Hello,
This is a good but very deep question. First let me give you this Power Platform security FAQs - Power Platform | Microsoft Learn
Now there are unfortunately many factors when you are talking about Power Apps / Power Platform.
1. Are you going Canvas or Model driven apps
2. Are you building any components / pcf
3. Are you building plugins (real code), workflows and so on
4. What roles are you using, what groups, are you linking to AAD from Dataverse and again a large list.
5. Are you using 3rd party connectors
6. Are you integrating with Data Lake / Other / SQL etc / OnPrem / Gateways / Functions / Web Services etc etc
7. What is your total eco system looking like
... and a long list 😞
To my knowledge there are some possible SAST / DAST but I am not aware of any specific Microsoft ones, and I don't know which ones would be best to recommend.
Cheers
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Thank You
Michael Gernaey MCT | MCSE | Ex-Microsoft
https://gernaeysoftware.com
LinkedIn: https://www.linkedin.com/in/michaelgernaey