ESP being phished is a Black Friday cataclysm


There is currently a phishing attack against a major ESP. The mail came through what I presume was a compromised account hosted at one of the providers. It’s just as possible this was a domain set up for the sole purpose of phishing, though.

Icon of an eye looking around

The underlying attack is pretty good. They took the ESP compliance notification email and changed a couple of the links to point to their phishing page (which is down now). I’m pretty sure a message “your account has been limited due to poor reputation” caused a whole lot of folks to freak out and click the links.

If it were me coordinating the attack, I’d be quietly logging into the compromised accounts over the next 10 days and creating new API keys. I’d set up my spam cannons to use those API keys and then wait for Black Friday. A single button and I can send out … millions and millions of authenticated emails through hundreds of accounts with solid reputations.

Steve and I were talking about this last night and were discussing tracking logins, 2FA and other ways the ESP could mitigate the problem and protect their users. It wasn’t until I woke up this morning that I remembered that the ESP has a full API. Yeah, that makes it even harder. Sure, the spammers need to log in and create new API keys. But individual logins that simply create API keys are harder to detect than a log in that doesn’t do anything but create a key.

This is not something the ESP can easily mitigate in 10 days. They will have had to have infrastructure in place to track creation of API keys and confirm these keys are being used by their customer. I know this ESP and I am hopeful that their security folks have thought about this attack vector.

If you are a Sendgrid customer, it may be worthwhile to revisit your infrastructure today. Identify what needs API keys and regenerate them. Then, nuke all the keys in your account. Change all your passwords. Lock down your account.

I feel for both the ESP and their customers. This was a carefully planned attack. I have zero doubt this is in preparation for sending out a massive spam campaign from the ESP at the height of the holiday email season. Don’t assume your account is safe. Make sure it is.

Otherwise, you may find more than the normal level of delivery problems for your holiday mail.

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By laura

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