Hackers are growing even more bold extending their ransomware attacks beyond businesses and even targeting police departments. Police departments across the United States have fallen victim to ransomware attacks that encrypt documents and demand payment in order to release their lockout.

Over the weekend, some police agencies in Maine reported having to pay a ransom to hackers in order to keep their files. In Tewksbury, Massachusetts, the police chief said he had to pay $500 to get back his department's valuable data.

The scheme has become more sophisticated over the past decade and has found a niche targeting law enforcement, according to Robert Siciliano, an online safety expert to Intel Security.

"It's a multi-million dollar business," he said. "They're getting paid and they're getting paid well."

Ransomware can infect a computer if the recipient clicks a link that contains dangerous code. These links often masquerade as nothing more than a benign attachment and pretend to be something they are not in the hopes of fooling the user into clicking them. Users who use computers with out of date browsers or not anti-virus software are most at risk for these types of attackes.

"When they are attacked they usually see a countdown screen, a clock counting down the time they have until the offer expires and their data is deleted," Siciliano said.

Ransomware has become a growing threat to businesses over the last year and has become an effective way for hackers to make money off of unsuspecting users. Once you are infected, you will not be able to access your valuable files on your computer until the infection has been removed. In many cases, computer users are forced to turn to backups or just pay the ransom.

The best defense against these attacks is keeping good backups of all your files. In addition, one should consider updating any out of date software and always maintaining strong, up to date anti-virus software. However, if you do become infected, you may be forced to make a choice. If you don't have good backups in place, unfortunately you may be tempted to pay the ransom. The problem is paying the ransom is no guarantee that your files will be unlocked, although many companies and now police departments have actually paid the money in order to regain control of their files.

"If you stand to lose more than the ransom might cost, then certainly it's a consideration," Siciliano said. "But the thing is, if you're proactive and backing up your data in multiple locations then you have less to worry about."