Only 8,4% of e-mails that reach companies are legitimate – 89,88% of them are spam, while 1,11% are infected with malware.
This data was compiled after the analysis of 430-million email messages last year by TrustLayer Mail, a clean mail managed service from Panda Security.
Only January witnessed levels of spam below 80%. During the rest of the year, the amount of spam fluctuated, peaking in the second quarter at 94,27%.
"With respect to infected messages, the Netsky.P worm was the most frequently detected malicious code," says Jeremy Matthews, head of Panda's sub-Saharan operations. "This type of malware activates automatically when users view the infected message through the Microsoft Outlook preview pane. It does this by exploiting a vulnerability in Internet Explorer that allows automatic execution of email attachments.
"The fact that these two malicious codes often act in unison explains the high number of detections of both," Matthews adds. "Cybercrooks often launch several strains of malware with each exploit to increase the chances of infection, so even if users whose systems are up-to-date are immune to the exploit, they could still fall victim to infection by the worm if they run the attachment."
The Rukap.G backdoor Trojan, designed to allow attackers to take control of a computer, and the Dadobra.Bl Trojan were also among the most prevalent malicious code.
"For companies, spam is more than just a nuisance: It consumes bandwidth, wastes employees' time and can even cause system malfunctions. In the end, it all results in a loss of productivity," Matthews says.
Much of this spam was circulated by the extensive network of zombie computers controlled by cybercrooks. Just in the last three months of the year, 301 000 zombie computers were being put into action every day.
Regarding the different types of spam in circulation, 32,25% of spam in 2008 was related to pharmaceutical products with sexual performance enhancers accounting for 20,5%.
Spam relating to the economic situation also grew significantly throughout 2008. False job offers and fraudulent diplomas accounted for 2,75% of all junk mail in the year, while messages promoting mortgages and fake loans were responsible for 4,75%.
Spam promoting fake brand products was responsible for 16,75% of the total. This last category, however, dropped from 21% in the first half of the year to 12,5% in the last six months.