Targeted e-mail attacks are most often directed at top company executives, as well as government officials responsible for foreign trade and defense, particularly those who deal with Asia, a Symantec report has found.
Released Friday, the antivirus company's MessageLabs Intelligence Report for the month listed the top five targeted roles in companies as: Director, senior official, vice president, manager and executive director.
Symantec also said individuals working with policies pertaining to Asian countries were targets.
Senders from China sent the most volume of infected e-mail, at 28.2 percent, while malware-laced messages originating from Romania and the United States registered 21.1 percent, and 13.8 percent, respectively. To derive these statistics, Symantec analyzed the IP addresses of the senders, and not Web servers.
The most dangerous file type attached to these e-mail messages was encrypted .rar, a compressed archive format. While .doc and .xls document files were more commonly found, nearly all the encrypted .rar attachments, or 96.8 percent, were found to be compromised.
Paul Wood, MessageLabs Intelligence senior analyst, pointed out in a company statement that .rar files were different from their unencrypted counterparts, which are rarely exploited and occur in 1.1 percent of e-mail messages.
Encrypted .rar files accounted for 0.32 percent of messages.
Hackers may be choosing these file types over .exe executables, which tend to cause suspicion when arriving as attachments, Wood said.
Spam increased in March
Overall, the global ratio of spam was 90.7 percent in March--a 1.5 percent increase over last month, noted Symantec. Singapore's spam rate of 88.3 percent was below the global average.
Virus activity dropped slightly, according to the report. Virus-infected e-mail messages made up 0.28 percent of messages in March, a drop of 0.05 from February, with e-mail pointing to malicious Web sites dropping 13.7 percent to hit 16.7 percent of messages.
Phishing dipped 0.02 percent to account for 0.19 percent of e-mail messages, but when judged against other e-mail threats bearing viruses, the proportion of phishing e-mail increased by 8.4 percent to form 64.6 percent of all e-mail threats.