There has been an alarming rise in attacks on users of social networks, such as Facebook and Twitter, by cybercriminals.

The newly-released "Social Security" investigation by IT security and data protection firm, Sophos, reveals that criminals have increasingly focused attacks on social networking users in the last 12 months, with an explosion in the reports of spam and malware.
According to the report, 57% of users have been spammed via social networking sites, a rise of 70,6% from last year, while 36% reveal they have been sent malware via social networking sites, a rise of 69,8% from last year.
"Computer users are spending more time on social networks, sharing sensitive and valuable personal information, and hackers have figured out where money is to be made," says Brett Myroff, CEO of regional Sophos distributor, Sophos South Africa. "The dramatic rise in attacks in the last year tells us that social networks and their millions of users have to do more to protect themselves from organised cybercrime, or risk falling prey to identity theft schemes, scams and malware attacks."
Sophos surveyed more than 500 organisations, and discovered that 72% are concerned that employee behaviour on social networking sites exposes their businesses to danger, and puts corporate infrastructure – and the sensitive data stored on it – at risk.
The "Social Security" survey is part of Sophos's 2010 Security Threat Report, which explores current and emerging computer security trends.  It reveals that criminals identify potential victims on social networks, and then attack them, both at home and at work. In Sophos's opinion, many Web 2.0 sites are concentrating too much on growing their marketshare at the expense of properly defending their existing users from internet threats.
Survey respondents were also asked which social network they believed posed the biggest security risk, with 60% naming Facebook; 18% naming MySpace; 17% saying it's Twitter; and 4% LinkedIn.
"Facebook is by far the largest social network. While its security team works hard to counter threats on their site, policing 350 million users can be a tough job for anyone,” says Myroff. “There is no doubt that simple changes could make Facebook users safer.  For example, when Facebook rolled-out its new recommended privacy settings late last year, it was a step backwards, encouraging many users to share their information with everybody on the internet."
Sophos's Threat Report also reveals that 49% of companies allow all their staff unfettered access to Facebook, a 13% rise on a year ago.
"The irony is that just as companies are loosening their attitude to staff activity on social networks, the threat of malware, spam, phishing and identity theft on Facebook is increasing," Myroff says. "However, social networks can be an essential part of the business mix today, and the answer is not to bar staff from participating in them but to apply some 'social security' instead."
Although LinkedIn is considered to be by far the least threatening of the networks, Sophos advises that it can still provide a sizeable pool of information for hackers.
"Sites like LinkedIn provide hackers with what is effectively a corporate directory, listing your staff's names and positions. This makes it child's play to reverse-engineer the email addresses of potential victims," Myroff adds.