Magento Checkout Malware Cleanup

My Magento store was recently hit by malware and, ever since, the checkout page crawls or throws random errors before an order can be placed. I already attempted a couple of fixes—including cache flushes, rolling back templates, and a basic malware scan—but the problem keeps returning, so I’m looking for a deeper, permanent solution.

Here’s what I need from you:

• Pinpoint the malicious code or injected files that are slowing the page and breaking the checkout flow.
• Remove / neutralize the infection without disrupting core Magento functionality, custom modules, or theme overrides.
• Verify that the checkout loads fast, processes payments to completion, and displays no PHP or JavaScript errors.
• Provide a short report of what was cleaned and any hardening steps applied (e.g., patch levels updated, file-permission tweaks, WAF rules).
• Recommend an ongoing prevention strategy so the attack doesn’t recur.

Acceptance is straightforward: a clean security scan, normal page-load times, and at least five successful test orders running end-to-end.

If you have solid experience with Magento malware removal and performance tuning, let’s get started right away.