Wondering if your credit card number could be in the hands of a crook? Look for a charge for $9.84.

Earlier this year, the Better Business Bureau issued a fraud alert about a raft of consumer complaints all reporting the same niggling charge. The business levying this fee may purport to provide "customer support," or it may simply identify itself as any one of a number of different websites.

The fraud, uncovered by a former Washington Post reporter who writes an investigative blog called KrebsOnSecurity, apparently relies on consumer carelessness. Where an unfamiliar charge for a large amount would be spotted by most consumers, little charges can go unnoticed.

Get Breaking News Delivered to Your Inbox

Krebs writes in his blog that the charges, most of which were reported over the past holiday season, may have been spotted because consumers are being more vigilant in the wake of the Target breach. His investigation into the fees led him through a labyrinth of 230 websites that were all connected to one of a handful of individuals located in London, India and Cyprus.

The bottom line for credit card customers is a simple one: If you spot a charge for $9.84 on your credit card statement, call the card issuer. It's likely that your card or card number is in the hands of a crook. You need a new card and to place a fraud alert on your credit file.

Placing a fraud alert on your credit file is simple (and explained here by the Federal Trade Commission). It should only require reporting the fraud to one of the three credit bureaus. The credit bureau that you report to should spread the news to the other two major bureaus on your behalf.

And in case you're not already doing this, keep a close eye on your accounts. As massive breaches over the past year demonstrated, credit card security is far from foolproof. Your best defense is vigilance.

This post was originally published on Jan. 27, 2014.