If you fell victim to a phishing scheme or another hack attack, it's likely that someone else has obtained your password and is using it to access your account. You'll need to change your login credentials ASAP. Visit your Facebook's Account Settings to do this. Remember, don't reuse passwords on different accounts and the more complex the password, the safer you'll be.
If you believe someone has gained access to your Facebook profile and is posting unauthorized content in your name, Facebook's Roadblock tool can help verify your identity and secure your account against the spammer.
Enable Login Approvals
One of Facebook's new security features will implement a two-step login process the first time your account is accessed from an unfamiliar device. If you enable this feature, Facebook will send a verification text to your mobile device before allowing access from the new location. You can save or block the new device via your handset. If a foreign device fails to log in, Facebook will notify you when you next log in from one of your approved devices and will give you the option of resetting your password if you suspect foul play.
Clean Out Your Applications
When you approve a normal app, you "allow" the app access to your profile, trusting that the developers will post only updates about your in-app activities. However, spammers will use this open door to take over your profile. If you fell for a rogue app and mistakenly clicked "Allow," or if you notice excessive activity on your account, you should edit your list of apps and remove any suspicious ones. To do this, open the drop-down box under your Account tab, click "Privacy Settings" and find the "Apps and Websites" settings management tool (at the bottom of the page). This tool will help you manage your apps and the kind of information they can access. Your Apps Page lets you turn off all platform apps or remove/edit each app individually. It's a good idea to use this tool every now and again, since apps tend to pile up over time.
Delete Spam Messages And Posts
As soon as you can, delete spammy posts from your wall and Facebook inbox. The fewer there are, the less likely you or your friends will be to click on them.
Edit Your Interests
If you were tricked into "Liking" a scam, you'll need to edit your interests on your profile and remove any links to spam sites you may have acquired.
Notify Facebook Staffs
If you suspect your account has been compromised, you can alert Facebook through several channels. To report privacy breaches, you can direct reports to firstname.lastname@example.org. If a scammer gained access to your account password via phishing attack, you can fill out Facebook's phishing report. Facebook also provides a separate form for reporting a malicious link or website.
If you've entered a line of malicious code into your browser and believe that someone has taken control of your profile and is in the process of spamming your friends, log out of Facebook to stop the attack. One of Facebook's new security features may also notify you of suspicious activity on your account, such as excessive "Likes" or posts.