Facebook users to exercise caution about which third-party applications they install on their profile after a rogue application, 'Error Check System', bombarded some members of the social networking site with bogus notification messages saying that friends had experienced problems viewing their profiles.

Experts at IT security and control firm Sophos note that since Facebook does not approve applications before they are made available on the site, users are often putting their trust in complete strangers when they choose to install the next application.
In this instance, there was nothing wrong with the recipient's profiles and the warning messages were in fact a viral attempt by a third party to recruit more users, and – potentially – steal personal information for financial gain.
"Due to the popularity of Facebook applications, users are often tempted to follow suit when all their friends have downloaded the latest must-have," says Brett Myroff, CEO of regional Sophos distributor, Sophos South Africa. "However, installing all applications sent your way could open up serious security holes and allow hackers to gain access to profiles and the information stored on it."
As with other computing applications, users are advised to exercise caution when unsure of the origin of a notification.  "Just because your friends have downloaded an application, doesn't necessarily mean it's safe," says Myroff.
Sophos has produced Facebook best practice guidelines that offer advice on how to secure an online profile.