Find an AWS IAM user corresponding to an AWS Access Key (boto3)

find_user_from_access_key.py

# Find the IAM username belonging to the TARGET_ACCESS_KEY

import boto3
from botocore.exceptions import ClientError

iam = boto3.client('iam')

def find_user(key):
    try:
        key_info = iam.get_access_key_last_used(AccessKeyId=key)
        return key_info['UserName']
    except ClientError as e:
        print "Received error: %s", e
        if e.response['Error']['Code'] == 'AccessDenied':
            return "Key does not exist in target account"

try:
    print find_user("AKIAXXXXXXXXXXXXXXXX")
except ClientError as e:
    print "Received error: %s", e
    if e.response['Error']['Code'] == 'ExpiredToken':
        print "Please login to the target AWS account"

Just a heads-up this can be done with a single call using the "get_access_key_last_used" method of the boto3 IAM client.

http://boto3.readthedocs.io/en/latest/reference/services/iam.html#IAM.Client.get_access_key_last_used

@robperc Thanks for the heads up, that really speeds up the search. Added UPDATED_find_user_from_access_key.py for a simple example of that