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cloud engineer

iam

AWS List Account Aliases

Here’s how to list account aliases. I have four profiles in my credentials. I’m looping through all four and printing the aliases.

#!/bin/bash
file='results-aws-account-aliases.txt'
> $file
declare -a account=("default" "one" "two" "three")
for i in "${account[@]}"
do
    echo '----------------------' >> $file
    echo 'Account: '$i >> $file
    aws iam list-account-aliases \
    --profile $i 
done

AWS CLI Search IAM UserID

Here’s how to search for an IAM user in AWS by filtering their access key.

aws iam list-users --query 'Users[?UserId==`AIDAxxxxxxxxxxxxxxxxx`]' \
--profile your-profile

The results only returns one user with that UserID.

[
    {
        "Path": "/",
        "UserName": "your-username",
        "UserId": "AIDAxxxxxxxxxxxxxxxxx",
        "Arn": "arn:aws:iam::xxxxxxxxxxxx:user/sa-lucidchart",
        "CreateDate": "2019-04-15T15:53:18+00:00"
    }
]

AWS IAM MFA

Here’s how to give AWS IAM users the ability to manage their own (MFA) Multi Factor Authentication. MFA makes your AWS console secure. AWS IAM users will be able to turn on MFA, using virtual devices such as Google Authenticator to secure their cloud accounts. Here’s the policy.

{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Sid": "AllowViewAccountInfo",
      "Effect": "Allow",
      "Action": "iam:ListVirtualMFADevices",
      "Resource": "*"
    },
    {
      "Sid": "AllowManageOwnVirtualMFADevice",
      "Effect": "Allow",
      "Action": [
        "iam:CreateVirtualMFADevice",
        "iam:DeleteVirtualMFADevice"
      ],
      "Resource": "arn:aws:iam::*:mfa/${aws:username}"
    },
    {
      "Sid": "AllowManageOwnUserMFA",
      "Effect": "Allow",
      "Action": [
        "iam:DeactivateMFADevice",
        "iam:EnableMFADevice",
        "iam:ListUsers",
        "iam:GetUser",
        "iam:ListMFADevices",
        "iam:ResyncMFADevice"
      ],
      "Resource": "arn:aws:iam::*:user/${aws:username}"
    }
  ]
}

AWS Rotate IAM Keys

Here’s a script that will rotate AWS IAM keys.

#!/bin/bash
# set files
user='johndoe'
newkey='/root/new-access-key.json'
oldkey='/root/old-access-key.json'
credentials='/root/.aws/credentials'
# get old credentials
aws iam list-access-keys --user-name $user > $oldkey
okey=$(jq .AccessKeyMetadata[0].AccessKeyId $oldkey | tr -d \")
# create new key
aws iam create-access-key --user-name $user > $newkey
# get new access keys and new secret
nkey=$(jq .AccessKey.AccessKeyId $newkey | tr -d \")
nsecret=$(jq .AccessKey.SecretAccessKey $newkey | tr -d \")
# backup old credentials
cp /root/.aws/credentials /root/.aws/credentials-backup
# store the new key
echo '[default]' > $credentials
echo 'aws_access_key_id = ' $nkey >> $credentials
echo 'aws_secret_access_key = '$nsecret >> $credentials
sleep 10
# delete old key
aws iam delete-access-key --user-name $user --access-key-id $okey
rm $newkey
rm $oldkey

The script performs the following:

  1. Retrieves the current key
  2. Creates a new key
  3. Backup the current credentials file
  4. Create a new credentials file
  5. Deletes the old key
  6. Deletes the temp files
  7. Done

S3 Browser IAM Assume Role

S3 Browser is a free Windows client for accessing AWS S3 buckets. You can access S3 buckets with an interface similar to File Manager. A typical setup requires that you use access and secret keys to connect to the S3 browser. However, if the server is in the cloud, it’s better that use a machine profile with an assume role. The assume role gets temporary credentials until they expire. They are automatically rotated by AWS behind the scenes for you. This is much safer process than storing key credentials in the cloud. The good news is, S3 Browser support IAM assume roles. Here’s the setup instructions to get your S3 Browser configured using IAM assume role. Here’s IAM role explained.

Standard S3 Policy

Here’s a standard S3 policy to grant an IAM user access to a bucket within an AWS account. User is allowed to add, update, and delete objects. These 3 actions s3:ListAllMyBuckets, s3:GetBucketLocation, and s3:ListBucket are the additional permissions required to access the console. Also, the s3:PutObjectAcl and the s3:GetObjectAcl actions are required to be able to copy, cut, and paste objects within the console. 

{
   "Version":"2012-10-17",
   "Statement":[
      {
         "Effect":"Allow",
         "Action":[
            "s3:ListAllMyBuckets"
         ],
         "Resource":"arn:aws:s3:::*"
      },
      {
         "Effect":"Allow",
         "Action":[
            "s3:ListBucket",
            "s3:GetBucketLocation"
         ],
         "Resource":"arn:aws:s3:::examplebucket"
      },
      {
         "Effect":"Allow",
         "Action":[
            "s3:PutObject",
            "s3:PutObjectAcl",
            "s3:GetObject",
            "s3:GetObjectAcl",
            "s3:DeleteObject"
         ],
         "Resource":"arn:aws:s3:::examplebucket/*"
      }
   ]
}

AWS Display IAM Certificates

SSL certificates were uploaded to IAM prior to Certificate Manager. Unfortunately, the certificates are not visible from the IAM console. There’s no way to view when a certificate is expiring. So, here’s how to display IAM certificates from the AWS CLI.

aws iam list-server-certificates