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Security The Almighty Buck

Gift Card Gang Extracts Cash From 100K Inboxes Daily (krebsonsecurity.com) 10

Cybercrime and computer security reporter Brian Krebs tells 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. From the report: 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.

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Gift Card Gang Extracts Cash From 100K Inboxes Daily

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  • A fool and his gift card balance are soon parted.
    • How do you use 2FA with IMAP when you have multiple email accounts linked?

      • Never mind. I checked, and IMAP is disabled in Gmail for me. I did it so long ago that I forgot Google has a special process to use the 2FA to authenticate a single device for use with POP/SMTP.

        • Yeah, Gmail users don't need to worry about this. They're targeting providers that are not secure by default.
  • by jjaa ( 2041170 ) on Friday September 03, 2021 @01:47AM (#61758787)
    It's written as if someone tries to purposefully make IMAP look bad (and desktop email clients with it)... then what instead? Make everyone use webmail because it's that much betterer? xD
    • Well... IMAP is bad for security, relative to the alternatives (web authentication and Exchange). I'm not saying the protocol is a bad way to get mail, but it simply was made so long ago that it doesn't support many things that we take for granted in a secure system nowadays, like support for MFA.

      I'd love to see IMAP get a widely supported extension to allow for better security, so that Microsoft can stop being able to claim the majority of enterprise customers partly via their (true) claim of better securi

      • by Anonymous Coward

        You can use OAuth2 with IMAP. This is how I access exchange with Thunderbird.

    • Unless I misread this, this only hits people running IMAP in cleartext. In other words, idiots. You can run encrypted IMAPS. Dovecot is a nice secure IMAPS server.

  • Sheesh - it's Jim. Bill's the one who did the dual elliptic curve hash exploits. You'd think a world-class security researcher like Brian Krebs would anonymize properly.
  • It's an interesting story, but it still seems to be about weak/stolen usernames/passwords, not "SMTP, POP or IMAP are bad", etc.

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