AWS Certification – Security & Identity Services – Cheat Sheet

IAM

  • securely control access to AWS services and resources
  • helps create and manage user identities and grant permissions for those users to access AWS resources
  • helps create groups for multiple users with similar permissions
  • not appropriate for application authentication
  • is Global and does not need to be migrated to a different region
  • helps define Policies,
    • in JSON format
    • all permissions are implicitly denied by default
    • most restrictive policy wins
  • IAM Role
    • helps grants and delegate access to users and services without the need of creating permanent credentials
    • IAM users or AWS services can assume a role to obtain temporary security credentials that can be used to make AWS API calls
    • needs Trust policy to define who and Permission policy to define what the user or service can access
    • used with Security Token Service (STS), a lightweight web service that provides temporary, limited privilege credentials for IAM users or for authenticated federated users
    • IAM role scenarios
      • Service access for e.g. EC2 to access S3 or DynamoDB
      • Cross Account access for users
        • with user within the same account
        • with user within an AWS account owned the same owner
        • with user from a Third Party AWS account with External ID for enhanced security
      • Identity Providers & Federation
        • Web Identity Federation, where the user can be authenticated using external authentication Identity providers like Amazon, Google or any OpenId IdP using AssumeRoleWithWebIdentity
        • Identity Provider using SAML 2.0, where the user can be authenticated using on premises Active Directory, Open Ldap or any SAML 2.0 compliant IdP using AssumeRoleWithSAML
        • For other Identity Providers, use Identity Broker to authenticate and provide temporary Credentials using AssumeRole (recommended) or GetFederationToken
  • IAM Best Practices
    • Do not use Root account for anything other than billing
    • Create Individual IAM users
    • Use groups to assign permissions to IAM users
    • Grant least privilege
    • Use IAM roles for applications on EC2
    • Delegate using roles instead of sharing credentials
    • Rotate credentials regularly
    • Use Policy conditions for increased granularity
    • Use CloudTrail to keep a history of activity
    • Enforce a strong IAM password policy for IAM users
    • Remove all unused users and credentials

CloudHSM

  • provides secure cryptographic key storage to customers by making hardware security modules (HSMs) available in the AWS cloud
  • single tenant, dedicated physical device to securely generate, store, and manage cryptographic keys used for data encryption
  • are inside the VPC (not EC2-classic) & isolated from the rest of the network
  • can use VPC peering to connect to CloudHSM from multiple VPCs
  • integrated with Amazon Redshift and Amazon RDS for Oracle
  • EBS volume encryption, S3 object encryption and key management can be done with CloudHSM but requires custom application scripting
  • is NOT fault tolerant and would need to build a cluster as if one fails all the keys are lost
  • expensive, prefer AWS Key Management Service (KMS) if cost is a criteria

AWS Directory Services

  • gives applications in AWS access to Active Directory services
  • different from SAML + AD, where the access is granted to AWS services through Temporary Credentials
  • Simple AD
    • least expensive but does not support Microsoft AD advance features
    • provides a Samba 4 Microsoft Active Directory compatible standalone directory service on AWS
    • No single point of Authentication or Authorization, as a separate copy is maintained
    • trust relationships cannot be setup between Simple AD and other Active Directory domains
    • Don’t use it, if the requirement is to leverage access and control through centralized authentication service
  • AD Connector
    • acts just as an hosted proxy service for instances in AWS to connect to on-premises Active Directory
    • enables consistent enforcement of existing security policies, such as password expiration, password history, and account lockouts, whether users are accessing resources on-premises or in the AWS cloud
    • needs VPN connectivity (or Direct Connect)
    • integrates with existing RADIUS-based MFA solutions to enabled multi-factor authentication
    • does not cache data which might lead to latency
  • Read-only Domain Controllers (RODCs)
    • works out as a Read-only Active Directory
    • holds a copy of the Active Directory Domain Service (AD DS) database and respond to authentication requests
    • they cannot be written to and are typically deployed in locations where physical security cannot be guaranteed
    • helps maintain a single point to authentication & authorization controls, however needs to be synced
  • Writable Domain Controllers
    • are expensive to setup
    • operate in a multi-master model; changes can be made on any writable server in the forest, and those changes are replicated to servers throughout the entire forest

AWS WAF

  • is a web application firewall that helps monitor the HTTP/HTTPS requests forwarded to CloudFront and allows controlling access to the content.
  • helps define Web ACLs, which is a combination of Rules, which is a combinations of Conditions and Action to block or allow
  • Third Party WAF
    • act as filters that apply a set of rules to web traffic to cover exploits like XSS and SQL injection and also help build resiliency against DDoS by mitigating HTTP GET or POST floods
    • WAF provides a lot of features like OWASP Top 10, HTTP rate limiting, Whitelist or blacklist, inspect and identify requests with abnormal patterns, CAPTCHA etc
    • a WAF sandwich pattern can be implemented where an autoscaled WAF sits between the Internet and Internal Load Balancer

 

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