Barracuda Labs researchers say they've recently seen an increase in the volume of a long-running scam that leverages spam e-mails promising weekly payments in exchange for the right to wrap the recipient's car in an ad for a popular product such as Monster Energy Drink, Coca-Cola or Budweiser.

"Monster Energy Drink seeks people -- regular citizens, licensed drivers to go about their normal routine as they usually do, only with a big advert for 'Monster Energy Drink' plastered on your car," the e-mail states. "The ads are typically vinyl decals, also known as 'auto wraps,' that almost seem to be painted on the vehicle, and which will cover any portion of your car's exterior surface. This program will last for 3 months and the minimum you can participate is a month. You will be compensated with $300 per week which is essentially a 'rental' payment for letting our company use the space."

"The e-mail looks reasonable," notes Barracuda research scientist Dave Michmerhuizen. "No funny links or attached files, just an offer written in plain English and an e-mail address."

If you pursue the offer, you'll be sent a check in the mail, along with instructions to forward a portion of the value of the check via Western Union to the person who'll apply the decal to your car.

"The mention of Western Union should be a huge red flag," Michmerhuizen writes. "Money sent via Western Union can be picked up anywhere in the world and the company offers no recourse if the payment was solicited fraudulently."

And in this case, the check that's sent to you is fake, and any money you sent via Western Union will have gone to the scammers.