Cybercrime Gift Card Gang Extracts Cash From 100k Inboxes Daily

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Jul 27, 2015
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Quote : " 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.

In about half the cases the credentials are being checked via “IMAP,” which is an email standard used by email software clients like Mozilla’s Thunderbird and Microsoft Outlook. With his visibility into the proxy network, Bill can see whether or not an authentication attempt succeeds based on the network response from the email provider (e.g. mail server responds “OK” = successful access). 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.”

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. “These guys want that hard digital asset — the cash that is sitting there in your inbox,” Bill said. “You literally just pull cash out of peoples’ inboxes, and then you have all these secondary markets where you can sell this stuff.” 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. "

Quote : " “To me, this is an important story because for years people have been like, yeah we know email isn’t very secure, but this generic statement doesn’t have any teeth to it,” Bill said. “I don’t feel like anyone has been able to call attention to the numbers that show why email is so insecure.” Bill says that in general companies have a great many more tools available for securing and analyzing employee email traffic when that access is funneled through a Web page or VPN, versus when that access happens via IMAP. “It’s just more difficult to get through the Web interface because on a website you have a plethora of advanced authentication controls at your fingertips, including things like device fingerprinting, scanning for http header anomalies, and so on,” Bill said. “But what are the detection signatures you have available for detecting malicious logins via IMAP?” Microsoft declined to comment specifically on Bill’s research, but said customers can block the overwhelming majority of account takeover efforts by enabling multi-factor authentication. "

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