Security firm Cloudmark claims a new set of SMS attacks that direct victims to phishing answering machines has boomed in recent days.
The attacks began last Tuesday and direct victims to call spurious numbers thought to be banking institutions, credit card services or even government agencies.
Most victims would be answered by a machine setup to request personal details. Messages typically read “attention required” with a phone number.
Cloudmark senior security researcher Mary Landesman told SC phishing ruses were the most common SMS-based attack seen by her firm.
The most common previous SMS attacks included free gift card and giveaway scams directing victims to online surveys linked to registrations for premium rate SMS messages.
Scammers were likely obtaining victims' numbers from virtual number providers, according to Landesman.
“[Victims] believe that if they have a phone number, and it's not widely known, it wouldn't be likely for someone to send a [malicious] SMS,” she said.
“The person thinks their number is private, and then they think that it's from a trusted source, so the attackers are playing a game of odds.”
Cloudmark published the phone numbers in a blog post.