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More Info:

AWS IAM policy configuration changes should be monitored using CloudWatch alarms.

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Risk Level

High

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Address

Security

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Compliance Standards

SOC2, HIPAA, ISO27001, AWSWAF, HITRUST, CISAWS, CBP, NISTCSF, PCIDSS

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Triage and Remediation

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Remediation

Using Console

  1. Configure CloudTrail to Deliver Logs to CloudWatch Logs:
    • Go to the AWS Management Console.
    • Open the CloudTrail service.
    • Select your trail.
    • Click on “Edit”.
    • In the “CloudWatch Logs” section, select an existing log group or create a new one.
    • Click “Save changes”.
  2. Create Metric Filter and Alarm:
    • Go to the CloudWatch service in the AWS Management Console.
    • In the left-hand navigation pane, choose “Logs” and then select the log group you configured in CloudTrail.
    • Click on “Create metric filter”.
    • Define a filter pattern that matches IAM policy changes. For example, you might use a pattern like { $.eventSource = "iam.amazonaws.com" && $.eventName = "AttachRolePolicy" }.
    • Click “Assign metric”.
    • Give your metric a name like IAMPolicyChangesEventCount.
    • Click “Create filter”.
    • Once your filter is created, you can set up an alarm based on this metric.

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  1. Create Metric Filter: 
    aws logs put-metric-filter \
  --log-group-name "YOUR_LOG_GROUP_NAME" \
  --filter-name "IAMPolicyChangesFilter" \
  --filter-pattern '{ $.eventSource = "iam.amazonaws.com" && $.eventName = "AttachRolePolicy" }' \
  --metric-transformations "metricName=IAMPolicyChangesEventCount,metricNamespace=CloudTrailMetrics,metricValue=1"
    Replace "YOUR_LOG_GROUP_NAME" with the name of your CloudTrail log group.
  2. Create CloudWatch Alarm (optional): Use the put-metric-alarm command to create an alarm based on the metric you created. 
import boto3

cloudwatch_logs = boto3.client('logs')
cloudwatch = boto3.client('cloudwatch')

# Create Metric Filter
response = cloudwatch_logs.put_metric_filter(
    logGroupName='YOUR_LOG_GROUP_NAME',
    filterName='IAMPolicyChangesFilter',
    filterPattern='{ $.eventSource = "iam.amazonaws.com" && $.eventName = "AttachRolePolicy" }',
    metricTransformations=[
        {
            'metricName': 'IAMPolicyChangesEventCount',
            'metricNamespace': 'CloudTrailMetrics',
            'metricValue': 1
        }
    ]
)

# Create CloudWatch Alarm (optional)
# You can use cloudwatch.put_metric_alarm() to create an alarm based on the metric
Replace "YOUR_LOG_GROUP_NAME" with the name of your CloudTrail log group.These steps should help you set up the IAMPolicyChangesEventCount metric in CloudWatch using the AWS Console, AWS CLI, or Python script. Remember to adjust the configuration according to your specific use case and environment.

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Additional Reading: