Experts at SophosLabs have warned of a new phishing email that attempts to trick PayPal users into calling a phone number and parting with their credit card information.

The email, which purports to come from PayPal, claims that the recipient's account has been the subject of fraudulent activity. However, unlike normal phishing emails, there is no internet link or response address. Instead, the email urges the recipient to call a phone number and verify their details. When dialled, users are greeted by an automated voice saying:

"Welcome to account verification. Please type your 16 digits card number."

Once the credit card details are entered, the scammer is free to steal the information for their own gain. If incorrect card details are entered, a request for re-entry is made, further enhancing the legitimacy of the fraudulent telephone number, which is still live.

"Users that type in their card information may think they're verifying their PayPal account, but in actual fact, they're handing their details over to cyber criminals on a plate," said Graham Cluley, senior technology consultant at Sophos. "Though it's an American telephone number, the fact that PayPal is used globally means that anyone could potentially be tricked into making the call."

"This scam underlines a real problem for online companies in how they communicate with their customers. Many users are beginning to learn not to click on links in unsolicited emails, and only visit legitimate websites, but how many would know whether a phone number for a website is genuine or not?" continued Cluley. "As hackers get smarter we are likely to see an increase in cases where, rather than setting up fake websites, they 'harvest' messages from corporate switchboard systems to sound even more like the legitimate company."

Sophos recommends users protect themselves with a consolidated solution which can defend them from the threats of both spam and viruses; and that they do not open or reply to unsolicited emails.