If you start getting an email bombed out of nowhere, being signed up for hundreds of newsletters or other email notifications, take a quick look at your credit card statements for any unknown purchases. Email bombs are often used by card thieves to hide legitimate purchase notifcation email from retailers when they use your stolen creds.
Another reason to actually get your credit card statement via snail-mail.
I understand it is wasteful, but I go on an evening walk and pick up the mail.
The effort for me to pick up the mail and read my credit card statement is actually quite nice.
It doesn't require you to sign in, and search my house for my phone or my YubiKey, it doesn't prompt me for other credit card offers, doesn't require me to download a PDF reader.
Better yet, setup transaction alerts on all your credit cards, and use a budgeting app like Monarch/YNAB to review all your household transactions each month or receive weekly email summaries.
Brian Krebs is a saint for being the perennial punching bag and target of cybercriminals but continuing to publish important information independently.
This attack is called email amplification. Any open form that triggers email sending is vulnerable. Fortunately these bots are pretty basic in my experience, putting a captcha (or anything unexpected) in front is enough to stop these bots.
This spam campaign drove me nuts! I received so many of these emails from so many random companies.
The key takeaway is to always have a email verification loop (or something stronger like phone verification) when using an anonymous user feature. You need to prove you own an email address before you use it.
Yeah I got enough of these from discord, that I emailed their abuse@ and put in a support ticket, but they ignored me. Nice to have it confirmed. I ended up doing a password rotation on the off chance it was me.
Unless I missed it, the article doesn’t explain how this works. It seems like the spammer sends an email to support@somecompany.com but spoofs the From address to be the target of the spam. The Zendesk ticket system then sends the auto reply to the spoofed From address
This doesn't surprise me since Zendesk uses the same DKIM key for all customers. I have multiple domains that I support and they all point to the same CNAME record.
Another fun Zendesk “feature,” that, to my knowledge, has never been fixed is if you CC it on a thread with any other email address that auto-replies, it will get stuck in a loop and ping-pong emails back and forth until the mailbox fills up.