CloudWatch Route Table Changes Alarm Missing

• Query id: 2285e608-ddbc-47f3-ba54-ce7121e31216
• Query name: CloudWatch Route Table Changes Alarm Missing
• Platform: Terraform
• Severity: Low
• Category: Observability
• URL: Github

Description

Ensure a log metric filter and alarm exist for route table changes
Documentation

Code samples

Code samples with security vulnerabilities

Positive test num. 1 - tf file

resource "aws_cloudwatch_log_metric_filter" "cis_route_table_changes_metric_filter" {
  name           = "CIS-RouteTableChanges"
  pattern        = "{ ($.eventName = CreateRoute) || ($.eventName = CreateRouteTable) || ($.eventName = ReplaceRoute) || ($.eventName = ReplaceRouteTableAssociation) || ($.eventName = DeleteRouteTable) || ($.eventName = DeleteRoute) || ($.eventName = DisassociateRouteTable) }"
  log_group_name = aws_cloudwatch_log_group.CIS_CloudWatch_LogsGroup.name

  metric_transformation {
    name      = "CIS-RouteTableChanges"
    namespace = "CIS_Metric_Alarm_Namespace"
    value     = "1"
  }
}
resource "aws_cloudwatch_metric_alarm" "cis_route_table_changes_cw_alarm" {
  alarm_name                = "CIS-3.13-RouteTableChanges"
  comparison_operator       = "GreaterThanOrEqualToThreshold"
  evaluation_periods        = "1"
  metric_name               = "XXXX NOT YOUR FILTER XXXX"
  namespace                 = "CIS_Metric_Alarm_Namespace"
  period                    = "300"
  statistic                 = "Sum"
  threshold                 = "1"
  alarm_description         = "Monitoring changes to route tables will help ensure that all VPC traffic flows through an expected path."
  alarm_actions             = [aws_sns_topic.CIS_Alerts_SNS_Topic.arn]
  insufficient_data_actions = []
}

Positive test num. 2 - tf file

resource "aws_cloudwatch_log_metric_filter" "cis_unauthorized_api_calls_metric_filter" {
  name           = "CIS-UnauthorizedAPICalls"
  pattern        = "{ ($.errorCode = \"*UnauthorizedOperation\") || ($.errorCode = \"AccessDenied*\") }"
  log_group_name = aws_cloudwatch_log_group.CIS_CloudWatch_LogsGroup.name

  metric_transformation {
    name      = "CIS-UnauthorizedAPICalls"
    namespace = "CIS_Metric_Alarm_Namespace"
    value     = "1"
  }
}

resource "aws_cloudwatch_metric_alarm" "cis_unauthorized_api_calls_cw_alarm" {
  alarm_name                = "CIS-3.1-UnauthorizedAPICalls"
  comparison_operator       = "GreaterThanOrEqualToThreshold"
  evaluation_periods        = "1"
  metric_name               = aws_cloudwatch_log_metric_filter.cis_unauthorized_api_calls_metric_filter.id
  namespace                 = "CIS_Metric_Alarm_Namespace"
  period                    = "300"
  statistic                 = "Sum"
  threshold                 = "1"
  alarm_description         = "Monitoring unauthorized API calls will help reveal application errors and may reduce time to detect malicious activity."
  alarm_actions             = [aws_sns_topic.cis_alerts_sns_topic.arn]
  insufficient_data_actions = []
}

Positive test num. 3 - tf file

resource "aws_cloudwatch_log_metric_filter" "cis_route_table_changes_metric_filter" {
  name           = "CIS-RouteTableChanges"
  pattern        = "{ ($.eventName = CreateRoute) || ($.eventName = ReplaceRouteTableAssociation) || ($.eventName = DeleteRouteTable) || ($.eventName = DeleteRoute) || ($.eventName = DisassociateRouteTable) }"
  log_group_name = aws_cloudwatch_log_group.CIS_CloudWatch_LogsGroup.name

  metric_transformation {
    name      = "CIS-RouteTableChanges"
    namespace = "CIS_Metric_Alarm_Namespace"
    value     = "1"
  }
}
resource "aws_cloudwatch_metric_alarm" "cis_route_table_changes_cw_alarm" {
  alarm_name                = "CIS-3.13-RouteTableChanges"
  comparison_operator       = "GreaterThanOrEqualToThreshold"
  evaluation_periods        = "1"
  metric_name               = aws_cloudwatch_log_metric_filter.cis_route_table_changes_metric_filter.id
  namespace                 = "CIS_Metric_Alarm_Namespace"
  period                    = "300"
  statistic                 = "Sum"
  threshold                 = "1"
  alarm_description         = "Monitoring changes to route tables will help ensure that all VPC traffic flows through an expected path."
  alarm_actions             = [aws_sns_topic.CIS_Alerts_SNS_Topic.arn]
  insufficient_data_actions = []
}

Code samples without security vulnerabilities

Negative test num. 1 - tf file

resource "aws_cloudwatch_log_metric_filter" "cis_route_table_changes_metric_filter" {
  name           = "CIS-RouteTableChanges"
  pattern        = "{ ($.eventName = CreateRoute) || ($.eventName = CreateRouteTable) || ($.eventName = ReplaceRoute) || ($.eventName = ReplaceRouteTableAssociation) || ($.eventName = DeleteRouteTable) || ($.eventName = DeleteRoute) || ($.eventName = DisassociateRouteTable) }"
  log_group_name = aws_cloudwatch_log_group.CIS_CloudWatch_LogsGroup.name

  metric_transformation {
    name      = "CIS-RouteTableChanges"
    namespace = "CIS_Metric_Alarm_Namespace"
    value     = "1"
  }
}
resource "aws_cloudwatch_metric_alarm" "cis_route_table_changes_cw_alarm" {
  alarm_name                = "CIS-3.13-RouteTableChanges"
  comparison_operator       = "GreaterThanOrEqualToThreshold"
  evaluation_periods        = "1"
  metric_name               = aws_cloudwatch_log_metric_filter.cis_route_table_changes_metric_filter.id
  namespace                 = "CIS_Metric_Alarm_Namespace"
  period                    = "300"
  statistic                 = "Sum"
  threshold                 = "1"
  alarm_description         = "Monitoring changes to route tables will help ensure that all VPC traffic flows through an expected path."
  alarm_actions             = [aws_sns_topic.CIS_Alerts_SNS_Topic.arn]
  insufficient_data_actions = []
}