According to a recent security report, there has been a marked increase attacks aimed at popular sites such as Facebook and MySpace where users share everything from contact details to detailed life histories.

The latest Symantec Internet Security Threat Report, a global review of online threats, has found such sites are being used by criminals to steal personal financial information or to match personal details with credit card numbers stolen from other sites.

Symantec’s Pacific vice president Craig Scroggie says the sites can sometimes even provide sufficient personal details so that a criminal can apply for a credit card as though they are that person.

“Business is booming in the underground economy,” he says. “We are particularly seeing a lot of attention focused on trusted web sites where people feel comfortable about sharing a lot of personal information.”

Scroggie says there has been a marked maturing in this black economy during the past six months, to the point where it can now be categorised as an “orthodox economy”.

“It has taken on all the characteristics of a mature economy, where prices vary depending on supply and demand economics,” he says. “They are also getting a lot better at detecting security measures.”

As well as stealing personal details from online profiles, the report found attackers are using social networking sites to distribute malicious code.