UpdateSigningCertificate

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Event Information

• The UpdateSigningCertificate event in AWS for IAM refers to a change made to the signing certificate associated with an IAM user or IAM role.
• This event indicates that the signing certificate for an IAM user or IAM role has been updated, which can be used for signing API requests.
• It is important to monitor this event as it can help track changes to the authentication mechanism and ensure the security of the IAM user or IAM role.

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Examples

• Unauthorized access: If an attacker gains access to an IAM user’s credentials and is able to update the signing certificate, they can potentially impersonate the user and perform unauthorized actions within the AWS environment.
• Data breaches: If an unauthorized user gains access to an IAM user’s credentials and updates the signing certificate, they may be able to access sensitive data stored in AWS services, leading to a data breach.
• Service disruption: If an attacker gains control of an IAM user’s credentials and updates the signing certificate, they can potentially disrupt the availability of AWS services by modifying or deleting resources, affecting the overall security and functionality of the environment.

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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 set a strong password for an IAM user:

     aws iam update-login-profile --user-name <IAM_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 <IAM_USER_NAME> --serial-number <MFA_DEVICE_SERIAL_NUMBER> --authentication-code1 <CODE1> --authentication-code2 <CODE2>
     

3. Remove unnecessary IAM access keys:

   • Use the delete-access-key command to delete an IAM access key:

     aws iam delete-access-key --user-name <IAM_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 meets the desired complexity requirements (e.g., minimum length, use of special characters, etc.).
   • If a user’s password does not meet the requirements, use the update_login_profile method to force a password reset for that user.

import boto3

def enforce_strong_passwords():
    iam_client = boto3.client('iam')
    users = iam_client.list_users()['Users']
    
    for user in users:
        response = iam_client.get_login_profile(UserName=user['UserName'])
        if 'LoginProfile' in response:
            password = response['LoginProfile'].get('PasswordResetRequired')
            # Check password complexity requirements
            if not is_password_strong(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 already enabled.
   • If MFA is not enabled, use the enable_mfa method to enable it for that user.

import boto3

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

3. Monitor and rotate 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.
   • If access keys are found, check their age and determine if they need to be rotated.
   • If rotation is required, use the create_access_key and delete_access_key methods to generate a new access key and delete the old one.

import boto3
from datetime import datetime, timedelta

def rotate_access_keys():
    iam_client = boto3.client('iam')
    users = iam_client.list_users()['Users']
    
    for user in users:
        response = iam_client.list_access_keys(UserName=user['UserName'])
        for access_key in response['AccessKeyMetadata']:
            key_id = access_key['AccessKeyId']
            create_date = access_key['CreateDate']
            if (datetime.now() - create_date) > timedelta(days=90):
                new_key = iam_client.create_access_key(UserName=user['UserName'])
                iam_client.delete_access_key(UserName=user['UserName'], AccessKeyId=key_id)