Detection rules › YARA-L
WHOIS Recently Created Domain Access
Detects access attempts to a newly created domain via WHOIS enrichment.
Telemetry coverage
Rule body
// Copyright 2023 Google LLC. Licensed under Apache-2.0.
rule whois_recently_created_domain_access {
meta:
author = "Google Cloud Security"
description = "Detects access attempts to a newly created domain via WHOIS enrichment."
rule_id = "mr_209a5ab1-a0ea-473c-bfae-7beb67673e99"
rule_name = "WHOIS Recently Created Domain Access"
type = "alert"
tags = "whois"
data_source = "zscalar"
severity = "Info"
priority = "Info"
events:
($access.metadata.event_type = "NETWORK_HTTP" or $access.metadata.event_type = "NETWORK_CONNECTION")
// join access event to entity graph to use WHOIS data
$access.target.hostname = $domain
// Whois domains provided by GCTI Feed
$whois.graph.entity.domain.name = $domain
$whois.graph.metadata.entity_type = "DOMAIN_NAME"
$whois.graph.metadata.vendor_name = "WHOIS"
$whois.graph.metadata.product_name = "WHOISXMLAPI Simple Whois"
$whois.graph.metadata.source_type = "GLOBAL_CONTEXT"
$whois.graph.entity.domain.creation_time.seconds > 0
// domain was created in the last 30 days
2592000 > timestamp.current_seconds() - $whois.graph.entity.domain.creation_time.seconds
match:
$domain over 1h
outcome:
$risk_score = 20
$event_count = count_distinct($access.metadata.id)
//added to populate alert graph with additional context
$principal_hostname = array_distinct($access.principal.hostname)
// Commented out target.hostname because it is already represented in graph as match variable. If match changes, can uncomment to add to results
//$target_hostname = array_distinct($access.target.hostname)
$principal_process_pid = array_distinct($access.principal.process.pid)
$principal_process_command_line = array_distinct($access.principal.process.command_line)
$principal_process_file_sha256 = array_distinct($access.principal.process.file.sha256)
$principal_process_file_full_path = array_distinct($access.principal.process.file.full_path)
$principal_process_product_specific_process_id = array_distinct($access.principal.process.product_specific_process_id)
$principal_process_parent_process_product_specific_process_id = array_distinct($access.principal.process.parent_process.product_specific_process_id)
$target_process_pid = array_distinct($access.target.process.pid)
$target_process_command_line = array_distinct($access.target.process.command_line)
$target_process_file_sha256 = array_distinct($access.target.process.file.sha256)
$target_process_file_full_path = array_distinct($access.target.process.file.full_path)
$target_process_product_specific_process_id = array_distinct($access.target.process.product_specific_process_id)
$target_process_parent_process_product_specific_process_id = array_distinct($access.target.process.parent_process.product_specific_process_id)
$principal_user_userid = array_distinct($access.principal.user.userid)
$target_user_userid = array_distinct($access.target.user.userid)
$target_url = array_distinct($access.target.url)
condition:
$access and $whois
}
YARA-L rule structure
Condition
Fires when at least one $access event in the 1h window and $whois matches entity context.
Events
$access
$whois
graph.metadata.entity_type = "DOMAIN_NAME"graph.metadata.vendor_name = "WHOIS"graph.metadata.product_name = "WHOISXMLAPI Simple Whois"graph.metadata.source_type = "GLOBAL_CONTEXT"graph.entity.domain.creation_time.seconds > "0"timestamp.current_seconds() time_arithmetic "graph.entity.domain.creation_time.seconds" or "2592000"
Match and correlation
Outcome
Outcome variables add context to a detection. When the rule generates an alert, $risk_score is displayed with it.
| Field | Expression |
|---|---|
risk_score | 20 |
event_count | count_distinct($access.metadata.id) |
principal_hostname | array_distinct($access.principal.hostname) |
principal_process_pid | array_distinct($access.principal.process.pid) |
principal_process_command_line | array_distinct($access.principal.process.command_line) |
principal_process_file_sha256 | array_distinct($access.principal.process.file.sha256) |
principal_process_file_full_path | array_distinct($access.principal.process.file.full_path) |
principal_process_product_specific_process_id | array_distinct($access.principal.process.product_specific_process_id) |
principal_process_parent_process_product_specific_process_id | array_distinct($access.principal.process.parent_process.product_specific_process_id) |
target_process_pid | array_distinct($access.target.process.pid) |
target_process_command_line | array_distinct($access.target.process.command_line) |
target_process_file_sha256 | array_distinct($access.target.process.file.sha256) |
target_process_file_full_path | array_distinct($access.target.process.file.full_path) |
target_process_product_specific_process_id | array_distinct($access.target.process.product_specific_process_id) |
target_process_parent_process_product_specific_process_id | array_distinct($access.target.process.parent_process.product_specific_process_id) |
principal_user_userid | array_distinct($access.principal.user.userid) |
target_user_userid | array_distinct($access.target.user.userid) |
target_url | array_distinct($access.target.url) |