Malicious codes used for financial gain were the most active type of malware in July, according to PandaLabs . Trojans accounted for 26.7 per cent of all infections detected by ActiveScan that month, while Adware was responsible for a further 24.8 per cent. Together they accounted for the highest percentage of all infections in total.

Worms were the third most frequent malware type in July, at 8.3 per cent. But Backdoor Trojans (3.7 per cent), dialers (3.3 per cent), spyware (2.9 per cent) and bots (2.3 per cent) also represented a significant number of infections.

Trojan domination

"There are six Trojans in this month's list," said Luis Corrons, technical director of PandaLabs. "This is largely explained by the popularity that this type of malware has among cyber-crooks, in particular because after the first infection it can drop a lot more malware onto computers and steal confidential information, etc."

Of the most frequently detected specific malicious code, the Downloader.MDW Trojan topped the list. It works by downloading other types of malware onto the victim's computer. Malware is software designed to infiltrate or damage a computer system without the owner's informed consent.