This blog defines a number of services that are relevant to AWS security. It is recommended that you know all these services as well as possible.
IAM: This is the heart of all the authentication and authorization that AWS services perform. If there's one service you should learn in and out this is it. Admins can create IAM users and roles, associate access keys (for programmatic access) and assign permissions to each user and role. Developers can use the access keys to programmatically invoke all AWS services, subject to the permissions assigned to the user/role. Additionally almost all (if not all) services create service-linked roles and assume IAM roles to perform operations in another service. Here is one such example. It is possible to use IAM to control access by a user to an entire service, specific APIs in a service or in many cases to specific resources as well.
Resource Access Manager: This is a service that allows one account to share resources with another account. The person who uses the shared services can perform actions similar to the owner of the resources. This helps reduce operational costs and also the overall attack surface (due to there being lesser things to manage). However there are only a few resources that can be shared as of now. Here is a walkthrough of this service by the ever helpful Jeff Barr.
Cognito: Cognito handles authentication for web and mobile applications. This is Amazon's user directory against which users can authenticate against a user-pool and obtain a user-pool token. Users can authenticate directly against user records stored in Cognito or use a SSO provider such as Google or Facebook to authenticate. The user-pool token is then integrated with an identity pool to obtain temporary AWS credentials using the STS service (which does not have a web console :)), transparent to the user. These credentials are then used to access AWS resources.
Secrets Manager: Like the name suggests, this stores credentials in a secure manner using KMS. Instead of hard-coding credentials in source code or configuration files, they can be stored in a vault such as Secrets Manager. Applications can retrieve these credentials at run-time to implement their functionality. Passwords, API keys or anything else that is considered a secret can be stored here. Automatic rotation of these credentials is also possible for RDS (MySql, PostGres and Aurora) database passwords.
Guard Duty: This is a security monitoring tool that continuously studies different logs (Cloudtrail, VPC etc) and generates security findings. Rules in Guard duty are part AWS, part from AWS's security partners and users can themselves customize Guard Duty rules to help detect threats.
Inspector: This involves installing an agent on an EC2 instance that then scans for open ports, verifies if an instance is vulnerable to known CVEs or verifies the system against CIS benchmarks. In short it is Amazon's vulnerability scanner (for a few items) aimed at helping EC2 instance owners secure their instances better. If you're managing your instances yourself, this seems like a useful service to have, if you're willing to pay the extra money :). Note that charges are per instance so if you only have a few servers, this could be pretty cheap.
Macie: This is a fancy (fairly pricey) tool that AWS has to detect data leakage of specific information from S3 buckets (upto 3 Tb in size). It classifies data based on numerous very specific rules (for e.g 1 and 2). It's also integrated with KMS which means there is a way to scan bucket content that is also encrypted.
Single-Sign-On: This allows AWS to function as a SSO solution while being tightly integrated with a number of AWS services. It integrates with AWS Directory so you can store all your user information there and authenticate against it. Additionally, if you authenticate successfully once it will allow you access to all of the services across all the AWS accounts, that are integrated with SSO. There's also a way to migrate your entire Active Directory to AWS so your users can continue using the same passwords. It's very similar to IAM, in a way - except that IAM is just for the single account. Here is a good article about how AWS SSO works.
Directory Service: This is AWS's version of Active Directory. You can use SimpleAD which provides some features allowing easier management of EC2 instances. A more powerful version is the AWS Managed AD solution which allows you to access AWS apps, manage instances, use Azure Cloud apps, authenticate to an on-premise Active Directory over a VPN connection or share an AD domain hosted in another AWS account. You could also use an AD connector to allow EC2 instances to join an on-premise Active Directory. Users can then access the applications running on EC2 while authenticating against the on-premise Active Directory.
Certificate Manager: This is AWS's certificate authority solution that helps users of applications use certificates to secure communication to them over TLS. You can create certs inside ACM or import certificates from outside. ACM is integrated with a few other common services (not all). The certificate's private key is stored securely and encrypted using KMS.
Key Management Service: This is the AWS key vault that securely stores data keys that are used to encrypt data. You can choose to let AWS create an AWS master key or create a customer managed key yourself. This key never leaves KMS. The master key encrypts the data key, which is the key that you actually use to encrypt/decrypt data outside KMS. You can choose to create the data key outside and import it to KMS, where the master key encrypts it. This is envelope encryption, which offers better security compared to single-key encryption. Almost every piece of data needs encryption these days and very predictably - a lot of them are integrated with KMS.
Cloud HSM: A HSM is a server that contains specialized hardware optimized to perform cryptographic operations. It helps with operations such as these. HSM's are costly - be sure you need them. In CloudHSM you create a cluster, and then add HSMs to the cluster to help with data redundancy. KMS additionally integrates with CloudHSM to help store keys even more securely.
WAF and Shield: WAF is a web app firewall that monitors requests and allows/blocks traffic to the web-server that hosts content. You can choose which requests are acted upon. Shield helps protect applications against DDOS attacks. It has a Standard and Advanced mode (as the name suggests offers more protection). If you know what you're doing and don't have any fancy requirements, Shield Standard should be good enough.
SecurityHub: This is a one-stop to view the results of security scans done by Guard Duty, Inspector and Macie. Additionally, scan results from other partners are also listed here. It also claims to help businesses be compliant against CIS benchmarks.
Artifact: This is where you can go to look at all your agreements with AWS and manage them. Additionally, you can download numerous reports published by 3rd parties, verifying Amazon's compliance with numerous regulations.
IAM: This is the heart of all the authentication and authorization that AWS services perform. If there's one service you should learn in and out this is it. Admins can create IAM users and roles, associate access keys (for programmatic access) and assign permissions to each user and role. Developers can use the access keys to programmatically invoke all AWS services, subject to the permissions assigned to the user/role. Additionally almost all (if not all) services create service-linked roles and assume IAM roles to perform operations in another service. Here is one such example. It is possible to use IAM to control access by a user to an entire service, specific APIs in a service or in many cases to specific resources as well.
Resource Access Manager: This is a service that allows one account to share resources with another account. The person who uses the shared services can perform actions similar to the owner of the resources. This helps reduce operational costs and also the overall attack surface (due to there being lesser things to manage). However there are only a few resources that can be shared as of now. Here is a walkthrough of this service by the ever helpful Jeff Barr.
Cognito: Cognito handles authentication for web and mobile applications. This is Amazon's user directory against which users can authenticate against a user-pool and obtain a user-pool token. Users can authenticate directly against user records stored in Cognito or use a SSO provider such as Google or Facebook to authenticate. The user-pool token is then integrated with an identity pool to obtain temporary AWS credentials using the STS service (which does not have a web console :)), transparent to the user. These credentials are then used to access AWS resources.
Secrets Manager: Like the name suggests, this stores credentials in a secure manner using KMS. Instead of hard-coding credentials in source code or configuration files, they can be stored in a vault such as Secrets Manager. Applications can retrieve these credentials at run-time to implement their functionality. Passwords, API keys or anything else that is considered a secret can be stored here. Automatic rotation of these credentials is also possible for RDS (MySql, PostGres and Aurora) database passwords.
Guard Duty: This is a security monitoring tool that continuously studies different logs (Cloudtrail, VPC etc) and generates security findings. Rules in Guard duty are part AWS, part from AWS's security partners and users can themselves customize Guard Duty rules to help detect threats.
Inspector: This involves installing an agent on an EC2 instance that then scans for open ports, verifies if an instance is vulnerable to known CVEs or verifies the system against CIS benchmarks. In short it is Amazon's vulnerability scanner (for a few items) aimed at helping EC2 instance owners secure their instances better. If you're managing your instances yourself, this seems like a useful service to have, if you're willing to pay the extra money :). Note that charges are per instance so if you only have a few servers, this could be pretty cheap.
Macie: This is a fancy (fairly pricey) tool that AWS has to detect data leakage of specific information from S3 buckets (upto 3 Tb in size). It classifies data based on numerous very specific rules (for e.g 1 and 2). It's also integrated with KMS which means there is a way to scan bucket content that is also encrypted.
Single-Sign-On: This allows AWS to function as a SSO solution while being tightly integrated with a number of AWS services. It integrates with AWS Directory so you can store all your user information there and authenticate against it. Additionally, if you authenticate successfully once it will allow you access to all of the services across all the AWS accounts, that are integrated with SSO. There's also a way to migrate your entire Active Directory to AWS so your users can continue using the same passwords. It's very similar to IAM, in a way - except that IAM is just for the single account. Here is a good article about how AWS SSO works.
Directory Service: This is AWS's version of Active Directory. You can use SimpleAD which provides some features allowing easier management of EC2 instances. A more powerful version is the AWS Managed AD solution which allows you to access AWS apps, manage instances, use Azure Cloud apps, authenticate to an on-premise Active Directory over a VPN connection or share an AD domain hosted in another AWS account. You could also use an AD connector to allow EC2 instances to join an on-premise Active Directory. Users can then access the applications running on EC2 while authenticating against the on-premise Active Directory.
Certificate Manager: This is AWS's certificate authority solution that helps users of applications use certificates to secure communication to them over TLS. You can create certs inside ACM or import certificates from outside. ACM is integrated with a few other common services (not all). The certificate's private key is stored securely and encrypted using KMS.
Key Management Service: This is the AWS key vault that securely stores data keys that are used to encrypt data. You can choose to let AWS create an AWS master key or create a customer managed key yourself. This key never leaves KMS. The master key encrypts the data key, which is the key that you actually use to encrypt/decrypt data outside KMS. You can choose to create the data key outside and import it to KMS, where the master key encrypts it. This is envelope encryption, which offers better security compared to single-key encryption. Almost every piece of data needs encryption these days and very predictably - a lot of them are integrated with KMS.
Cloud HSM: A HSM is a server that contains specialized hardware optimized to perform cryptographic operations. It helps with operations such as these. HSM's are costly - be sure you need them. In CloudHSM you create a cluster, and then add HSMs to the cluster to help with data redundancy. KMS additionally integrates with CloudHSM to help store keys even more securely.
WAF and Shield: WAF is a web app firewall that monitors requests and allows/blocks traffic to the web-server that hosts content. You can choose which requests are acted upon. Shield helps protect applications against DDOS attacks. It has a Standard and Advanced mode (as the name suggests offers more protection). If you know what you're doing and don't have any fancy requirements, Shield Standard should be good enough.
SecurityHub: This is a one-stop to view the results of security scans done by Guard Duty, Inspector and Macie. Additionally, scan results from other partners are also listed here. It also claims to help businesses be compliant against CIS benchmarks.
Artifact: This is where you can go to look at all your agreements with AWS and manage them. Additionally, you can download numerous reports published by 3rd parties, verifying Amazon's compliance with numerous regulations.
