Using OMI on Microsoft Azure? Here’s an update you need to read

If you have never heard of OMI, you are not alone! It’s an open-source project run by Microsoft that’s not that well-known. However (worryingly in this case), it’s one of the most widespread programs installed on the Azure Cloud virtual machines.

The issue is that OMI has not been updated automatically, as one would expect, so the sysadmins responsible for these servers could unknowingly leave an outdated version of OMI exposed to the wild. As of today (September 17, 2021), Microsoft has started updating impacted Azure services. However,  thousands of servers remain exposed with an easily exploited security vulnerability.

How long has this RCE through OMI been exploited in the wild?

We are not certain, but our researchers see Mirai malware variants actively exploiting this vulnerability on the exposed Azure servers. Here’s a great example. This means that, like so many other things, Mirai variants are migrating to the cloud. Our eXploits Blocklist (eXBL) dataset includes Mirai sightings, so our researchers will keep you posted if the situation changes dramatically.

What to do if you have OMI installed

If you are a Microsoft Azure user –  DON’T PANIC! Grab a coffee, keep reading and put a plan of action together.

All OMI versions below v1.6.8-1 are vulnerable. We urge you to check your OMI version, and if it is at risk, have your security team read and implement this documentation from Microsoft as soon as possible.

Please consider that your servers may have already been exposed to an attack! If your servers are running OMI, you should consider them insecure and take the corrective actions that your IT team suggests.

What if your servers have been compromised?

If your machines have been exploited, are part of a botnet, or are misbehaving in other ways, it may be time to consider Spamhaus’ Intelligence API (SIA). This API enables you to promptly detect if you have an issue with one (or more) of your IPs, i.e. if it’s listed on our eXploits blocklist or CSS blocklist. SIA serves up enriched data relating to IPs that our research team observes to exhibit signs of compromise or IPs emitting spam.

Remember reputation matters

The word “compromise” immediately brings to mind ransomware horror stories, given the recent proliferation of high-profile attacks that have been covered in the media. But, you must remember the importance of the reputation of your IP space.

If the IP space you use is seen to be a cesspit, be it no fault of your own, then trouble will follow, including issues with sending legitimate emails.

The data provided through SIA allows you to view both current and historical IP listings, arming you with the knowledge of how much compromise has happened across your network today and what has happened historically. This provides you with a good indicator of how good or bad your IP reputation may be.

Testing the waters

If you’d like to experiment with SIA data and how you can utilize it, you can sign-up for a free Developer License, which provides you with a limited number of queries per month at no cost.

Finished your coffee?

It’s time to start to put that plan into action. Good-luck! We hope you don’t find any signs of compromise.