Your gift cards are a top target for scammers this holiday season

You might want to check the balances on the gift cards your extended family gave you last Christmas.

That's because gift card fraud is becoming more and more common among financial scammers, according to security experts. While consumers are now primed to routinely check their credit card reports and statements for mysterious transactions, it isn't often the same for gift cards, making it harder to catch thieves in real time.

"Who checks their gift card balances on a daily basis?" Rick McElroy, principal security strategist at VMware Carbon Black, a cybersecurity firm, told CNBC Make It. "Thieves get a lot longer to hide."

There are multiple gift card scams that are becoming increasingly popular, according to security experts.

One involves scammers using a card reader to record — or simply writing down — a card's serial number in store before it is sold. Then, they scratch off the decal protecting the cards' PINs and record those, too, replacing the covering with tape that can be bought relatively cheaply online, according to Krebs on Security, a popular tech security blog.

"Once a card is activated, thieves can encode that card's data onto any card with a magnetic stripe and use that counterfeit to purchase merchandise at the retailer," writes Krebs. "Meanwhile, the person who bought the card (or the person who received it as a gift) finds the card is drained of funds when they eventually get around to using it at a retail store."

Other scammers use bots to test out millions of combinations of gift card numbers and PINs on retailer websites. Once they access an account, they drain the money still left on the cards, either by selling it on the dark web or buying products or services themselves.

It's not just gift cards. Thieves are using similar tactics to access member accounts on retailer websites to steal any loyalty points the member may have accumulated (think Sephora's Beauty Insider points), Edward Roberts, director of product marketing for bot management at Imperva, a cybersecurity firm, tells CNBC Make It.

"Most customers don't have much in the account, but the loyalty points and the credit card information are the crown jewels they're after," says Roberts.

While scammers will always devise new tactics to steal information and money, Roberts says, there are a few basic things customers can do to protect themselves.

To avoid buying a compromised card, study the bar codes and decals covering the PINs on gift cards for signs of tampering or completely exposed PINs. Buying cards from stores that keep cards behind, or close to, the counter is also smart, because they will be harder to tamper with.

A better option, according to experts: Buy gift cards online, not in person. Scammers can't access these as easily.

If you are given a gift card this holiday season, use it as soon as possible to avoid loss or theft, suggests Roberts. You can also register your gift card and change the PIN.

Make sure you're not using the same username and password for accounts across retailer websites, Roberts says. Keep tabs on the amount of money left on your gift cards and the amount of loyalty points you have, so that if fraud does occur, you know the time frame it happened in and can report the details to the necessary regulatory bodies, like the FTC.

"The incentive for the bot operator is they are making money doing this and being successful, so they're going to keep coming back," says Roberts. "It keeps escalating. You have to be vigilant on this problem, it's not a one-time solution that solves it."

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