DeleteUserPolicy

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Event Information

• The DeleteUserPolicy event in AWS for IAM refers to the action of deleting a policy attached to an IAM user.
• This event is triggered when a user policy is removed from an IAM user, either manually by an administrator or through an automated process.
• It is important to monitor this event as it can indicate changes in user permissions and access control within the AWS environment.

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Examples

• Unauthorized deletion of user policies: If security is impacted with DeleteUserPolicy in AWS for IAM, an example would be when an unauthorized user gains access to the IAM console or API and deletes user policies without proper authorization. This can lead to a loss of access control and compromise the security of the affected user’s resources.

• Accidental deletion of critical policies: Another example is when a user with legitimate access accidentally deletes critical policies using the DeleteUserPolicy API. This can result in the loss of necessary permissions for the affected user, potentially leading to service disruptions or unauthorized access to resources.

• Malicious deletion of policies: A third example is when an attacker gains unauthorized access to an IAM user’s credentials and uses the DeleteUserPolicy API to maliciously delete policies. This can be part of an attack strategy to escalate privileges, gain unauthorized access to resources, or disrupt the affected user’s operations. It highlights the importance of strong access controls and regular monitoring of IAM activities.

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Remediation

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Using Console

1. Example 1: Enforce strong password policy for IAM users

   • Step 1: Login to the AWS Management Console.
   • Step 2: Go to the IAM service.
   • Step 3: Click on “Account settings” in the left navigation pane.
   • Step 4: Under the “Password policy” section, click on “Edit”.
   • Step 5: Enable the “Require at least one uppercase letter” option.
   • Step 6: Enable the “Require at least one lowercase letter” option.
   • Step 7: Enable the “Require at least one number” option.
   • Step 8: Enable the “Require at least one non-alphanumeric character” option.
   • Step 9: Set the “Minimum password length” to an appropriate value.
   • Step 10: Click on “Apply password policy”.

2. Example 2: Enable multi-factor authentication (MFA) for IAM users

   • Step 1: Login to the AWS Management Console.
   • Step 2: Go to the IAM service.
   • Step 3: Click on “Users” in the left navigation pane.
   • Step 4: Select the IAM user for which you want to enable MFA.
   • Step 5: Click on the “Security credentials” tab.
   • Step 6: Under the “Multi-factor authentication (MFA)” section, click on “Manage”.
   • Step 7: Click on “Activate MFA”.
   • Step 8: Choose the appropriate MFA device option (e.g., virtual MFA device, hardware MFA device).
   • Step 9: Follow the on-screen instructions to set up the MFA device.
   • Step 10: Click on “Assign MFA”.

3. Example 3: Enable AWS CloudTrail for logging IAM events

   • Step 1: Login to the AWS Management Console.
   • Step 2: Go to the CloudTrail service.
   • Step 3: Click on “Trails” in the left navigation pane.
   • Step 4: Click on “Create trail”.
   • Step 5: Provide a name for the trail and choose the appropriate settings (e.g., log file validation, S3 bucket for storing logs).
   • Step 6: Under the “Management events” section, enable logging for IAM events.
   • Step 7: Click on “Create”.
   • Step 8: Once the trail is created, go to the IAM service.
   • Step 9: Click on “Policies” in the left navigation pane.
   • Step 10: Create a new IAM policy that allows the necessary CloudTrail actions and attach it to the IAM users or groups that require access to CloudTrail logs.

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Using CLI

1. Ensure IAM users have strong passwords:

• Use the update-login-profile command to enforce a strong password policy for IAM users:

  aws iam update-login-profile --user-name <user-name> --password <new-password> --password-reset-required
  

2. Enable multi-factor authentication (MFA) for IAM users:

• Use the enable-mfa-device command to enable MFA for an IAM user:

  aws iam enable-mfa-device --user-name <user-name> --serial-number <mfa-serial-number> --authentication-code1 <code1> --authentication-code2 <code2>
  

3. Rotate access keys regularly:

• Use the create-access-key command to generate a new access key for an IAM user:

  aws iam create-access-key --user-name <user-name>
  

• Use the delete-access-key command to delete the old access key:

  aws iam delete-access-key --user-name <user-name> --access-key-id <access-key-id>
  

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Using Python

1. Ensure IAM users have strong passwords:
   • Use the boto3 library in Python to retrieve a list of IAM users.
   • For each user, check if their password is strong by validating it against a set of password complexity rules.
   • If a user’s password is weak, use the update_login_profile method to force a password reset for that user.

import boto3
import re

def check_password_complexity(password):
    # Implement your password complexity rules here
    # Example: Password must be at least 8 characters long and contain at least one uppercase letter, one lowercase letter, and one digit
    if len(password) < 8 or not re.search(r'[A-Z]', password) or not re.search(r'[a-z]', password) or not re.search(r'\d', password):
        return False
    return True

def remediate_weak_passwords():
    iam_client = boto3.client('iam')
    users = iam_client.list_users()['Users']
    
    for user in users:
        login_profile = iam_client.get_login_profile(UserName=user['UserName'])
        if 'LoginProfile' in login_profile:
            password = login_profile['LoginProfile'].get('Password')
            if password and not check_password_complexity(password):
                iam_client.update_login_profile(UserName=user['UserName'], PasswordResetRequired=True)

2. Enable multi-factor authentication (MFA) for IAM users:
   • Use the boto3 library in Python to retrieve a list of IAM users.
   • For each user, check if MFA is enabled by calling the list_mfa_devices method.
   • If MFA is not enabled, use the enable_mfa method to enable it for the user.

import boto3

def remediate_missing_mfa():
    iam_client = boto3.client('iam')
    users = iam_client.list_users()['Users']
    
    for user in users:
        mfa_devices = iam_client.list_mfa_devices(UserName=user['UserName'])['MFADevices']
        if not mfa_devices:
            iam_client.enable_mfa(UserName=user['UserName'])

3. Remove unused IAM access keys:
   • Use the boto3 library in Python to retrieve a list of IAM users.
   • For each user, check if they have any access keys by calling the list_access_keys method.
   • If the user has unused access keys, use the delete_access_key method to remove them.

import boto3

def remediate_unused_access_keys():
    iam_client = boto3.client('iam')
    users = iam_client.list_users()['Users']
    
    for user in users:
        access_keys = iam_client.list_access_keys(UserName=user['UserName'])['AccessKeyMetadata']
        for access_key in access_keys:
            if access_key['Status'] == 'Inactive':
                iam_client.delete_access_key(UserName=user['UserName'], AccessKeyId=access_key['AccessKeyId'])