Detection rules › YARA-L

AWS GuardDuty Command And Control Activity Detected

Severity
high
Type
Alert
Author
Google Cloud Security
Source
github.com/chronicle/detection-rules

Amazon GuardDuty detects Command and control activity in Amazon EC2, AWS Lambda or Amazon EKS Runtimes.

MITRE ATT&CK coverage

TacticTechniques
Command & Control

Rule body

// Copyright 2023 Google LLC. Licensed under Apache-2.0.

rule aws_guardduty_command_and_control_activity_detected {

  meta:
    author = "Google Cloud Security"
    description = "Amazon GuardDuty detects Command and control activity in Amazon EC2, AWS Lambda or Amazon EKS Runtimes."
    rule_id = "mr_dc0c33c7-35e3-44e2-b149-99212f3e54c6"
    rule_name = "AWS GuardDuty Command And Control Activity Detected"
    mitre_attack_tactic = "Command and Control"
    mitre_attack_technique = "Application Layer Protocol"
    mitre_attack_url = "https://attack.mitre.org/techniques/T1071/"
    mitre_attack_version = "v13.1"
    type = "Alert"
    data_source = "AWS GuardDuty"
    platform = "AWS"
    severity = "High"
    priority = "High"

  events:
    $guardduty.metadata.vendor_name = "AMAZON"
    $guardduty.metadata.product_name = "AWS GuardDuty"
    $guardduty.metadata.product_event_type = /C&CActivity/
    //Filter out sample findings
    $guardduty.security_result.about.labels["Sample"] != "true"

  outcome:
    $risk_score = max(35)
    $mitre_attack_tactic = "Command and Control"
    $mitre_attack_technique = "Application Layer Protocol"
    $mitre_attack_technique_id = "T1071"
    $event_count = count_distinct($guardduty.metadata.id)
    $principal_ip = array_distinct($guardduty.principal.ip)
    $principal_ip_country = array_distinct($guardduty.principal.ip_geo_artifact.location.country_or_region)
    $principal_ip_state = array_distinct($guardduty.principal.ip_geo_artifact.location.state)
    $principal_user_display_name = $guardduty.principal.user.user_display_name
    $aws_region = $guardduty.target.location.name
    $target_resource_name = $guardduty.target.resource.name
    $target_resource_product_object_id = $guardduty.target.resource.product_object_id
    $security_result_summary = array_distinct($guardduty.security_result.summary)
    $security_result_description = array_distinct($guardduty.security_result.description)
    $security_result_severity = array_distinct($guardduty.security_result.severity)
    $security_result_severity_details = array_distinct($guardduty.security_result.severity_details)
    $metadata_product_event_type = array_distinct($guardduty.metadata.product_event_type)

  condition:
    $guardduty
}

YARA-L rule structure

Condition

Fires when at least one $guardduty event.

Events

$guardduty

  • metadata.product_event_type matches "C&CActivity"
  • security_result.about.labels["Sample"] != "true"

Outcome

Outcome variables add context to a detection. When the rule generates an alert, $risk_score is displayed with it.

FieldExpression
risk_scoremax(35)
event_countcount_distinct($guardduty.metadata.id)
principal_iparray_distinct($guardduty.principal.ip)
principal_ip_countryarray_distinct($guardduty.principal.ip_geo_artifact.location.country_or_region)
principal_ip_statearray_distinct($guardduty.principal.ip_geo_artifact.location.state)
principal_user_display_name$guardduty.principal.user.user_display_name
aws_region$guardduty.target.location.name
target_resource_name$guardduty.target.resource.name
target_resource_product_object_id$guardduty.target.resource.product_object_id
security_result_summaryarray_distinct($guardduty.security_result.summary)
security_result_descriptionarray_distinct($guardduty.security_result.description)
security_result_severityarray_distinct($guardduty.security_result.severity)
security_result_severity_detailsarray_distinct($guardduty.security_result.severity_details)
metadata_product_event_typearray_distinct($guardduty.metadata.product_event_type)