Computer users were more likely to be infected by Trojans than any other malware during the first quarter of 2007, according to research by Panda Software. 

"In 2006, spyware was the most widely-distributed malware. However, during the final months of last year, Trojans increased significantly," says Jeremy Matthews, CE of Panda Software SA. "This trend has been confirmed in the first three months of this year and Trojans are now the most damaging malware."
In addition to this, 74% of new malware variants that appeared during the first quarter of 2007 were Trojans – increase of 20% compared to the global data for 2006.
“Trojans have become a key weapon in the new cyber-crime strategy. The possibility of using them to steal all kinds of passwords, email addresses and other information makes them incredibly popular for cyber-crooks usually launch a lot of variants of a Trojan in a short period of time to infect as many computers as possible in a single attack.
"This has turned Trojans into the type of malware with the highest number of new variants month after month”, says Matthews.
Adware, responsible for 28% of infections, was the second most active category of malware in the first quarter.
“It is no surprise that Trojans and adware are the most widely-distributed categories, as they are both easy to profit from, which is now the main aim of malware creators. Both are designed to compile information about users, which cyber-crooks can rapidly convert into cash,” adds Matthews.
Other less relevant categories during the first quarter were worms (8%), dialers (5%) and spyware (3 %).
Despite the dominance of Trojans, the most active specific example of malware was the Sdbot.ftp worm. This is a script created by several members of the Sdbot family to download themselves onto computers. After this came Puce.E, a worm that uses P2P networks to spread.
Third on the list was Torpig.A, a Trojan that steals confidential user data, such as passwords stored on specific Windows services while fourth was the Brontok.H worm followed by Abwiz.A, a Trojan designed to steal passwords stored on the system.
Bagle.HX, a representative of the dangerous Bagle family was in sixth position.  This variant has rootkit features to hide its processes and it disables some security solutions’ functions. The aim in both cases is to make it more difficult to detect. PcClient.DU came seventh. This backdoor Trojan opens a port in the targeted computer so that a remote attacker can control it.
In eighth place was Netsky.P, a Trojan that exploits several vulnerabilities in Internet Explorer to spread. QQpass.JZ, a Trojan that steals confidential data was in the ninth place. Last on the list was KillAV.FG, a Trojan that ends several processes on the compromised computer, security tool processes among them.