31 Oct 2018

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Check: ECR

JASP Checks: ECR

As we build JASP, we’re brainstorming and learning about security (so far, primarily in AWS).  This is the first in a series of “Check Deep Dive” posts that talk about things we are checking for in JASP.  It seems like an interesting area to share information.  Incidentally, we’re also going to post more meta posts about the Jemurai and JASP journey.

The first simple check we’ll talk about is around AWS ECR or Elastic Container Registry.  If you are using Docker containers and managing their lifecycle in AWS, you may be using ECR.  You may also be using Docker Hub or other container registries.  This check really demonstrates some of the power of checking security things through an API.  By using the ECR API, we can know some things about the containers hosted in AWS ECR just by asking, the way we do about anything else.

Specifically, we can know the age of the image, any tags and when it was last pushed.  We can easily iterate across regions and find older tagged images.  The idea for most clients we work with is that they want their docker images to be recent.  Older images suggest that they are not patching or updating a given container.  Especially older tagged images are likely places that need to be updated.

Essentially, JASP will check each region for images that are old and alert you to that.

Now, AWS allows you to set lifecycle policies for ECR.  This is a really cool feature.  This can allow you to expire and track this right in AWS.  We totally recommend doing this.  That said, we only have one client that lives this hardcore and actually automatically removes any expired images after every 30 days.  In that case, if they haven’t built an updated image within 30 days, too bad for them.  They’re in it to win it.  And frankly, they are walking the walk there.

On a side note, we have another client that is using Docker heavily and claimed to be patching every 30 days because they pushed new Docker images every 30 days.  When we dove a layer deeper though, we realized that they were hard setting to a very old version of Alpine Linux, which removed many of the benefits of updating frequently.  In other words, they were updating the layer they were building but not the layers they were building on.  To be crystal clear, this “check” won’t identify this issue - you’ll want to look at your dependencies with a tool like dive to do that.

References

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