These apps could be causing robocalls, scams, and unwanted phone calls

HARRISBURG, Pa -- If you search "call blocker" in your smartphone's app store, you'll find dozens of different apps claiming to stop robocalls, scams and other unwanted phone calls.

"You have to be mindful of which applications you download, some of them might actually be scams in and of themselves," said Andrew Hacker, a cyber security expert from Harrisburg University.

He says these apps have been popping up over the past few years and they all use a similar way to block those calls - crowdsourcing.

Apps like TrueCaller, Hiya and Mr. Number have created a sort of database of spoofed numbers between app users.

When you get a spam call, you report that number to the app.

That way, the next time someone who has the app gets a call from that number, it will be marked a spam.

There is a catch though.

Hacker says people who make these robocalls have a system that is able to disguise as various different phone numbers.

"That's actually a computer that can randomly just dial through every number in the phonebook."

There's another catch too.

The cyber security expert says there is almost no way to tell if these scam blocker apps are scams themselves!

Some people say they've received even more spam calls after signing up for certain apps.

Hacker suggests checking the number of downloads and the reviews before downloading one of these apps.

"I'm not going to download this app because it's actually requesting access to my contact list. So that would be a big red flag."

Hacker says there is an easy way to cut back on the number of spam calls you received - stop giving out your number!

He says giving your number at stores when you check out or signing up for contests with your phone number makes it more likely for you to get spammed.

That's because you don't know which one of those companies could be selling your information to third parties.

"There's really no need to give your number out. They might say they need it for something, but you really don't have to give it out," said Hacker.

Since these apps rely on crowdsourcing and there's no true technology in the works that can determine in a phone call is spam or not, Hacker believes this form of spamming won't stop anytime soon.

"As things move more and more towards computers and the old style phone numbers get less used, it's possible it might not as big of a problem and the problem just moves to the other platform."

So after checking out the pros and cons for all these apps, we asked Hacker if he would download one to stop robocalls on his smartphone.

"I wouldn't do it unless I had a real strong need to do it," he said.

Now, if you're getting a lot of these calls, you make sure your cellphone is signed up on the do not call list.

Also, you can report these spam calls to the attorney general's office too.

Only problem though, is experts say so many of these calls originate from outside of the United States, so it's unlikely these spammers and scammers will ever be caught.