The Custom Button Installer dialog in Google Toolbar 4 and 5 beta presents certain domain names in the (1) "Downloaded from" and (2) "Privacy considerations" sections without verifying domain names, which makes it easier for remote attackers to spoof domain names and trick users into installing malicious button XML files, as demonstrated by presenting www.google.com when the button was downloaded from an arbitrary site through an open redirector on www.google.com.