Securing Terraform and You Part 2 -- Trivy by AquaSecurity

9/20: The open source version of Terraform is now OpenTofu 

 Part one is over here.

This comes as the 3rd tool in a long line of tools I am using to make Terraform (OpenTofu) code consistent. I went back to the Styra Academy courses for OPA Policy Writing. I am a very "Just show me the general idea, and I can probably figure it out", and I am reasonable enough to say that it didn't work this time, and I had to take the slow road.

Good start; Trivy told us where it installed;

trivy info installed /usr/local/bin/trivy

/Users/morganza/Library/Caches/trivy

the homebrew package had an outdated version, so I had to install v. 0.40.0 myself and link it to the previously installed 0.18.0 I believe -- See the GitHub discussion here.

We are now back to rego, but fortunately, Trivy works as intended when you run it locally with the following command;

trivy conf --policy . --namespaces morganza .

There was an odd combination of YAML with a bit of rego involved for tfsec -- can we do that here?

It got to the point where I had to dig around in the config files for an example. It's quite organized, and every (Department?) Trivy scans has it's own folder, most empty.

The only policies in place (I could not find the secret YAML file) are about Remote Desktop Services. 

the metadata is in JSON, and is commented out, though it does provide a rego example! 

https://blog.ediri.io/how-to-write-custom-policies-for-trivy

I had to go back and forth between the rego GitHub and the Trivy GitHub; People know either one or the other, not both.

If you need to set up some rules once and edit them very rarely, using rego will be great. If you plan to use it a lot, you will get a lot of practice and be good at it. 

As of this posting, I still haven't figured it out. The code looks right to me, to others. Good news, on August 11th, the problem was solved [Click here]!

...

OPA/rego may be easy to use and learn, but I haven't found the solution -- or someone who can walk me through to it -- yet. If Trivy allowed us to write policies in more popular languages, it would be a good start. 

Open Policy Agent / rego may be flexible, but the learning curve is steep and not accessible to quickly getting up to speed.

To conceptualize or test something, an employer would want a quick solution.