PowerShell”

    1. Hi Tech,
      I’m afraid I’m unsure… are you running the script on the domain controller itself, or from a remote machine? Perhaps it’s asking you to authenticate with AD prior to changing the password…

      Regards,

      Dan

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