Crooks are targeting consumers who use their credit and debit cards to pay at the pump. In a warning sent out by Visa, the company said they’ve identified three separate and sophisticated attacks carried out against point-of-sale systems.

You may have heard of crooks installing skimmers on gas pumps or ATMs to trick people into inserting their cards into fake hardware that steals their information, but these attacks are way more sophisticated. These crooks actually attack the software that runs on cash registers and gas pumps.

In one case, the crooks used the oldest trick in the cyber-crime book to get into the system, they sent a phishing email to an employee of the merchant. The employee clicked on a link that downloaded malware that got into the company network and started stealing payment details like card numbers.

The second attack targeted fuel pumps that accepted non-chip credit and debit cards and managed to intercept the data from magnetic strip cards as it was being sent from the pump to the gas station’s servers.

Visa is suggesting that gas stations be on the alert, tighten their cyber-security measures, and consider switching to pumps that only accept chip cards.

As for consumers, your best bet is to carefully monitor your credit and debit card statements for anything unusual and, if possible, consider paying for your gas with cash.