The first known virus that spreads by MSN's Messenger Service application has been discovered.

W32/Hello, an Internet worm that affects Windows machines, arrives via MSN Messenger as a file called Hello.exe.

If a user clicks on the file, which is actually a Visual Basic 5 application, the worm creates a shortcut, with no name or icon, in the Windows Start-up folder. It will then attempt to send a copy of itself along with the message "i have a file for u. its real funny", to people on the contact list of an infected user's machine.

If MSN Messenger is not installed on the machine in the expected directory the worm will crash, displaying the message "Run-time Error '91'. Object variable or With block variable not set."

Jack Clark, European product manager at Network Associates, played down the risk of the worm, which he described as low risk because it is neither spreading rapidly nor capable of doing much damage. He said the importance of the Hello worm was as an early warning that users should be careful of instant messaging applications, which could become a vector for the spread of malicious code.

"The Hello worm highlights the fact that if a service becomes prolific, virus authors will target it," said Clark, who added that since corporate firewalls commonly block instant messenger the issue mainly affects consumers.

Antivirus vendors are in the process of updating their software to deal with the virus and, in most cases, the necessary protection is already in place. Users are also advised to apply the principles of safe computing and to be careful about which programs they allow to install themselves on their machines. ®

External links

Hello worm

Related stories

Gnutella users warned of Internet worm
Reports of death of email viruses greatly exaggerated?
Microsoft security fixes infected with FunLove virus
Rise in viruses within emails outpacing growth of email
Users haven't learned any lessons from the Love Bug