IMDSv2 (Instance Metadata Service Version 2) is a more secure iteration of the Instance Metadata Service provided by Amazon EC2. It enables EC2 instances to access their own metadata, configurations, and temporary security credentials. Here’s a breakdown of IMDSv2 and its primary use cases:

Overview of IMDSv2:

• Security Enhancements: IMDSv2 introduces a session-oriented approach that requires a secret token, enhancing security over the previous version (IMDSv1), which allowed metadata access via a simple HTTP request.
• Session Tokens: Tokens must be retrieved with a PUT request and then used with subsequent GET requests. These tokens are short-lived, providing an additional layer of security against potential attacks, such as SSRF (Server Side Request Forgery).
• Enforced HTTP Method Checking: It ensures that the correct HTTP methods are used when calling the service (e.g., PUT to fetch the token and GET to use the token), which helps prevent misuse.

Use Cases of IMDSv2:

1. Security Credential Distribution: It provides temporary AWS credentials to applications running on EC2 instances, enabling them to securely access other AWS services without hard-coding credentials.
2. Configuration Management: Instances can retrieve data about themselves, such as instance IDs, instance types, and network settings, which can be used for dynamic configuration and management.
3. Bootstrapping Applications: Metadata can be used to pass user data scripts to instances upon launch, facilitating automated setup processes.
4. Audit and Logging: By accessing instance metadata, applications can log and audit behavior based on the identity and characteristics of the EC2 instance.
5. Dynamic Scaling and Maintenance: IMDSv2 can be utilized to manage scaling actions and maintenance tasks by providing information that helps in decision making regarding when to scale in or out.

Migration from IMDSv1 to IMDSv2:

Organizations are encouraged to migrate from IMDSv1 to IMDSv2 to benefit from its enhanced security features. This typically involves updating the code that interacts with the metadata service to handle token retrieval and management.

IMDSv2 plays a critical role in ensuring that applications running on EC2 instances can dynamically and securely access configuration data and credentials, which is essential for maintaining the robustness and flexibility of cloud environments

How to enable IMDSv2 in multiple EC2 instance AWS: Shell Script

List all the ec2 instance based on tags and using SSM How to enable IMDSv2 in multiple existing EC2 instance AWS