Tutorial / Cram Notes
When managing compute workloads on AWS, one crucial aspect is ensuring that secrets and credentials are passed securely to prevent unauthorized access and potential breaches. AWS provides various methods to manage, distribute, and rotate secrets securely. Here we will explore some of these methods and services that you should be aware of when preparing for the AWS Certified Security – Specialty (SCS-C02) Exam.
AWS Identity and Access Management (IAM) Roles
Using IAM roles is the recommended way to provide credentials to applications running on AWS services like EC2, Lambda, or ECS.
For example, assign an IAM role to an EC2 instance:
{
“Version”: “2012-10-17”,
“Statement”: [
{
“Effect”: “Allow”,
“Action”: “s3:GetObject”,
“Resource”: “arn:aws:s3:::example_bucket/*”
}
]
}
The EC2 instance can now access objects in example_bucket without storing any access keys or secrets.
Environments and Launch Configurations
For ECS or Elastic Beanstalk, the environment’s launch configuration can include environment variables that are accessible to the application.
For sensitive information, use environment variables with care, and avoid logging them.
AWS Secrets Manager
Secrets Manager is a service that helps you protect access to your applications, services, and IT resources without the upfront investment and on-going maintenance costs of operating your own infrastructure.
| Feature | AWS Secrets Manager |
|---|---|
| Secret Rotation | Supported |
| Encryption at Rest | Automatically encrypted |
| Fine-Grained Access Control | IAM Policies |
| Direct Integration with AWS Services | Yes |
| Auditing with AWS CloudTrail | Supported |
Using AWS Secrets Manager, you can inject secrets directly into your application with no code changes:
- Store secret:
aws secretsmanager create-secret –name MySecret –secret-string ‘{“username”:”exampleuser”,”password”:”examplepassword”}’
- Retrieve secret in your application code:
import boto3
import json
client = boto3.client(‘secretsmanager’)
response = client.get_secret_value(SecretId=’MySecret’)
secret = json.loads(response[‘SecretString’])
username = secret[‘username’]
password = secret[‘password’]
AWS Systems Manager Parameter Store
The Parameter Store provides secure, hierarchical storage for configuration data and secrets. Like Secrets Manager, it offers fine-grained access control and full auditability with AWS CloudTrail.
| Feature | AWS Systems Manager Parameter Store |
|---|---|
| Secret Rotation | Manual with Automation Documents |
| Encryption at Rest | Optional, via KMS keys |
| Fine-Grained Access Control | IAM Policies |
| Direct Integration with AWS Services | Yes |
| Auditing with AWS CloudTrail | Supported |
Example of storing a secret in the Parameter Store:
aws ssm put-parameter –name “/MyApp/database/password” –type “SecureString” –value “mypassword” –overwrite
And to retrieve it in your application:
import boto3
ssm = boto3.client(‘ssm’)
parameter = ssm.get_parameter(Name=’/MyApp/database/password’, WithDecryption=True)
password = parameter[‘Parameter’][‘Value’]
AWS Key Management Service (KMS)
AWS KMS can be used in conjunction with the services mentioned above to encrypt secrets at rest. KMS is integrated with IAM for access control, and you can use it to create and control the cryptographic keys used for encryption, ensuring that only authorized personnel can use them.
Best Practices for Passing Secrets and Credentials
- Never embed credentials and secrets in code. Always retrieve them dynamically and inject them at runtime.
- Manage permissions strictly using the principle of least privilege. Grant only the necessary access to services and resources.
- Practice key rotation frequently to minimize risks associated with compromised credentials.
- Use AWS provided mechanisms for secret management, avoiding reliance on less secure, custom solutions.
- Regularly audit access and usage of secrets to detect anomalies and unauthorized access.
- Implement logging and monitoring via AWS CloudTrail and Amazon CloudWatch to get a comprehensive view of actions performed on your secrets.
In conclusion, AWS provides multiple services and practices that can be used for managing and injecting secrets and credentials into compute workloads. Understanding and skilfully applying these methods will significantly contribute to the security of your resources on AWS, and is a critical domain covered by the AWS Certified Security – Specialty (SCS-C02) Exam.
Practice Test with Explanation
True or False: It is acceptable to pass secrets and credentials to compute workloads as environment variables without any encryption.
- True
- False
Answer: False
Explanation: Passing secrets and credentials as unencrypted environment variables is insecure because environment variables can often be logged or accessed by unauthorized users or processes.
Which AWS service allows you to securely manage and retrieve secrets?
- AWS KMS
- AWS Secrets Manager
- AWS IAM
- Amazon S3
Answer: AWS Secrets Manager
Explanation: AWS Secrets Manager is designed specifically for managing, retrieving, and rotating secrets used by applications and services.
True or False: IAM roles with appropriate permissions can be used to securely provide compute workloads with the necessary credentials.
- True
- False
Answer: True
Explanation: IAM roles can be used to securely assign permissions to compute instances, ensuring that credentials are not directly passed or hard-coded.
In the context of EC2 instances, what feature can be used to pass user data securely on launch for initial configuration?
- Security Groups
- EBS Volume Encryption
- EC2 Instance Metadata Service
- Amazon S3 Pre-signed URLs
Answer: EC2 Instance Metadata Service
Explanation: The EC2 Instance Metadata Service can be used by instances to retrieve user data securely for initial configuration without exposing sensitive information.
True or False: AWS Parameter Store is an appropriate service to manage and store plaintext configuration data, but not secrets or credentials.
- True
- False
Answer: False
Explanation: AWS Systems Manager Parameter Store can be used to store not only configuration data but also secrets, which can be encrypted with KMS keys.
Which technique should NOT be used to manage database credentials in AWS?
- Using IAM Database Authentication
- Rotating credentials with AWS Secrets Manager
- Hardcoding credentials in the application code
- Storing encrypted credentials in Parameter Store
Answer: Hardcoding credentials in the application code
Explanation: Hardcoding credentials in application code is a security risk because it exposes credentials in source control and does not allow for easy rotation or management of credentials.
When using AWS KMS, what ensures that only designated services or users can decrypt secrets?
- Key policies
- Security Groups
- NACLs
- IAM User Policies
Answer: Key policies
Explanation: Key policies in AWS KMS define the permissions for which users or services can use the KMS key to encrypt and decrypt data.
True or False: AWS Lambda functions can use environment variables encrypted with KMS keys to securely handle secrets and credentials.
- True
- False
Answer: True
Explanation: AWS Lambda supports environment variable encryption using KMS keys, which allows secrets and credentials to be securely passed to Lambda functions.
Which feature provided by AWS guarantees both encryption in transit and encryption at rest for secrets?
- Instance Store encryption
- SSL/TLS Certificates
- AWS Secrets Manager with KMS encryption
- EBS Volume Encryption
Answer: AWS Secrets Manager with KMS encryption
Explanation: AWS Secrets Manager automatically encrypts secrets at rest using KMS keys and supports encryption in transit using HTTPS/TLS.
True or False: You can use IAM Access Analyzer to identify resources that allow sharing your secrets with external entities.
- True
- False
Answer: True
Explanation: IAM Access Analyzer helps identify resources in your AWS environment that are shared with an external entity, which can include objects with your secrets.
Which of the following services is NOT directly involved in the secure transmission of secrets to compute instances?
- AWS Secrets Manager
- AWS KMS
- Amazon CloudFront
- AWS Systems Manager Parameter Store
Answer: Amazon CloudFront
Explanation: Amazon CloudFront is primarily a content delivery network and is not directly involved in secret management or the secure transmission of secrets to compute instances.
True or False: AWS recommends the use of temporary security credentials using AWS STS (Security Token Service) for greater security when passing credentials.
- True
- False
Answer: True
Explanation: AWS STS provides temporary security credentials that automatically expire after a short duration, reducing the risk of long-term credential compromise.
Interview Questions
What AWS service would you use to securely store and manage secrets and application credentials?
AWS Secrets Manager is the service specifically designed to securely store, manage, and retrieve secrets, such as database credentials, API keys, and other sensitive information. It helps to control access to secrets using fine-grained permissions and automatically rotates secrets according to the defined schedule.
How can you pass secrets to an AWS Lambda function securely?
Secrets should be retrieved from the AWS Secrets Manager or AWS Systems Manager Parameter Store by the Lambda function at runtime. For additional security, AWS Lambda’s execution role should have the necessary permissions to access these services, ensuring that access to secrets is controlled by IAM policies.
In an EC2 environment, how can you securely provide EC2 instances with the required credentials to access other AWS services?
The best practice is to assign an IAM Role to the EC2 instance, which automatically provides temporary credentials that the EC2 instance can use to make AWS API calls. This removes the need to pass static credentials and manage their rotation or security.
What mechanisms are available in AWS to rotate secrets, and why is this practice important?
AWS Secrets Manager provides native functionality to rotate secrets automatically. This practice is crucial as it reduces the risk associated with stolen or compromised credentials by ensuring that they are valid only for a short period.
What practices should you avoid when passing secrets to compute workloads on AWS?
You should avoid embedding secrets and credentials directly in the source code, using environment variables for sensitive information, or storing them in a plain text file on the compute instance. These practices could lead to unintentional secret exposure and a security breach.
How can you ensure that secrets are encrypted in transit when being passed to compute workloads?
To ensure that secrets are encrypted in transit, you should use HTTPS (TLS/SSL) when retrieving secrets from services such as AWS Secrets Manager or AWS Systems Manager Parameter Store. Additionally, access to these services should be over a private network, such as a VPC, whenever possible.
How does AWS Systems Manager Parameter Store help in managing secrets?
AWS Systems Manager Parameter Store provides secure, hierarchical storage for configuration data management and secrets management. It can store values as plain text or encrypted data, and it integrates with IAM for access control. This service can also be used to separate secret usage from code.
What is the significance of using AWS KMS with AWS Secrets Manager?
AWS KMS (Key Management Service) is integrated with AWS Secrets Manager to encrypt the secret at rest with encryption keys managed by KMS. This combination ensures that the secret material is encrypted using a strong encryption mechanism and that the key management is also centralized and secure.
How would you control access to secrets in AWS for different environments (e.g., development, staging, production)?
You should use IAM roles and policies to grant access to secrets based on the principle of least privilege. Separate secrets for each environment can be created, and only relevant roles should have the permissions to access those secrets. Additionally, resource-level permissions can be defined for fine-grained access control.
Can you describe a strategy to audit access to secrets in AWS?
AWS Secrets Manager integrates with AWS CloudTrail to log all actions taken on secrets. You can use CloudTrail to audit who accessed which secret, from what IP address, and at what time. This enables you to detect unauthorized access or track down the cause of a potential leak or misuse of credentials.
What is the benefit of using AWS IAM roles for tasks instead of using static credentials for containers in Amazon ECS?
By using IAM roles for tasks in Amazon ECS, you can assign permissions to the containers in the tasks directly, without the need to manage static credentials. These roles provide temporary credentials automatically to the container, ensuring the credentials are rotated frequently and reducing the risk of credential leaks.
How would you securely manage database credentials for an AWS RDS instance accessed by multiple compute instances?
Securely managing database credentials for RDS instances involves storing the credentials in AWS Secrets Manager. IAM roles can be assigned to the compute instances that need access, which have permissions to retrieve the credentials from Secrets Manager. Additionally, enable secret rotation to change database passwords automatically at defined intervals.
Great blog post! Learned a lot about AWS security best practices.
Thanks for the insights on passing secrets securely in AWS. Very helpful.
Could you explain more about AWS Secrets Manager vs Parameter Store?
Really informative! I’ll definitely use these tips in my project.
How do IAM roles fit into the secure passing of secrets?
Fantastic overview on AWS security basics.
I had difficulties setting up Secrets Manager. Any suggestions?
Very useful tips, thanks!