#
#####################################
##           Gherkin               ##
#####################################
# Rule Identifier:
#    CLOUD_TRAIL_LOG_FILE_VALIDATION_ENABLED
#
# Description:
#   Checks whether AWS CloudTrail creates a signed digest file with logs.
#
# Reports on:
#    AWS::CloudTrail::Trail
#
# Evaluates:
#    AWS CloudFormation
#
# Rule Parameters:
#    NA
#
# Scenarios:
# a) SKIP: when there are no CloudTrail Trails present
# b) PASS: when all CloudTrail Trails have EnableLogFileValidation parameter set true
# c) FAIL: when there are CloudTrail Trails with the EnableLogFileValidation parameter is set to false
# d) FAIL: when there are CloudTrail Trails with EnableLogFileValidation property not present
# e) SKIP: when metada has rule suppression for CLOUD_TRAIL_LOG_FILE_VALIDATION_ENABLED


#
# Select all CloudTrail Trail resources from incoming template (payload)
#
let cloudtrail_trails_log_validation = Resources.*[ Type == 'AWS::CloudTrail::Trail'
  Metadata.guard.SuppressedRules not exists or
  Metadata.guard.SuppressedRules.* != "CLOUD_TRAIL_LOG_FILE_VALIDATION_ENABLED"
]

rule CLOUD_TRAIL_LOG_FILE_VALIDATION_ENABLED when %cloudtrail_trails_log_validation !empty {
  %cloudtrail_trails_log_validation.Properties.EnableLogFileValidation EXISTS
  %cloudtrail_trails_log_validation.Properties.EnableLogFileValidation == true
  <<
    Violation: CloudTrail Trail should have Log File Validation enabled.
    Fix: Set the EnableLogFileValidation parameter to true.
  >>
}