Malicious Code Types by Volume

During the first half of 2007, Trojans made up 54 % of the volume of the top 50 malicious code reports, an increase over the 45 % reported in the final six months of 2006. While part of this increase can be attributed to the success of the Peacomm Trojan, there were also a wide variety of other Trojans present in the top 50 malicious code reports. As previously mentioned, Trojans are likely gaining prominence because they generate a low volume of traffic compared to network and mass-mailing worms.

Source: Symantec Internet Security Threat Report, Vol. XII