Symantec blocked more than 5.5 billion malicious attacks around the world in 2011, an increase of 81 percent over the previous year.

The mind-boggling statistic was released this week in the company’s annual report of the global cybersecurity threat landscape. Download the report here.

The security vendor’s threat analysts and researchers also shared that the unique number of malware variants has increased to more than 400 million and the number of Web attacks blocked each day has gone up 36 percent.

Furthermore, targeted cyberattacks are on the upswing too. Hackers are putting more effort toward using social networks and social engineering to gain unauthorized access to sensitive information. More individuals are clicking into bad links because of customized malware and other tricks.

“These advanced attacks have traditionally focused on public sector and government; however, in 2011, targeted attacks diversified,” Symantec said, explaining that smaller organizations and workers in nonexecutive roles are increasingly being targeted.

Cybercriminals are moving beyond spam, Symantec said. Spam “fell considerably” and newly discovered vulnerabilities decreased by 20 percent in 2011. Instead, hackers are turning to social networks to launch attacks.

“The very nature of these [social] networks makes users incorrectly assume they are not at risk and attackers are using these sites to target new victims,” the vendor said. “Due to social engineering techniques and the viral nature of social networks, it’s much easier for threats to spread from one person to the next.”

Data breaches resulted in the compromise of 187 million identities in 2011, Symantec said. In all, 232 million identities were stolen.

The rise of mobile devices likely will only make the problem more troublesome. Recent research by Symantec found that 96 percent of lost phones will suffer a data breach.

“With the number of vulnerabilities in the mobile space rising and malware authors not only reinventing existing malware for mobile devices, but creating mobile-specific malware geared to the unique mobile opportunities, 2011 was the first year that mobile malware presented a tangible threat to businesses and consumers,” Symantec said.