What are AWS IAM roles?
An AWS Identity and Access Management (IAM) role is a security identity you can create in your account that has specific permissions. It is not uniquely associated with one person or application. Instead, it is intended to be assumable by trusted entities that need it, such as IAM users, applications, or AWS services like Amazon EC2.
When an entity assumes a role, it abandons its own permissions and gains the temporary security credentials assigned to that role for the session - a capability that Blackstone's security team leveraged for secure cross-account access in their complex cloud environment. This mechanism is a core component of AWS security, as it allows you to grant access to your resources without sharing long-term credentials.
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How AWS IAM Roles Work
An IAM role functions based on two attached policies:
Trust Policy: This policy specifies the principals (users, applications, or services) that are allowed to assume the role. It establishes a trust relationship between the role and the entity that needs its permissions.
Permissions Policy: This is a standard identity-based policy that defines the specific actions and resources the role is allowed to access. For example, it might grant read-only access to an S3 bucket or full administrative access to EC2 instances.
When a trusted entity needs to act, it makes a request to the AWS Security Token Service (STS) to assume the role. If the trust policy allows it, STS returns a set of temporary credentials that the entity can use to make requests to other AWS services.
IAM roles vs users and policies
It's easy to confuse IAM roles, users, and policies, but they serve distinct purposes:
IAM User: Represents a person or application and has permanent, long-term credentials (a password or access keys). A user is a distinct identity within your AWS account.
IAM Role: An identity that can be assumed by other entities. It does not have its own long-term credentials and provides temporary credentials upon assumption. Roles are ideal for delegating access.
IAM Policy: A document that defines permissions. It is not an identity itself but is attached to users, groups, or roles to grant them access to AWS resources. A role must have both a permissions policy and a trust policy to function.
Common AWS IAM role security risks
Key risks include:
Overly Permissive Roles: Granting wildcard permissions (
*:*) or more access than an application needs. If compromised, these roles provide attackers with a wide blast radius.Misconfigured Trust Policies: Allowing untrusted or overly broad principals to assume a role, such as an entire AWS account or a public service, opening the door for unauthorized access.
Privilege Escalation Paths: A role that allows an entity to modify other IAM policies or create new roles can be exploited by an attacker to gain administrative control over the environment.
Stale or Unused Roles: Forgotten roles that are no longer needed but remain active are an unnecessary security risk and a common target for attackers - BMW discovered they had significantly more cloud workloads than expected when they gained full visibility into their environment.
Wiz provides complete visibility into these risks by mapping out effective permissions and identifying toxic combinations that create attack paths to your critical assets.
AWS IAM role security best practices
To secure your IAM roles, you should adopt a proactive security posture focused on minimizing risk. Follow these best practices:
Enforce Least Privilege: Always grant only the minimum permissions required for a specific task. Avoid using broad permissions and instead define granular access.
Use Conditions in Policies: Strengthen your policies by adding conditions that restrict access based on factors like source IP address, time of day, or whether multi-factor authentication (MFA) was used.
Regularly Audit and Rotate Roles: Continuously review role usage and permissions. Remove any roles that are no longer necessary and rotate credentials where applicable. Wiz's CIEM capabilities automate this process by identifying overprivileged and inactive roles.
Secure Trust Policies: Be explicit about which principals can assume a role. Avoid using wildcards in the principal element of a trust policy.
Use IAM Roles for EC2 and Compute Services: Instead of storing long-term access keys on an instance, assign an IAM role to it. This allows applications on the instance to automatically receive temporary credentials.
To further enhance your incident response capabilities for AWS environments, consider consulting a dedicated playbook for credential management and breach scenarios.
Tools for AWS IAM role security
Beyond best practices, take advantage of tools that automate IAM auditing and provide fine-grained control over access to AWS services and resources:
AWS IAM Access Analyzer: You can use this tool to detect permissions that accidentally allow external access to your AWS resources. It also generates reports so you can confirm IAM roles are tightly controlled and adhere to the principle of least privilege.
IAM Identity Center: Through the IAM Identity Center, you can manage IAM roles and user permissions across AWS services and accounts.
AWS identity federation: Identity federation enables establishing trust relationships between external identity providers (IdPs) and AWS environments. With that relationship in place, users can authenticate and assume IAM roles through their existing organizational credentials / IdPs. Keep in mind that these external IdPs need to be compatible with OpenID connect (OIDC) or security assertion markup language (SAML).
AWS CloudTrail: CloudTrail captures detailed logs of all IAM-related actions, such as changes to roles or policies, which you can use to find unauthorized changes.
IAM policy simulator: The IAM policy simulator is a great way to test the effects of IAM role policies before deployment.
Aside from AWS’ native solutions, there are specialized tools for cloud infrastructure entitlement management (CIEM) that focus on the management and security of identities and access entitlements within cloud environments. These third-party tools often provide broader visibility and control over identities and policies and even work for multi-cloud environments. For example, Wiz stands out because of its cross-platform coverage and its ability to automate remediation across cloud environments.
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How Wiz secures your AWS IAM roles
Wiz provides a unified platform to manage and secure your entire cloud identity fabric. With Wiz Cloud Infrastructure Entitlement Management (CIEM), you can proactively identify and eliminate identity-based risks across your AWS environment.
The Wiz Security Graph connects identity risks with other cloud vulnerabilities, network exposures, and misconfigurations to visualize real attack paths. This allows you to prioritize the most critical issues first, such as an overprivileged role on a publicly exposed virtual machine. With agentless visibility, Wiz connects in minutes to give you a complete inventory of all roles and their effective permissions, helping you enforce least privilege at scale.
Ready to secure your AWS IAM roles? See how Wiz identifies overprivileged roles, eliminates unused permissions, and prevents identity-based attacks. Request a demo to explore how Wiz can secure your cloud environment.
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