Facebook has largely erased the rash of porn and violent images that affected the site earlier this week, but its problems are far from over, researchers said yesterday.

In a blog about Facebook's security vulnerabilities posted Thursday, researchers at security vendor Barracuda Networks said Facebook still has little incentive to improve its site security.

"When you are trying to grow a social network as well as increase advertising revenue, security becomes not only a lower priority but sometimes a conflict of interest," the blog states.

Facebook continues to miss some key security issues on its pages, Barracuda says, and it outlined seven:

1. Fake product pages. "Knock-off luxury goods have always been popular scams," the blog notes. "If you actually get the product, which is a bit of a longshot, you are likely to find that the quality you expected from the brand is lacking at best. Facebook is rife with pages promoting these goods."

2. Manipulated accounts recommendations. "On social networks, those with less good motives have figured out how to game the recommendation system and use it to their advantage," the blog says. "This is very similar to how attackers have used search engine optimization to promote their malware. Friends are recommended in a variety of ways, but a simply exploited example is through shared apps. Spammer accounts sign up for the same popular apps that real users do and before too long they are showing up in your list of recommended friends."

3. Affiliate spam. "Affiliate spam is a bigger and bigger part of the typical users incoming stream," Barracuda states. "They encourage or require the user to share it out to all their friends and say something like 'I love Olive Garden' before being redirected to a never-ending series of offers."

4. Photo tagging for spam. "Photo tagging for spamming is one of the most popular methods of spamming through the network, but it doesn’t seem to be getting much attention," the blog says. "With each image uploaded, a spammer can tag as many 50 other accounts in a photo, and have as many as 200 photos in an album. With everyone in Facebook having a maximum of 5,000 friends, each photo can reach a quarter million people."

5. Fake Apps. "Fake apps, malicious apps, misleading apps, whatever you want to call them, Facebook is overflowing with them," the blog observes. "Usually these apps are in the information gathering and spamming business, but we have found examples that link to malicious binaries."

6. Stolen pictures."There is not really a set of sextuplets, each with the same bikini picture as their personal profile picture," Barracuda quips. "Those are fake accounts. Certainly there are some images that will be common to multiple people, such as a team logo or newly released album cover. However, the fake accounts typically use images of a salacious nature."

7. Anomalous behavior. "Finally, Facebook and social networks in general should focus on some form of anomaly detection," the blog advises. "We’ve all seen examples of that friend who you never really talk to, and probably weren’t that interested in 'friending' anyway, posting on your wall or messaging your account encouraging you get a free iPad or a trip on Southwest airlines. Similar problems have been appropriately mitigated elsewhere in messaging but social networks have a long way to go."