Correct Answer : D.
Applications deployed on Amazon EC2 instance can be provided security credentials using AWS STS, allowing short-term limited period credentials.
With this, there is no need to save credentials in the Amazon EC2 instance.
Options A & C are incorrect as the IAM users & IAM group can create authentication & manage access for users accessing AWS services.
Saving these credentials on EC2 for applications while accessing other AWS resources is against security guidelines.
Option B is incorrect as Amazon Cognito helps to provide user access control for mobile & web apps.
For more information on use cases for AWS STS, refer to the following URL:
https://docs.aws.amazon.com/IAM/latest/UserGuide/id_credentials_temp.html
The correct answer is D. AWS STS.
AWS STS (Security Token Service) is a web service that enables you to request temporary, limited-privilege credentials for AWS services. These temporary credentials can be used to access AWS resources from applications running on Amazon EC2 instances with an IAM role configured.
When a request for temporary credentials is made, STS verifies the identity of the requestor and returns a set of temporary security credentials, including an access key ID, a secret access key, and a security token. The temporary security credentials have limited permissions and a short lifespan, typically one hour, after which they expire and can no longer be used.
The other options are not correct because:
A. AWS IAM user: An IAM user is a permanent identity that you create in AWS to represent a person or application that interacts with AWS services. IAM users have long-term credentials that consist of an access key ID and a secret access key, which do not provide temporary access.
B. Amazon Cognito: Amazon Cognito is a user authentication and authorization service. It does not provide temporary credentials for accessing other AWS resources.
C. AWS IAM groups: An IAM group is a collection of IAM users. Like IAM users, IAM groups have long-term credentials that do not provide temporary access.
