AWS security follows the shared security model where the user is as much responsible as Amazon. Since Amazon is a public cloud it is bound to be targeted by hackers. If an organization is planning to host their application on AWS EC2, they should perform the below mentioned security checks as a measure to find any security weakness/data leaks:
Perform penetration testing as performed by attackers to find any vulnerability. The organization must take an approval from AWS before performing penetration testing Perform hardening testing to find if there are any unnecessary ports open Perform SQL injection to find any DB security issues The code memory checks are generally useful when the organization wants to improve the application performance.
http://aws.amazon.com/security/penetration-testing/

The user can configure the AutoScaling group to automatically scale up and then scale down based on the specified conditions. To configure this, the user must setup policies which will get triggered by the CloudWatch alarms.
http://docs.aws.amazon.com/AutoScaling/latest/DeveloperGuide/as-scale-based-on-demand.html