Malicious software cases rose 22 percent in October, with Trojan horses accounting for nearly half, according to a newly released report by security company Trend Micro's TrendLabs.
Those results further validate a growing concern in the security industry that hackers are more interested in turning a profit than gaining fame. Trojan horses can be used to dupe computer users into running a bot program, which in turn can help launch denial of service attacks for financial gain.
"Trojans, at 47 percent of all malware (malicious software) discovered (in October), continue to comprise the bulk of discovered malware. This validates earlier statements that the motivation of malware authors is shifting from the traditional goal of claiming fame and notoriety to the pursuit of profit and monetary rewards," the report said.
During October, TrendLabs documented 1,817 cases of malicious software—a 22 percent rise over the previous month. Of that group, nearly half, 47 percent, were Trojan horses.
The report said the "usual suspects" appeared in its World Virus Tracking Center list of the 10 most widespread viruses, Trojans and so on, but the number of infections from malware on that list was down 20 percent from September.
One exception was the Netsky.P worm, which occupied the top spot in October. Netsky.P registered a 30 percent increase in infections over September.
"The major issue in Netsky's consistent prevalence is the fact that it rides on the seemingly irremediable human penchant for opening attachments in e-mail messages, even from unknown sources," the report said.
The concern over a rise in hackers using Trojan horses and viruses as a means to make money has been growing over the past 18 months.
Security experts suspect that last year's Sobig mass-mailing computer virus also fell into the moneymaking category. The virus would load software onto users' computers in order to provide a means for bulk e-mailers to use the zombie machines to send out unsolicited messages without detection.