Emotet: What the hell is it?

If you are into malware/malware analysis, I bet you come across this particular one more than anything else. The thing is, most people don’t necessarily know what Emotet actually is. Or at least the details, as to what type of malware it is and what it actually does.

Some of us in the industry have been known to get a bit riled up occasionally when this malware is being publicly discussed, in regards to the technical details of it.

So I’m going to put down a few thoughts (and I anticipate backlash from those who’ve spent more time on this than me :) for obvious reasons) and hopefully that’ll help us keep the emphasis on the more important tasks (fighting malware).

Emotet is a downloader (I can literally feel temperatures rising in the cyberverse already) — ie. it executes on the victim machine and then connects back to a server somewhere in the cloud (literally) and downloads another malicious executable and then executes it. At this point, its job is pretty much done. Seriously, that’s it for old mate Emotet — from this point on, things become murky.

Now….

Traditionally, or historically, whatever you prefer, Emotet has been downloading a malicious payload that goes by the name of Feodo. It also goes by several other names (eg. Geodo) but let’s not get into that just yet. Feodo is what you could call a ‘final’ payload, which executes on the victim machine and then does bad things to it. Let’s leave it there.

Now what has happened in the past is that we have been calling the entire package as ‘Emotet’ — so basically, the downloader and the final payload. Which is ok… It has mostly been the case, so it doesn’t really matters that much if you only really care about defending against the entire malicious package.

The only problem is, what happens when Emotet starts downloading a different malware for final execution? For example, it has very recently been downloading Trickbot. That changes everything. Or the very least, half of the Emotet story. I’ll let you decide at this point what to do with this love triangle when one the main characters decides to ‘diversify’.

Hope I’ve made things clear. Or not.

Basically, it’s a malware that downloads and executes more malware and we’ve been calling the whole package by the same name. For the most part it has worked, it’s not the end of the world.

Also, the downloader bit is the macro-based VBS code, the final payload is a PE.