Last month, 47 percent of all malware programs were Trojans, up from 30 in September, Trend Micro's latest virus roundup showed. Backdoor programs with Trojans made up for nearly 65 percent of malware detected.
Trojans and backdoor programs are major vectors for data theft, showing that these malware writers are out for profit, according to the vendor.
Trend Micro also found that the total number of malicious programs detected in October was 1,817, up 22 percent from September. The Netsky-P worm was the most prevalent malware last month, with 192,958 reported infections.