Instant-messaging systems aren't the only way spammers can splash unwanted messages across PC users' screens. A utility in Windows XP and Windows 2000 called Windows Messenger Service was designed to let network administrators broadcast short messages to users to inform them that a server needs rebooting or a printer is out of toner.
But spammers soon discovered if they had the IP addresses of the intended recipients, they too could send short pop-up messages promoting their services, sending users to a Web site or even linking to an executable file that could launch a virus.
Microsoft says a fix is on the way. In Service Pack 2 of XP, slated for release before the end of June, Microsoft plans to include a utility that will "automatically disengage" Windows Messenger Service so that it can't be used, says Matt Pilla, senior product manager in the Windows Client Division. Microsoft also has posted on its Web site instructions for disabling Windows Messenger Service and configuring firewalls to protect from intruders.
Read more about security in Network World's Security section.