Sunday, September 22, 2024
Monday, September 9, 2024
AWS - Access Key ID vs Secret Access Key
https://chatgpt.com/share/48336e83-2376-439d-acd3-79ea2fe5b7d6
The term "Access Key ID" is not called "Secret Access Key ID" because the Access Key ID itself is not considered a secret. Here's the reasoning:
Access Key ID: This is a public identifier for the credential. It is used to identify the user or service that is making requests to AWS. The Access Key ID is not secret, and it can be shared (for example, in logs) without compromising the security of your AWS resources.
Secret Access Key: This is a private component that must be kept confidential. It works like a password and is used in combination with the Access Key ID to sign API requests. Anyone with access to both the Secret Access Key and Access Key ID can make authorized API requests, so the Secret Access Key must be kept secret.
Session Token: In the case of temporary credentials from AWS STS (Security Token Service), the Session Token is also a secret and is used in conjunction with the Access Key ID and Secret Access Key to authenticate API requests for the session's duration.
Thus, the "Access Key ID" is the public-facing part that identifies the key, while the "Secret Access Key" and "Session Token" are sensitive, secret components. That's why the "Access Key ID" is named as it is—it's meant to be distinguishable from the actual secret that provides authentication.
AWS - Security Token Service (STS)
AWS STS (AWS Security Token Service) is a service that allows you to request temporary, limited-privilege credentials for users or services to access AWS resources. These credentials are often used in scenarios where you don't want to use long-term access keys, or when you need to provide short-term access to resources without creating permanent IAM users.
Here’s a breakdown of key concepts related to AWS STS:
Key Features of AWS STS:
Temporary Security Credentials: STS provides credentials that are valid for a limited duration (from a few minutes to several hours). After they expire, they cannot be used to access AWS resources.
Assume Roles: One of the most common uses of AWS STS is assuming roles. For example, you can allow a user or application to "assume" a role that gives it specific permissions, even if the user or app doesn't have those permissions by default. This is useful in cross-account scenarios, federated access, or when using roles to segregate access levels within the same account.
Federation: AWS STS enables identity federation, which allows users from external systems (like corporate directories or external identity providers) to access AWS resources without the need to create IAM users for them. This is done via standard protocols like SAML 2.0 or OpenID Connect.
Cross-Account Access: STS makes it easy to provide access to resources across different AWS accounts. A user in one account can assume a role in another account and gain access to resources, all without requiring the user to have an IAM user in the other account.
Reduced Credential Exposure: Since STS tokens are temporary, they limit the risk if credentials are compromised. After the expiration time, the token cannot be reused.
Example Use Cases:
- Delegating Access: You have a central administrative account, and you want to allow users from other AWS accounts to access your account’s resources. They can assume a role that you define in your account to temporarily gain the necessary permissions.
- Third-Party Access: You can give third-party vendors temporary access to your resources by letting them assume a role through STS without needing long-term credentials.
- Mobile Apps and IoT Devices: Instead of embedding long-term credentials in mobile or IoT devices, which can be insecure, you use STS to issue temporary credentials, which can be refreshed as needed.
Example of Using STS with AssumeRole:
aws sts assume-role --role-arn arn:aws:iam::123456789012:role/example-role --role-session-name session1
This command allows an identity to assume the role example-role in account 123456789012 and gain temporary credentials.
In summary, AWS STS is a powerful tool for managing short-term, secure access to AWS resources without the need for long-term credentials. It’s especially valuable in complex environments that require secure, time-bound access control, such as in cross-account access or federated identity setups.
AWS IAM Identity Policy - "Resource" discussion
https://chatgpt.com/share/a15d63d2-a124-4e5d-8195-830e27fb395d
Whether targeting a role or specific AWS resources is more common or advised depends on the context and the desired security model. Both approaches serve different purposes in AWS Identity and Access Management (IAM), and each has its own use cases:
1. Targeting an IAM Role (More common for users/roles):
Use Case: When you want to define a set of permissions for who can perform actions.
Common: This is a common practice for controlling permissions at a higher level. You assign policies to roles, and these roles are then assumed by users or services.
Advised: This approach is recommended when managing multiple users or services because you can easily modify or revoke permissions in one place (the role) without touching individual resources.
Example:
"Resource": "arn:aws:iam::123456789012:role/MyRole"
Advantages:
Easier Management: You can centrally manage access by assigning or removing permissions from the role without having to modify each resource.
Scalability: If multiple users or services need the same set of permissions, it's easier to manage by assigning roles rather than specific resource-level permissions.
When to Use:
For multi-user or multi-service environments where permissions are broadly defined.
For complex environments where you want to delegate access to external entities (cross-account access, etc.).
When you need to limit actions based on who or what is trying to perform the action.
2. Targeting Specific AWS Resources (More common for resources):
Use Case: When you want to limit what resources can be accessed or acted upon.
Common: Resource-based policies are used when you need fine-grained control over specific AWS resources. This ensures that only designated users, roles, or services can access or modify those resources.
Advised: Targeting specific resources is more advisable for high-security environments, or where sensitive data and actions need strict control.
Example:
"Resource": "arn:aws:s3:::my-bucket/my-object.txt"
Advantages:
Granular Control: You can enforce permissions on specific resources, ensuring tighter security.
Increased Security: You can prevent access to anything outside the explicitly defined resource, reducing the attack surface.
When to Use:
When you need to apply specific permissions to individual resources, like a particular S3 bucket, EC2 instance, or Lambda function.
When fine-grained permissions are necessary to ensure only specific actions are allowed on specific resources.
In cases where resources belong to sensitive environments or need to be tightly controlled.
Which is More Common?
IAM roles are generally more common in large-scale deployments and multi-service environments because they offer flexibility and ease of management.
Resource-based targeting is frequently used for controlling access to specific, high-security or sensitive resources.
Which is More Advised?
Targeting Roles is recommended when you want to manage permissions for who can perform actions (identity-based access control).
Targeting Specific Resources is more advisable when securing specific resources in high-security contexts (resource-based access control).
Best Practice:
In many cases, it's beneficial to combine both:
Use roles to manage who can access resources.
Use resource-level permissions to restrict what those roles (or identities) can do on specific resources.
For example, an S3 bucket might have a policy that allows only a specific IAM role to perform actions, and that role has a policy that allows specific users to assume it.