Much easier than that. Installez le (depending on votre flavour of votre workstation OS) Remote Server Administration Tools so you get le AD DS tools. Don't forget to go into votre Windows Features in Control Panel to activez le correct toolsets.
Once you've done that, le suivant command will achieve votre desired result:
DSQUERY user "OU=myOU,OU=myUsers,DC=myDomain,DC=loc" -limit 0 | DSMOD user -pwd <insert new password here>
~ Replace "OU=myOU,OU=myUsers,DC=myDomain,DC=loc" avec le distinguishedName of le OU containing le users to be changed