Dark Reading

VOIP's anonymous nature may be convenient, but it can also be used against you. Secure Computing today warned of a new phishing exploit on the loose -- dubbed "vishing" -- that uses voice-over-IP and good old-fashioned social engineering.

Santa Barbara Bank & Trust and PayPal were the first to fall prey to vishing, where an attacker telephones a credit-card customer automatically, with a war dialer or directly, and dupes him or her into revealing account information by claiming there's been fraudulent activity on their account. The victim is then instructed to dial a "bad" phone number that then prompts them to enter their account number.

On Friday, an email posing as a PayPal message was circulating with a phone number for credit card customers to call, akin to the type of message Santa Barbara Bank & Trust customers recently received.

Paul Henry, vice president of strategic accounts for Secure Computing, says attackers are finding it's easy to hide behind VOIP numbers from any geographic location they choose. "Anyone can open a Skype account, get a dial-in number, and work from anywhere in the world," Henry says. "And they can have any specific regional dialing prefix they want…VOIP is so anonymous."

War dialing with VOIP is very simple: An attacker can use open source PBX software or a Windows app, and with a little minor scripting, configure a PBX to use Skype and make the calls, Henry says. "Doing it over VOIP is incredibly simple and lets them remain anonymous."

There is no tool that protects you from such an attack, which is more social engineering than technology, anyway.

Henry says Secure Computing has been monitoring several newsgroups over the past year that have been talking about this form of attack, and that Secure Computing felt it was time to educate users about the threat.

"We've finally gotten it in our heads not to click on URLs, but this is the next evolution of phishing," Henry says. "You'll find a lot of people will dial that number. They are used to credit card companies sending a notice to call and verify account information."

The most important way to protect yourself is to always call the phone number on the back of your credit card or the bank itself, not any number a third party provides you, he says.

— Kelly Jackson Higgins, Senior Editor, Dark Reading