Some of the most successful and lucrative online scams employ a “low-and-slow” approach — avoiding detection or interference from researchers and law enforcement agencies by stealing small bits of cash from many people over an extended period. Here’s the story of a cybercrime group that compromises up to 100,000 email inboxes per day, and apparently does little else with this access except siphon gift card and customer loyalty program data that can be resold online.
The data in this story come from a trusted source in the security industry who has visibility into a network of hacked machines that fraudsters in just about every corner of the Internet are using to anonymize their malicious Web traffic. For the past three years, the source — we’ll call him “Bill” to preserve his requested anonymity — has been watching one group of threat actors that is mass-testing millions of usernames and passwords against the world’s major email providers each day.
Bill said he’s not sure where the passwords are coming from, but he assumes they are tied to various databases for compromised websites that get posted to password cracking and hacking forums on a regular basis. Bill said this criminal group averages between five and ten million email authentication attempts daily, and comes away with anywhere from 50,000 to 100,000 of working inbox credentials.
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You might think that whoever is behind such a sprawling crime machine would use their access to blast out spam, or conduct targeted phishing attacks against each victim’s contacts. But based on interactions that Bill has had with several large email providers so far, this crime gang merely uses custom, automated scripts that periodically log in and search each inbox for digital items of value that can easily be resold.
And they seem particularly focused on stealing gift card data.
“Sometimes they’ll log in as much as two to three times a week for months at a time,” Bill said. “These guys are looking for low-hanging fruit — basically cash in your inbox. Whether it’s related to hotel or airline rewards or just Amazon gift cards, after they successfully log in to the account their scripts start pilfering inboxes looking for things that could be of value.”
A sample of some of the most frequent search queries made in a single day by the gift card gang against more than 50,000 hacked inboxes.
According to Bill, the fraudsters aren’t downloading all of their victims’ emails: That would quickly add up to a monstrous amount of data. Rather, they’re using automated systems to log in to each inbox and search for a variety of domains and other terms related to companies that maintain loyalty and points programs, and/or issue gift cards and handle their fulfillment.
Why go after hotel or airline rewards? Because these accounts can all be cleaned out and deposited onto a gift card number that can be resold quickly online for 80 percent of its value.
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Bill’s data also shows that this gang is so aggressively going after gift card data that it will routinely seek new gift card benefits on behalf of victims, when that option is available. For example, many companies now offer employees a “wellness benefit” if they can demonstrate they’re keeping up with some kind of healthy new habit, such as daily gym visits, yoga, or quitting smoking.
Bill said these crooks have figured out a way to tap into those benefits as well.
“A number of health insurance companies have wellness programs to encourage employees to exercise more, where if you sign up and pledge to 30 push-ups a day for the next few months or something you’ll get five wellness points towards a $10 Starbucks gift card, which requires 1000 wellness points,” Bill explained. “They’re actually automating the process of replying saying you completed this activity so they can bump up your point balance and get your gift card.”
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several large Internet service providers (ISPs) in Germany and France are heavily represented in the compromised email account data.
“With some of these international email providers we’re seeing something like 25,000 to 50,000 email accounts a day get hacked,” Bill said. “I don’t know why they’re getting popped so heavily.”
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Source: Gift Card Gang Extracts Cash From 100k Inboxes Daily – Krebs on Security
Robin Edgar
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