What steps should a cloud administrator take to protect against unintended user actions when uploading images through a mobile application?

The correct approach to protect against unintended user actions when uploading images through a mobile application is to upload the images to Amazon S3 by using presigned URLs in conjunction with strict bucket policies.

Using presigned URLs ensures that only authorized users can upload files to the S3 bucket, as these URLs are generated with specific permissions and time limits. This means that users can only perform specific actions (like uploading) within a predefined window of time and on specific resources, minimizing the risk of unauthorized access or actions.

Furthermore, applying strict bucket policies adds an additional layer of security by defining who can access the resources in the bucket and under what conditions. These policies can restrict access to the bucket so that only those who need it can interact with it, preventing unauthorized actions that could lead to data loss or exposure.

Together, presigned URLs and strict bucket policies create a robust security framework that mitigates the risks associated with direct uploads, thereby greatly enhancing the overall security posture of the application.