CloudWatch VPC Changes Alarm Missing

• Query id: 9d0d4512-1959-43a2-a17f-72360ff06d1b
• Query name: CloudWatch VPC Changes Alarm Missing
• Platform: Terraform
• Severity: Medium
• Category: Observability
• CWE: 778
• URL: Github

Description

Ensure a log metric filter and alarm exist for VPC changes
Documentation

Code samples

Code samples with security vulnerabilities

Positive test num. 1 - tf file

resource "aws_cloudwatch_log_metric_filter" "CIS_VPC_Changes_Metric_Filter" {
  name           = "CIS-VPCChanges"
  pattern        = "{ ($.eventName = CreateVpc) || ($.eventName = DeleteVpc) || ($.eventName = ModifyVpcAttribute) || ($.eventName = AcceptVpcPeeringConnection) || ($.eventName = CreateVpcPeeringConnection) || ($.eventName = DeleteVpcPeeringConnection) || ($.eventName = RejectVpcPeeringConnection) || ($.eventName = AttachClassicLinkVpc) || ($.eventName = DetachClassicLinkVpc) || ($.eventName = DisableVpcClassicLink) || ($.eventName = EnableVpcClassicLink) }"
  log_group_name = aws_cloudwatch_log_group.CIS_CloudWatch_LogsGroup.name

  metric_transformation {
    name      = "CIS-VPCChanges"
    namespace = "CIS_Metric_Alarm_Namespace"
    value     = "1"
  }
}
resource "aws_cloudwatch_metric_alarm" "CIS_VPC_Changes_CW_Alarm" {
  alarm_name                = "CIS-3.14-VPCChanges"
  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 VPC 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_no_mfa_console_signin_metric_filter" {
  name           = "CIS-ConsoleSigninWithoutMFA"
  pattern        = "{ ($.eventName = \"ConsoleLogin\") && ($.additionalEventData.MFAUsed != \"Yes\") }"
  log_group_name = aws_cloudwatch_log_group.CIS_CloudWatch_LogsGroup.name

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

resource "aws_cloudwatch_metric_alarm" "cis_no_mfa_console_signin_cw_alarm" {
  alarm_name                = "CIS-3.2-ConsoleSigninWithoutMFA"
  comparison_operator       = "GreaterThanOrEqualToThreshold"
  evaluation_periods        = "1"
  metric_name               = aws_cloudwatch_log_metric_filter.cis_no_mfa_console_signin_metric_filter.id
  namespace                 = "CIS_Metric_Alarm_Namespace"
  period                    = "300"
  statistic                 = "Sum"
  threshold                 = "1"
  alarm_description         = "Monitoring for single-factor console logins will increase visibility into accounts that are not protected by MFA."
  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_VPC_Changes_Metric_Filter" {
  name           = "CIS-VPCChanges"
  pattern        = "{ ($.eventName = CreateVpc) || ($.eventName = ModifyVpcAttribute) || ($.eventName = AcceptVpcPeeringConnection) || ($.eventName = CreateVpcPeeringConnection) || ($.eventName = DeleteVpcPeeringConnection) || ($.eventName = RejectVpcPeeringConnection) || ($.eventName = AttachClassicLinkVpc) || ($.eventName = DetachClassicLinkVpc) || ($.eventName = EnableVpcClassicLink) }"
  log_group_name = aws_cloudwatch_log_group.CIS_CloudWatch_LogsGroup.name

  metric_transformation {
    name      = "CIS-VPCChanges"
    namespace = "CIS_Metric_Alarm_Namespace"
    value     = "1"
  }
}
resource "aws_cloudwatch_metric_alarm" "CIS_VPC_Changes_CW_Alarm" {
  alarm_name                = "CIS-3.14-VPCChanges"
  comparison_operator       = "GreaterThanOrEqualToThreshold"
  evaluation_periods        = "1"
  metric_name               = aws_cloudwatch_log_metric_filter.CIS_VPC_Changes_Metric_Filter.id
  namespace                 = "CIS_Metric_Alarm_Namespace"
  period                    = "300"
  statistic                 = "Sum"
  threshold                 = "1"
  alarm_description         = "Monitoring changes to VPC 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_VPC_Changes_Metric_Filter" {
  name           = "CIS-VPCChanges"
  pattern        = "{ ($.eventName = CreateVpc) || ($.eventName = DeleteVpc) || ($.eventName = ModifyVpcAttribute) || ($.eventName = AcceptVpcPeeringConnection) || ($.eventName = CreateVpcPeeringConnection) || ($.eventName = DeleteVpcPeeringConnection) || ($.eventName = RejectVpcPeeringConnection) || ($.eventName = AttachClassicLinkVpc) || ($.eventName = DetachClassicLinkVpc) || ($.eventName = DisableVpcClassicLink) || ($.eventName = EnableVpcClassicLink) }"
  log_group_name = aws_cloudwatch_log_group.CIS_CloudWatch_LogsGroup.name

  metric_transformation {
    name      = "CIS-VPCChanges"
    namespace = "CIS_Metric_Alarm_Namespace"
    value     = "1"
  }
}
resource "aws_cloudwatch_metric_alarm" "CIS_VPC_Changes_CW_Alarm" {
  alarm_name                = "CIS-3.14-VPCChanges"
  comparison_operator       = "GreaterThanOrEqualToThreshold"
  evaluation_periods        = "1"
  metric_name               = aws_cloudwatch_log_metric_filter.CIS_VPC_Changes_Metric_Filter.id
  namespace                 = "CIS_Metric_Alarm_Namespace"
  period                    = "300"
  statistic                 = "Sum"
  threshold                 = "1"
  alarm_description         = "Monitoring changes to VPC 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 = []
}