one of the most interesting developments in 2007 was the appearance of worms for instant messenger applications. Instant messenger applications have become very popular, but users rarely perceive them as potential infection vectors. Although IM-worms were detected prior to 2007, the start of the year brought a noticeable increase in this type of malware.
An analysis of the IM-worms detected so far this year provides some data on possible future trends.
As Table 1 shows, most new IM-worms target MSN Messenger, which is extremely popular in the United States, but almost never used in Russia. All the worms except for Atlex are written in Visual Basic.
These two facts taken together seem to indicate that IM-worms are at the initial stage of evolution. And the fact that the vast majority of the worms are written in Visual Basic demonstrates that most of the authors are fairly new to the virus writing scene and are relatively inexperienced programmers. VB is one of the easiest programming languages to master, but it's unsuitable for serious projects due to the large files and the relatively slow speed that results from this.