New research published by Sophos today reveals a 70 percent increase in the number of companies reporting spam and malware attacks via social networks.

The study, included in Sophos' "Security Threat Report 2010," shows that 57% of social networking users have reported receiving spam (compared to 33.4% a year ago).

In the same period, the number of those reporting social networking malware attacks rose from 21.2% to 36%.

So why the rise?

Well, computer users are spending more time than ever on social networks, sharing sensitive and valuable personal information. It's no surprise, therefore, that hackers have determined where the money is to be found.

And the cybercriminals don't just want to infect your computer via social networks to steal your online banking details. Increasingly, they're after data that could help them compromise your organization.

Sophos' poll of more than 500 companies reveals that 72% of firms are worried that workers' behavior on social networks is putting their business at risk. Corporate infrastructure -- and the sensitive data stored on it -- is in danger if not properly secured.

What's fascinating is that despite the rising fears of social networks, 49% of firms have given permission to all of their staffs to access Facebook at anytime during the day, a 13% rise on a year ago.

Indeed, Sophos' research indicates that for those companies that do apply restrictions, productivity -- rather than malware or data leakage -- continues to be the No. 1 reason for blocking access to Facebook:

Social networks are an essential tool for many companies today, giving them an opportunity to be closer to their customers and build a community around their brand. For that reason, it's becoming harder and harder to block social networks from inside companies. And even if blocks are put in place, are you confident that your staff won't attempt to waltz around them?

My feeling is that social networks are here to stay; we have to accept them and secure them the best we can. That means deploying technology to scan every Website and link clicked on by users, educating staff about the safe use of social networks, and calling on the networks themselves to increase their protection against threats.

If this isn't done, then we'll all be facing the grim irony that just as companies are loosening their attitude to staff activity on social networks, the threat of malware, spam, phishing, and identity theft will become ever greater.

Much more information can be found about the study, as well as in the way of trending security threats, in Sophos' Security Threat Report 2010.

Graham Cluley is senior technology consultant at Sophos, and has been working in the computer security field since the early 1990s. When he's not updating his award-winning other blog on the Sophos website, you can find him on Twitter at @gcluley. Special to Dark Reading.