An Instant Messenger Trojan is usually a standalone program that
affects a certain Instant Messenger (IM) client. There are a few
widely used instant messenger networks - ICQ, MSN, Yahoo!, AOL
and a few others. All these networks have specific clients that
are available to all subscribers. Some instant messenger clients,
for example Trillian, can connect to multiple IM networks.
Instant Messenger trojans are usually standalone programs that
are sent by hackers to their potential victims in e-mails or
instant messages. IM trojans are most frequently used to steal
user's IM account information. When such trojan is run, it tries
to locate an IM client's user information and to send it to a
hacker via e-mail or using the existing IM client. That way a
hacker gets all data he needs to connect to an IM network using
Most famous IM trojans: Ypager, Ikmet, Spy, ICQSteal.
Alexey Podrezov, July 14th, 2003;
Alexey Podrezov, November 17th, 2004;