True or False? By default, all data stored in S3 is viewable by the public.

The assertion is false because by default, all data stored in Amazon S3 (Simple Storage Service) buckets is not publicly viewable. When a new bucket is created, it is private, meaning that only the AWS account owner has access to the data stored within that bucket.

To make S3 data accessible to the public, specific permissions must be granted through bucket policies or Access Control Lists (ACLs). Users have the ability to configure the level of access, ensuring that sensitive data can remain protected and only shared appropriately. This design is intentional to help maintain data security and privacy, as assuming that all data is public could lead to unintended exposure and vulnerabilities.

Thus, the statement is indeed false, as public access is not granted by default, safeguarding user data from unauthorized access.