More and more fraudsters are harvesting the log-in data of Facebook members in order to impersonate them and ask their friends for money, according to the social-networking company.

The scammers use phishing techniques to trick Facebook members into providing log-in information. For example, fraudsters often send legitimate-looking e-mail messages purporting to be from Facebook that ask members to visit a Web page and enter their log-in credentials.

They also post messages on members' profile Walls with links to supposed video clips or photos that really lead to phishing Web sites.

Once scammers can log in to someone's Facebook account, they often engage in what Facebook calls a "419" scam: pretending to be the member, they send messages to the person's friends asking for money.

In a "419" scam, fraudsters usually ask that the money be wired to them using Western Union, saying they're stranded and penniless in a foreign country.

There has been an increase in "419" scams recently, although the number of Facebook members who have been affected remains low, the company said Tuesday in its official blog.

Facebook is working with Western Union to raise awareness about the scam, implementing technical measures to better detect and deal with the issue and collaborating with law enforcement agencies and e-mail providers to identify the criminals.

It's no surprise that cyberthieves are attracted to Facebook, where more than 300 million members worldwide post a lot of personal information, much more than on other sites.

If malicious hackers gain access to someone's Facebook profile, they will likely learn not only the person's full name, but probably also their date of birth, place of employment, education history, marital status, phone numbers and addresses, as well as get the chance to contact hundreds of family members, friends and professional acquaintances.

Even if someone's Facebook account isn't compromised, security experts warn people to be careful about the information they post on their profiles and who they share it with.

Although Facebook gives its members very granular access controls over their profile content, the company has admitted that its privacy features can be confusing to understand and complicated to manage.

For that reason, Facebook announced in July that it would simplify its privacy options, an initiative that is still in progress.