Criminals are getting smarter and smarter. So, these days, it isn't enough to just run security software on your computer. You need to keep up with the criminals' latest tricks. Here are six threats to your security and tips for protecting yourself:

FLASH DRIVES

Flash or thumb drives provide an easy way to infect machines with malware. It's no surprise that criminals are using them, particularly to target companies.

Criminals use a flash drive with a company's logo. They load it with malware and drop it in the company's parking lot. An unsuspecting employee picks up the drive and connects it to his or her computer. What happens next is the scary part. Criminals gain access to the company's network — and trade secrets.

FACEBOOK 'FRIENDS'

Everyone seems to be on Facebook. It can be exciting to find new Facebook contacts. But pay close attention to who you grant access to your profile.

If you use your account for business, it can be a gold mine for competitors. You may unknowingly post information about projects that would benefit competitors. Even your contact list says a lot. It can give hints about an upcoming merger or partnership. It can also give criminals inroads at other companies. Limit what others see and be careful about your posts. You may also prevent others from posting to your wall. Above all, be vigilant.

CLICKJACKING

Clicking on malicious links is known as clickjacking. It can happen anywhere online. Most notably, it threatens Facebook and Twitter users. A victim is lured to a malicious page. The victim's profile page is opened behind the malicious page. The victim has no idea any of this is happening..

There is no certain way to protect against clickjacking. Your best bet is to watch for suspicious links or sites. Be alert.

SMART PHONE APPS

Smart phone apps are hot. Criminals are looking to them to get your information. Apple checks apps before offering them to users. But other app stores may be less thorough.

For example, one developer recently offered banking apps for Android phones. The developer had no ties to the banks. The apps may have been password-stealing tools.

Although it's less likely, apps could also infect a phone with malware. Even seemingly legitimate apps pose risks. They may collect location information or access information stored on the phone.

E-MAIL MESSAGES

E-mail has long been a popular method of attack. And e-mail attacks are improving. Obviously, beware of attachments. If you're not expecting an attachment, call the sender. Verify that it is legitimate.

Watch out for links in e-mail messages as well. These can take you to attack sites. Links to videos are particularly popular. You may be prompted to download something to display the video. You can bet it's a Trojan.

PORN DIALERS

Porn dialers are making a comeback on cell phones. The dialers are Trojans posing as videos, software or utilities.

They affect phones that run Java. Many are found on porn sites. Once installed, they send premium text messages or call premium numbers without your knowledge. You're hit with a whopping bill.

Don't download anything from unknown or untrusted sources.

You could also receive links to premium numbers via text message. Be careful when texting or calling numbers sent to your phone.