Replace AWSCloudShellFullAccess With Least-Privilege CloudShell Policy

Overview

Replace broad AWSCloudShellFullAccess permissions with a tightly scoped, least‑privilege CloudShell policy for your IAM users, groups, and roles. The plan identifies who is currently using the AWS-managed AWSCloudShellFullAccess policy, guides you through defining tailored CloudShell access requirements, creates and attaches a customer-managed least‑privilege policy, removes the old broad policy, and then validates both security posture and CloudShell functionality.

The workflow is divided into three phases:

• Assessment – Discover all principals relying on AWSCloudShellFullAccess and capture your detailed access requirements.
• Configuration – Build a least‑privilege CloudShell policy based on those requirements, attach it to the right principals, and detach AWSCloudShellFullAccess.
• Validation – Confirm that AWSCloudShellFullAccess is fully removed, that the new policy is correctly attached, and that CloudShell still works as intended for your users.

Execution Details

Assessment Phase

Identify principals with AWSCloudShellFullAccess attached

This phase starts by discovering your current exposure:

• Look up the AWS-managed AWSCloudShellFullAccess policy and record its ARN.
• Enumerate all IAM users, groups, and roles that have this policy attached directly.
• For groups with the policy, identify which users are members of those groups.
• Consolidate all affected principals into a single structured list, including type (user, group, role), name, ARN, and whether access is direct or via group.
• Verify that this consolidated list matches what IAM reports, ensuring an accurate baseline for remediation.

Guide the user to define least‑privilege CloudShell requirements

Using the consolidated list, the plan then helps you design the target permissions:

• Present the current set of principals using AWSCloudShellFullAccess so you can review who will be affected.
• Guide you to specify which AWS Regions should allow CloudShell usage (all enabled Regions or a defined subset).
• Help you define required CloudShell capabilities, such as starting/stopping sessions and managing CloudShell environments.
• Present options for restricting CloudShell usage, for example:
  • Limiting use to particular AWS accounts or roles to assume.
  • Applying IAM conditions to constrain network or resource access where appropriate.
• Capture whether certain principals or groups (e.g., admins vs. developers) need different levels of CloudShell access or extra permissions (such as managing persistent storage or accessing specific AWS services from CloudShell).
• Document and store the finalized least‑privilege requirements, including Region scope, baseline capabilities, any group-specific additions, and IAM condition keys to enforce the desired controls.

Configuration Phase

Create a least‑privilege CloudShell customer‑managed policy

With requirements defined, the plan focuses on authoring a tailored IAM policy:

• Establish a clear name and path for the new customer‑managed policy that will govern CloudShell access.
• Construct policy statements that allow only the minimal CloudShell actions needed (for example, actions required to start and manage CloudShell sessions).
• Scope permissions to the necessary resources and Regions, using precise ARNs and/or IAM conditions.
• Integrate IAM condition keys to enforce constraints such as allowed accounts, Regions, or other contextual checks you defined.
• Ensure the policy does not include unrelated or overly broad permissions beyond CloudShell usage.
• Create the customer‑managed policy, then record its ARN, name, and default version.
• Validate that the final document aligns with the documented least‑privilege requirements and contains the expected actions and statements.

Attach the least‑privilege policy to the right principals

Next, the plan transitions your environment to use the new policy:

• Load the list of IAM users, groups, and roles that previously relied on AWSCloudShellFullAccess.
• Use the recorded ARN of the least‑privilege CloudShell policy as the target.
• Determine which of those principals should receive the new policy, based on your documented access model (e.g., all affected principals or specific subsets).
• Attach the policy to each selected IAM user, group, and role.
• Capture the outcome for each principal, including successes, failures, and any relevant error details.
• Produce an updated inventory showing which principals now have the least‑privilege CloudShell policy and their attachment status.

Detach AWSCloudShellFullAccess from affected principals

Once the new policy is in place, the plan removes the broad AWS‑managed policy:

• Reload the consolidated list of principals that previously had AWSCloudShellFullAccess.
• For each listed user, group, and role, remove the AWSCloudShellFullAccess attachment where it still exists.
• Record the result of each detach operation and note any reasons for failure (such as policy already removed or access issues).
• Compile a list of principals from which AWSCloudShellFullAccess was successfully detached, as well as any where it could not be removed.
• Store these results in a structured format to support later verification that AWSCloudShellFullAccess is no longer in use across the environment.

Validation Phase

Confirm AWSCloudShellFullAccess is no longer attached

This step validates that the broad policy has been fully retired:

• Re-query IAM for the AWSCloudShellFullAccess policy and list all current user, group, and role attachments.
• Verify that there are no remaining IAM principals with this policy attached.
• If any attachments remain, identify those principals and determine whether they were missed or intentionally excluded from the remediation.
• Produce and store a validation summary that clearly states whether AWSCloudShellFullAccess has been fully removed from all intended principals.

Validate least‑privilege CloudShell policy attachments

The plan then checks that the new policy is correctly deployed:

• Confirm that the customer‑managed least‑privilege CloudShell policy exists using its ARN.
• List all IAM users, groups, and roles currently attached to this policy.
• Compare the actual attachments with the intended target principals defined during the configuration phase.
• Identify any missing attachments (principals that should have the policy but do not) and any unexpected attachments (principals that have the policy but were not intended to).
• Produce a report summarizing how well the current attachments align with the design, including any discrepancies that need follow-up.

User validation of CloudShell functionality

Finally, the plan ensures that CloudShell still works for your teams under the new restrictions:

• Guide you to select representative principals (for example, one or more users from each CloudShell user group) for functional testing.
• Have those principals attempt to launch CloudShell in allowed Regions and confirm sessions start successfully.
• Validate that CloudShell actions required for normal workflows function as expected for each test user, based on the requirements you previously defined.
• Confirm that CloudShell is blocked in Regions or contexts that should be restricted, where applicable.
• Capture any permission issues or unexpected access denials observed during testing.
• Document your final confirmation that CloudShell functionality meets the defined least‑privilege requirements—or note any gaps that need further adjustment.