Social networking sites like Facebook, Bebo and MySpace have soared in popularity over the last few years. They allow users to keep in touch with their friends and make new friends, but they can also expose them to malware and other online danger. As usage of Web 2.0 applications, like blogs, wikis and social networking sites increases, they become more attractive to cyber criminals. Many users of these sites are relatively new to computers and can sometimes be fairly nave regarding online threats.

Many of the threats discussed in this article are historical. They have now been countered by site owners, but new ones will appear as attackers develop their methods in response to improved security. Social networking sites can spread threats very quickly, due to their interactive nature. This makes them very attractive as targets. Many threats take advantage of the fact that people trust their friends, and fail to realize how important it is to treat electronic communications with care, irrespective of their apparent source.

As with other aspects of Internet use, threats can be split into two categories: behavior-based and technology-based.

Threats Posed by Behavior

Behaviour-based threats arise largely because users are careless regarding the personal information they share online. This can leave them vulnerable to phishing attacks and identity theft. Users often publish details of their friends, their likes and dislikes, hobbies and jobs, without realizing that this information can be invaluable to identity thieves as it can help them appear more credible.

After carrying out research on a random sample of Facebook users carried out by Sophos, an IT security company, showed that 41% were prepared to give out personal information like as email address, date of birth and phone number to a complete stranger. The researchers created a fictitious Facebook profile for a green plastic frog named Freddi and sent out 200 friend requests to random users all over the planet. 87 of the users contacted replied and 82 of them supplied personal information, like email addresses, date of birth, details about their education or workplace, address and phone number, as well as photos of friends and family and information about partners, hobbies and likes and dislikes.

In 2007 Internet Safety website Get Safe Online found that a quarter of UK social networking users had posted confidential personal information, such as their address or phone number on their social networking profiles. 13% of them had posted information or photos of other people online without their knowledge. This figure increased to a worrying 27% among users aged 18-24.

Threats other than phishing can found on social networking websites. Eleven Canadian high school were suspended after making comments about their principal on Facebook when the school imposed a ban on electronic devices and implemented a uniform policy. A school spokesman claimed that the comments constituted cyber-bullying and described them as vulgar and profane.

There have been several allegations that young girls have been raped by older men who encountered them via MySpace or Facebook, but none of these appear to have been conclusively proved. The real issue appears to be that social networking sites can provide an opportunity for men to meet young girls in an unsupervised environment, a situation that parents ought to be very wary of.

Technology-Based Threats

Social networking sites can also be a source of technology-based threats. They allow millions of people to post content, so it’s inevitable that some of these will be malicious individuals attempting to post malware.

Early in 2008, more than three million Facebook users were infected with spyware in less than four days. A Facebook widget named “Secret Crush” or “My Admirer”, reportedly downloaded by one and a half million users, claimed to tell users who had a secret crush on them, but actually tricked them into downloading the well-known Zango spyware. It spread by prompting users to forward the widget to five friends.

Anti-virus vendor Symantec has claimed that vulnerabilities which could be used by hackers to snatch control of Windows PCs have been found in ActiveX controls offered to users by both Facebook and MySpace for uploading images to their pages via Internet Explorer (IE). The insecure controls are based on an ActiveX control named Image Uploader, produced by Aurigma Inc.

Towards the end of 2005, 19-year old Samy Kamkar wrote a worm that infected more than a million MYSpace users and caused the site to shut down. The Samy worm added a million friends to his profile within a few hours, adding the string “but most of all, Samy is my hero” to each of their profiles. Kamkar was later sentenced to three years probation and made to perform 90 days of community service.

In January 2008 a 17-gigabyte file containing more than half a million pictures obtained from private MySpace profiles appeared on BitTorrent, a well-known peer-to-peer file sharing service. This is biggest privacy breach to date on a social networking site. It was made possible because a security vulnerability, first reported in Autumn 2007, allowed hackers to access the photo galleries of some MySpace users who had set their profiles to private. This is the default setting for users aged under 16. This attack allowed pedophiles and voyeurs to target vulnerable 14- and 15-year-old users.

Brazilian users of Google’s Orkut application were attacked in December 2007 by a worm that attempted to take control of their computers and steal their bank account details. It spread via booby-trapped links placed on the personal page of Orkut users and infected users when they viewed messages that came from friends who had already been exposed.

Google was quick to close the loophole which allowed the attack to take place, but another worm, named Scrapkut, appeared early in 2008. It appeared relatively harmless at first, but it was soon determined that it could intercept the login sessions several Brazilian banking Web sites and replace particular sections with a fake authentication prompt which would capture the users’ logon credentials.

YouTube has also been used indirectly to spread malware. There was a spate of spam messages which asked users to click on an attached YouTube video clip. The link took them to a false YouTube site where they were told that they needed to install Adobe Flash Player to play the video. Clicking the supplied link caused a file called install_flash_player.exe to be downloaded. This is the same name as the real Flash installer, but it actually installed a Trojan known as Trojan-Dropper.W32/Agent.

Countering Threats

We’ve looked at some of the dangers you need to guard against on social networking sites, but what can you do to protect yourself against them? Technology-based attacks can often be repelled by the usual software defenses, ie: anti-virus software can prevent infection by viruses, trojans and worms, and anti-spyware programs can protect you against spyware and adware. A top-quality firewall (remember that the one supplied with Windows XP is fairly basic) can protect you against hackers and Internet safety suites can offer protection against a range of threats.

Behavior-based attacks, which rely on tricking users into behaving unwisely, are harder to deal with as they can only be tackled by a change in user behavior. Get Safe Online provides a number of guidelines for networking safely, including the following:

Don’t allow peer pressure to push you into doing something you’re uncomfortable with.

Avoid posting information that could identify you, such as telephone numbers, photos of your home, workplace or school, your address, date of birth or full name.

Avoid including personal information in your username, eg: use laughing_boy33, rather than jim_brown.

Set up a free email account (eg: Yahoo or GMail) that doesn’t resemble your real name and use that to register and receive mail from the site.

Use a strong password.

Avoid making comments or publishing photos which could embarrass you later.

Use the privacy features on the site to restrict strangers’ access to your profile.

Watch out for phishing scams.

If you make sure that your software defenses are strong and up-to-date and you follow the above guidelines you should be able to enjoy social networking without problems.

If you have young children you should ensure that they are not allowed access to the Internet in an unsupervised environment. It’s much better if the computer is in a family area, such as a lounge or dining room, rather than hidden away in a bedroom. Even with older children you should try to keep an eye on their Facebook or MySpace profiles and watch out for any changes in behavior which may suggest that they are encountering online problems.