No caso do MSN Messenger da Microsoft, o código malicioso aproveitando a falha foi publicado na Internet: ele usa uma falha no componente "libpng" do MSN Messenger, utilizado para mostrar diferentes imagens do formato PNG. Enquanto isso, o AOL Instant Messenger foi pego esta semana pelo worm_Aimdes.A: o vírus envia uma cópia de si mesmo para todos os contatos on-line da lista de um usuário infectado, enviando uma mensagem para enganar as possíveis vítimas. O worm também pode se espalhar via e-mail.

IM viruses and worms have been grabbing headlines over the past few months; this week alone saw virus issues plague popular IM systems from both Microsoft and AOL.

In the Microsoft MSN Messenger case, malicious code that could be used to create an IM virus was published on the Web. The code attacks a hole in an MSN Messenger component called "libpng," which is used to display Portable Network Graphics files that are used to show smiley faces, buddy icons, and other graphics, according to the IDG News Service.

AOL's AIM, meanwhile, was hit this week with a virus dubbed Worm_Aimdes.A, according to IM security vendor Akonix Systems. The virus sends a copy of itself to all online contacts in an affected user's Buddy List, sending a message in an attempt to trick recipient into thinking the file was send from a trusted source. That worm can also spread over e-mail networks.

Fonte Info World