AWS Lambda: Is it secure to store data on AWS Lambda local Disk?

Question

I have following basic security related questions regarding AWS Lambda service:

1. Where does AWS Lambda store data if for example I try to store data on local disk?
2. Is is possible to encrypt the data on Lambda?

Thanks

Answer 1

One important sidenote to the /tmp of Lambda functions is that the Lambda function containers are re-used and scratch space is not always erased. If an invocation uses a container that was spun up because of a previous invocation (this happens if you execute a few Lambda function in quick succession), the scratch space is shared.

This screwed up a functionality for me once.

Answer 2

I store temporary data in my lambda function, never had any issue.

• Store your data in /tmp, you may not have access to other dirs
• The temporary data - as the name indicates - is available only for that invocation of lambda
• If the data is sensitive, encrypt it (if the encryption libraries are not provided by default for that language, make sure you package the library)