Securing Temporary Credentials in AWS: What You Should Be Doing But Probably Aren’t

#aws #security #devsecops #iam

🔐 Temporary credentials in AWS are powerful—but also widely misunderstood.

They allow developers and systems to access AWS resources without relying on long-lived access keys. But just because they expire doesn’t mean they’re safe by default.

In this post, I break down:

✅ When and why to use temporary credentials
🧱 Where things go wrong (over-permissive roles, lazy session durations…)
🔒 Best practices for keeping temp creds secure
🧠 Advanced use cases like federation and IAM Roles Anywhere

🚧 Where People Go Wrong

I’ve seen real-world setups where:

Temp credentials lasted 12 hours
Were used with AdministratorAccess
In CI/CD pipelines with no monitoring

That defeats the whole point of ephemeral access.

🛡️ What You Should Be Doing

🔸 Use least privilege roles

Scope your roles tightly and use IAM condition keys like aws:SourceIp.

🔸 Shorten session durations

15–30 minutes is more than enough for most automation tasks.

🔸 Log STS usage with CloudTrail

Every AssumeRole or GetSessionToken should be traceable and alertable.

🔸 Require MFA where appropriate

Especially for sensitive role assumptions—break-glass or prod access.

🔸 Automate responsibly

Don’t reuse temporary creds or store them insecurely in config files. Use the SDKs properly.

🧠 Bonus: IAM Roles Anywhere

For non-AWS workloads (like on-prem apps), IAM Roles Anywhere lets you issue short-lived AWS credentials using signed certificates. It's a powerful addition for hybrid setups, but comes with its own set of guardrails.