The Codefinger Ransomware Attack: Wake-Up Call for Cloud Security

Picture this: It’s a regular Tuesday. Your team is rolling out updates, pushing code, and everything in your AWS environment looks calm and under control.

Then you get an alert that your Amazon S3 buckets have been encrypted.

Not by malware. Not from an infected laptop. But by someone using AWS’s features—SSE-C encryption—against you.

This isn’t fiction.

It happened very recently in the 2025 Codefinger ransomware attack.

This breach exposed a hard truth: even legitimate cloud-native features can be exploited if security isn’t built into the architecture. Security isn’t just about having the right tools—it’s about thoughtfully designing your cloud environment to prevent misuse.

In this newsletter, we’re exploring what it means to build securely in AWS.

We'll cover:

• What went wrong with Codefinger: When native services are misused due to weak configurations

• How AWS helps you protect yourself: Identity boundaries, encryption strategies, and monitoring

• Security best practices: Principle of least privilege, managed key services, secure access policies

• Why SSE-C is risky: When to use SSE-KMS or SSE-S3 instead

• Real-world strategies: Setting up detective controls, centralized logging, and compliance automation

Let’s start!