Symantec Corporation’s new Internet Security Threat Report paints a bleak picture of Web security.

According to the report, cyber-threats are skyrocketing in volume as well as sophistication. The report placed the US at the top in the list of cyberbads.

In 2010, the US accounted 19 per cent of total overall malicious activities, 22 per cent for originating network attacks, 14 per cent for the most bot-infected computers, 37 per cent for the most bot command-&-control servers, and a whopping 65 per cent for being the most targeted country by denial-of-service attacks.

Symantec warned that the number of cyber attacks jumped 93 per cent from 2009 to 2010. The Internet security specialist also warned that sites containing porn are the most likely source of malware. According to the report, pornographic sites accounted for 49 per cent of all malicious websites last year.

In 2010, as many as 6,253 software vulnerabilities were reported, more than in any other previous year. A total of 14 vulnerabilities were used in zero-day attacks, with infamous Stuxnet attack accounting for 4 of these Windows zero-days.

At one point in 2010, Rustock botnet was controlling more than 1 million computers. Two other botnets, viz. Cutwail and Grum, also had hundreds of thousands of systems under their control.