List every group for an IAM user

Part 89 of AWS from Zero. This lesson changes or inspects one IAM concept so the permission model stays understandable.

What we are learning

Group membership is one source of a user's identity-based permissions and should be part of every access review.

Before you run it

aws sts get-caller-identity
ACCOUNT_ID=$(aws sts get-caller-identity --query Account --output text)
USER_NAME="aws-zero-learner"
GROUP_NAME="aws-zero-readers"
ROLE_NAME="aws-zero-demo-role"

IAM is global rather than regional. Use a sandbox account and a delegated administrator identity, never root access keys.

The command

aws iam list-groups-for-user \
  --user-name "$USER_NAME"

IAM writes can take a short time to propagate. Inspect the resource after every change.

Inspect the result

aws iam list-groups-for-user \
  --user-name "$USER_NAME" \
  --query "Groups[].{Name:GroupName,Path:Path,Arn:Arn}" \
  --output table

Read the returned ARN, path, IDs, and attachment state instead of checking only the command exit code.

One tiny variation

aws iam get-group \
  --group-name "$GROUP_NAME" \
  --query "Users[].UserName" \
  --output text

Reverse the relationship to review everyone who inherits a group's policies.

Common mistake

A user can receive permissions directly, through several groups, through a permissions boundary, and through resource policies. Group review is necessary but incomplete.

Cleanup

# This lesson is read-only or reuses a named demo identity.
aws sts get-caller-identity

Keep shared demo identities only while following the IAM sequence. Part 125 removes them in dependency order.

Next, we will learn Remove an IAM user from a group safely.

Official AWS CLI reference