I've just been notified of a remote code execution vulnerability and an xss vulnerability on a site that I run. I've fixed the responsible code, but I'm wondering what steps should be taken afterwards to:
- Ensure the server is secure
- Ensure no data was compromised
- Ensure no malicious files were uploaded.
The remote code execution vulnerability was particularly bad and allowed any PHP code to be run on the server and output displayed to the user.
The app is hosted on Amazon Lightsail. Would it be helpful to redeploy on a new instance?