Module: cloudtrail-cloudwatch-alarms

Terraform module for creating alarms for tracking important changes and occurances from cloudtrail.

This module creates a set of filter metrics and alarms based on the security best practices covered in the AWS CIS Foundations Benchmark guide.

Usage

module "metric_configs" {
  source  = "cloudposse/config/yaml"
  # Cloud Posse recommends pinning every module to a specific version
  # version     = "x.x.x"

  map_config_local_base_path = "./catalog"
  map_config_paths           = "*.yaml"

  context = module.this.context
}

module "cloudtrail_api_alarms" {
  source  = "cloudposse/cloudtrail-cloudwatch-alarms/aws"
  # Cloud Posse recommends pinning every module to a specific version
  # version     = "x.x.x"

  log_group_name = "${aws_cloudwatch_log_group.default.name}"
  metrics = module.metric_configs.map_configs
}

For detailed usage which includes setting up cloudtrail, cloudwatch logs, roles, policies, and the s3 bucket - as well as using this module see the example directory

For aditional CIS rules and controls https://docs.aws.amazon.com/securityhub/latest/userguide/securityhub-cis-controls.html#securityhub-cis-controls-3.8

Examples

Here's a complete example of using this terraform-aws-cloudtrail-cloudwatch-alarms module.

Requirements

Name	Version
terraform	>= 1.0
aws	>= 4.0

Providers

Name	Version
aws	>= 4.0

Modules

Name	Source	Version
aws_sns_topic_label	cloudposse/label/null	0.25.0
sns_kms_key	cloudposse/kms-key/aws	0.10.0
sns_kms_key_label	cloudposse/label/null	0.25.0
this	cloudposse/label/null	0.25.0

Resources

Name	Type
aws_cloudwatch_dashboard.combined	resource
aws_cloudwatch_dashboard.individual	resource
aws_cloudwatch_log_metric_filter.default	resource
aws_cloudwatch_metric_alarm.default	resource
aws_sns_topic.default	resource
aws_sns_topic_policy.default	resource
aws_caller_identity.default	data source
aws_iam_policy_document.sns_kms_key_policy	data source
aws_iam_policy_document.sns_topic_policy	data source
aws_region.current	data source

Inputs

Name	Description	Type	Default	Required
additional_endpoint_arns	Any alert endpoints, such as autoscaling, or app scaling endpoint arns that will respond to an alert	list(string)	[]	no
additional_tag_map	Additional key-value pairs to add to each map in tags_as_list_of_maps. Not added to tags or id. This is for some rare cases where resources want additional configuration of tags and therefore take a list of maps with tag key, value, and additional configuration.	map(string)	{}	no
attributes	ID element. Additional attributes (e.g. workers or cluster) to add to id, in the order they appear in the list. New attributes are appended to the end of the list. The elements of the list are joined by the delimiter and treated as a single ID element.	list(string)	[]	no
context	Single object for setting entire context at once. See description of individual variables for details. Leave string and numeric variables as null to use default value. Individual variable settings (non-null) override settings in context object, except for attributes, tags, and additional_tag_map, which are merged.	any	{ "additional_tag_map": {}, "attributes": [], "delimiter": null, "descriptor_formats": {}, "enabled": true, "environment": null, "id_length_limit": null, "label_key_case": null, "label_order": [], "label_value_case": null, "labels_as_tags": [ "unset" ], "name": null, "namespace": null, "regex_replace_chars": null, "stage": null, "tags": {}, "tenant": null }	no
dashboard_enabled	When true a dashboard that displays the statistics as a line graph will be created in CloudWatch	bool	true	no
delimiter	Delimiter to be used between ID elements. Defaults to - (hyphen). Set to "" to use no delimiter at all.	string	null	no
descriptor_formats	Describe additional descriptors to be output in the descriptors output map. Map of maps. Keys are names of descriptors. Values are maps of the form {<br/> format = string<br/> labels = list(string)<br/>} (Type is any so the map values can later be enhanced to provide additional options.) format is a Terraform format string to be passed to the format() function. labels is a list of labels, in order, to pass to format() function. Label values will be normalized before being passed to format() so they will be identical to how they appear in id. Default is {} (descriptors output will be empty).	any	{}	no
enabled	Set to false to prevent the module from creating any resources	bool	null	no
environment	ID element. Usually used for region e.g. 'uw2', 'us-west-2', OR role 'prod', 'staging', 'dev', 'UAT'	string	null	no
id_length_limit	Limit id to this many characters (minimum 6). Set to 0 for unlimited length. Set to null for keep the existing setting, which defaults to 0. Does not affect id_full.	number	null	no
kms_master_key_id	The ID or alias of the customer master key (CMK) to use for encrypting the Amazon SNS topic. The CMK must have its resource-based policy allow the service cloudwatch.amazonaws.com to perform kms:Decrypt and kms:GenerateDataKey on it. If this variable is not supplied, a CMK with the sufficient resource-based policy will be created and used when configuring encryption for the SNS topic.	string	null	no
label_key_case	Controls the letter case of the tags keys (label names) for tags generated by this module. Does not affect keys of tags passed in via the tags input. Possible values: lower, title, upper. Default value: title.	string	null	no
label_order	The order in which the labels (ID elements) appear in the id. Defaults to ["namespace", "environment", "stage", "name", "attributes"]. You can omit any of the 6 labels ("tenant" is the 6th), but at least one must be present.	list(string)	null	no
label_value_case	Controls the letter case of ID elements (labels) as included in id, set as tag values, and output by this module individually. Does not affect values of tags passed in via the tags input. Possible values: lower, title, upper and none (no transformation). Set this to title and set delimiter to "" to yield Pascal Case IDs. Default value: lower.	string	null	no
labels_as_tags	Set of labels (ID elements) to include as tags in the tags output. Default is to include all labels. Tags with empty values will not be included in the tags output. Set to [] to suppress all generated tags. Notes: The value of the name tag, if included, will be the id, not the name. Unlike other null-label inputs, the initial setting of labels_as_tags cannot be changed in later chained modules. Attempts to change it will be silently ignored.	set(string)	[ "default" ]	no
log_group_name	The cloudtrail cloudwatch log group name	string	n/a	yes
log_group_region	The log group region that should be monitored for unauthorised AWS API Access. Current region used if none provided.	string	""	no
metric_namespace	A namespace for grouping all of the metrics together	string	"CISBenchmark"	no
metrics	The cloudwatch metrics and corresponding alarm definitions	map(object({ metric_name = string filter_pattern = string metric_namespace = string metric_value = string alarm_name = string alarm_comparison_operator = string alarm_evaluation_periods = string alarm_period = string alarm_statistic = string alarm_treat_missing_data = string alarm_threshold = string alarm_description = string }))	{}	no
name	ID element. Usually the component or solution name, e.g. 'app' or 'jenkins'. This is the only ID element not also included as a tag. The "name" tag is set to the full id string. There is no tag with the value of the name input.	string	null	no
namespace	ID element. Usually an abbreviation of your organization name, e.g. 'eg' or 'cp', to help ensure generated IDs are globally unique	string	null	no
regex_replace_chars	Terraform regular expression (regex) string. Characters matching the regex will be removed from the ID elements. If not set, "/[^a-zA-Z0-9-]/" is used to remove all characters other than hyphens, letters and digits.	string	null	no
sns_policy_enabled	Attach a policy that allows the notifications through to the SNS topic endpoint	bool	false	no
sns_topic_arn	An SNS topic ARN that has already been created. Its policy must already allow access from CloudWatch Alarms, or set add_sns_policy to true	string	null	no
stage	ID element. Usually used to indicate role, e.g. 'prod', 'staging', 'source', 'build', 'test', 'deploy', 'release'	string	null	no
tags	Additional tags (e.g. {'BusinessUnit': 'XYZ'}). Neither the tag keys nor the tag values will be modified by this module.	map(string)	{}	no
tenant	ID element _(Rarely used, not included by default)_. A customer identifier, indicating who this instance of a resource is for	string	null	no

Outputs

Name	Description
dashboard_combined	URL to CloudWatch Combined Metric Dashboard
dashboard_individual	URL to CloudWatch Individual Metric Dashboard
sns_topic_arn	The ARN of the SNS topic used

Metrics Tracked

Alarm's Name	Description
AuthorizationFailureCount	Alarms when an unauthorized API call is made.
S3BucketActivityEventCount	Alarms when an API call is made to S3 to put or delete a Bucket, Bucket Policy or Bucket ACL.
SecurityGroupEventCount	Alarms when an API call is made to create, update or delete a Security Group.
NetworkAclEventCount	Alarms when an API call is made to create, update or delete a Network ACL.
GatewayEventCount	Alarms when an API call is made to create, update or delete a Customer or Internet Gateway.
VpcEventCount	Alarms when an API call is made to create, update or delete a VPC, VPC peering connection or VPC connection to classic.
EC2InstanceEventCount	Alarms when an API call is made to create, terminate, start, stop or reboot an EC2 instance.
EC2LargeInstanceEventCount	Alarms when an API call is made to create, terminate, start, stop or reboot a 4x-large or greater EC2 instance.
CloudTrailEventCount	Alarms when an API call is made to create, update or delete a .cloudtrail. trail, or to start or stop logging to a trail.
ConsoleSignInFailureCount	Alarms when an unauthenticated API call is made to sign into the console.
IAMPolicyEventCount	Alarms when an API call is made to change an IAM policy.
ConsoleSignInWithoutMfaCount	Alarms when a user logs into the console without MFA.
RootAccountUsageCount	Alarms when a root account usage is detected.
KMSKeyPendingDeletionErrorCount	Alarms when a customer created KMS key is pending deletion.
AWSConfigChangeCount	Alarms when AWS Config changes.
RouteTableChangesCount	Alarms when route table changes are detected.

Dashboard Created

Two CloudWatch Dashboards can be created as well, and will be automatically created by default.

Credits

The alarm metric names, descriptions, and filters from this repository were used.

With many thanks to Anton Babenko for pointing it out and saving us a lot of time scouring reference documents and describing alarms!