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[Rule Tuning] Update rules using NPC integration and non-ECS fields #3194

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[Rule Tuning] Update rules using NPC integration and non-ECS fields #3194

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e1abde7
[Rule Tuning] Update rules using NPC integration and non-ECS fields
brokensound77 Oct 16, 2023
4abb55a
Merge branch 'main' into update-npc-integration-ecs-fields
brokensound77 Oct 16, 2023
446e4d4
Merge branch 'main' into update-npc-integration-ecs-fields
brokensound77 Oct 16, 2023
e5f176d
switch from headers.content-type to mime_type
brokensound77 Oct 16, 2023
ce26596
Merge branch 'main' into update-npc-integration-ecs-fields
brokensound77 Nov 20, 2023
956d77b
update field to network_traffic.http.request.headers.authorization:*
brokensound77 Nov 21, 2023
d478741
update network_traffic integration schema
brokensound77 Dec 15, 2023
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16 changes: 9 additions & 7 deletions rules/network/command_and_control_cobalt_strike_beacon.toml
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Original file line number Diff line number Diff line change
Expand Up @@ -2,8 +2,8 @@
creation_date = "2020/07/06"
integration = ["network_traffic"]
maturity = "production"
min_stack_comments = "New fields added: required_fields, related_integrations, setup"
min_stack_version = "8.3.0"
min_stack_comments = "Network integration fields updated for ECS compatibility (type -> network.protocol)"
min_stack_version = "8.10.0"
updated_date = "2023/10/16"

[rule]
Expand All @@ -21,7 +21,7 @@ false_positives = [
]
from = "now-9m"
index = ["packetbeat-*", "auditbeat-*", "filebeat-*", "logs-network_traffic.*"]
language = "lucene"
language = "eql"
license = "Elastic License v2"
name = "Cobalt Strike Command and Control Beacon"
note = """## Threat intel
Expand All @@ -37,12 +37,14 @@ rule_id = "cf53f532-9cc9-445a-9ae7-fced307ec53c"
severity = "high"
tags = ["Use Case: Threat Detection", "Tactic: Command and Control", "Domain: Endpoint"]
timestamp_override = "event.ingested"
type = "query"
type = "eql"

query = '''
((event.category: (network OR network_traffic) AND type: (tls OR http))
OR event.dataset: (network_traffic.tls OR network_traffic.http)
) AND destination.domain:/[a-z]{3}.stage.[0-9]{8}\..*/
any where
((event.category in ("network", "network_traffic") and network.protocol in ("tls", "http")) or
event.dataset in ("network_traffic.tls", "network_traffic.http")
) and
destination.domain regex~ """[a-z]{3}.stage.[0-9]{8}\..*"""
'''


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17 changes: 10 additions & 7 deletions rules/network/command_and_control_fin7_c2_behavior.toml
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Original file line number Diff line number Diff line change
Expand Up @@ -2,8 +2,8 @@
creation_date = "2020/07/06"
integration = ["network_traffic"]
maturity = "production"
min_stack_comments = "New fields added: required_fields, related_integrations, setup"
min_stack_version = "8.3.0"
min_stack_comments = "Network integration fields updated for ECS compatibility (type -> network.protocol)"
min_stack_version = "8.10.0"
updated_date = "2023/10/16"

[rule]
Expand All @@ -20,7 +20,7 @@ false_positives = [
]
from = "now-9m"
index = ["packetbeat-*", "auditbeat-*", "filebeat-*", "logs-network_traffic.*"]
language = "lucene"
language = "eql"
license = "Elastic License v2"
name = "Possible FIN7 DGA Command and Control Behavior"
note = """## Triage and analysis
Expand All @@ -34,12 +34,15 @@ rule_id = "4a4e23cf-78a2-449c-bac3-701924c269d3"
severity = "high"
tags = ["Use Case: Threat Detection", "Tactic: Command and Control", "Domain: Endpoint"]
timestamp_override = "event.ingested"
type = "query"
type = "eql"

query = '''
(event.dataset: (network_traffic.tls OR network_traffic.http) or
(event.category: (network OR network_traffic) AND type: (tls OR http) AND network.transport: tcp)) AND
destination.domain:/[a-zA-Z]{4,5}\.(pw|us|club|info|site|top)/ AND NOT destination.domain:zoom.us
any where
((event.category in ("network", "network_traffic") and network.protocol in ("tls", "http") and network.transport == "tcp") or
event.dataset in ("network_traffic.tls", "network_traffic.http")
) and
destination.domain regex~ """[a-zA-Z]{4,5}\.(pw|us|club|info|site|top)""" and
not destination.domain : "zoom.us"
'''


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13 changes: 7 additions & 6 deletions rules/network/initial_access_unsecure_elasticsearch_node.toml
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Original file line number Diff line number Diff line change
Expand Up @@ -2,8 +2,8 @@
creation_date = "2020/08/11"
integration = ["network_traffic"]
maturity = "production"
min_stack_comments = "New fields added: required_fields, related_integrations, setup"
min_stack_version = "8.3.0"
min_stack_comments = "Network integration fields updated for ECS compatibility (status -> http.response.status_phrase)"
min_stack_version = "8.10.0"
updated_date = "2023/10/16"

[rule]
Expand All @@ -20,7 +20,7 @@ false_positives = [
]
from = "now-9m"
index = ["packetbeat-*", "logs-network_traffic.*"]
language = "lucene"
language = "kuery"
license = "Elastic License v2"
name = "Inbound Connection to an Unsecure Elasticsearch Node"
note = """## Setup
Expand All @@ -38,9 +38,10 @@ timestamp_override = "event.ingested"
type = "query"

query = '''
(event.dataset: network_traffic.http OR (event.category: network_traffic AND network.protocol: http)) AND
status:OK AND destination.port:9200 AND network.direction:inbound AND NOT http.response.headers.content-type:"image/x-icon" AND NOT
_exists_:http.request.headers.authorization
(event.dataset:network_traffic.http or (event.category:network_traffic and network.protocol:http)) and
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Because our query validation for integrations occurs separately from the base query validation (ECS + beats diff), there is a conflict where a rule cannot satisfy both validations. This is the first rule with an integration-specific field (that I am aware of), which results in it

  • failing base query validation because the fields do not exist in ECS or beats
  • passing integration validation

As a test, even if we added the fields to non-ecs-schema (as a bad hack), the rule still fails because the ECS/beats field is not known to the integration

Integration only fields:

  • http.response.status_phrase
  • network_traffic.http.request.headers.authorization

Unknown to integration

  • http.request.headers.authorization
  • status

With the existing process, the only way to rectify this is to split the rule, however that is not sustainable. We need to review this for potential refactor.

attempted cross-compatible query, which fails based on the above

(event.dataset:network_traffic.http or (event.category:network_traffic and network.protocol:http)) and
    (status:ok or http.response.status_phrase:ok) and
    destination.port:9200 and network.direction:inbound and
    not http.response.mime_type:"image/x-icon" and
    not (network_traffic.http.request.headers.authorization:* or http.request.headers.authorization:*)

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Reference the description above for further details and coexisting bugs

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Thanks Justin for bringing this to our attention! I will have to dive a bit deeper, but I recall that we specifically allow it to validate ECS+beats OR integrations.

detection-rules/detection_rules/rule_validators.py

Lines 48 to 70 in a6c5cfc

def validate(self, data: QueryRuleData, meta: RuleMeta) -> None:
"""Validate the query, called from the parent which contains [metadata] information."""
if meta.query_schema_validation is False or meta.maturity == "deprecated":
# syntax only, which is done via self.ast
return
if isinstance(data, QueryRuleData) and data.language != 'lucene':
packages_manifest = load_integrations_manifests()
package_integrations = TOMLRuleContents.get_packaged_integrations(data, meta, packages_manifest)
validation_checks = {"stack": None, "integrations": None}
# validate the query against fields within beats
validation_checks["stack"] = self.validate_stack_combos(data, meta)
if package_integrations:
# validate the query against related integration fields
validation_checks["integrations"] = self.validate_integration(data, meta, package_integrations)
if (validation_checks["stack"] and not package_integrations):
raise validation_checks["stack"]
if (validation_checks["stack"] and validation_checks["integrations"]):
raise ValueError(f"Error in both stack and integrations checks: {validation_checks}")

If you review this code, validation_checks holds the state of ECS+Beats OR Integration validation checks. If both fail, then yes the rule should be reviewed because neither the integration's schema nor ECS, Non-ECS or Beats have the fields or the query is incorrect.

http.response.status_phrase:ok and destination.port:9200 and network.direction:inbound and
not http.response.headers.content-type:"image/x-icon" and
not http.request.headers.authorization:*
'''


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10 changes: 5 additions & 5 deletions rules/network/lateral_movement_dns_server_overflow.toml
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Original file line number Diff line number Diff line change
Expand Up @@ -2,9 +2,9 @@
creation_date = "2020/07/16"
integration = ["network_traffic"]
maturity = "production"
min_stack_comments = "New fields added: required_fields, related_integrations, setup"
min_stack_version = "8.3.0"
updated_date = "2023/08/01"
min_stack_comments = "Network integration fields updated for ECS compatibility (type -> network.protocol)"
min_stack_version = "8.10.0"
updated_date = "2023/10/16"

[rule]
author = ["Elastic"]
Expand Down Expand Up @@ -74,8 +74,8 @@ timestamp_override = "event.ingested"
type = "query"

query = '''
(event.dataset: network_traffic.dns or (event.category: (network or network_traffic) and destination.port: 53)) and
(event.dataset:zeek.dns or type:dns or event.type:connection) and network.bytes > 60000
(event.dataset:network_traffic.dns or (event.category:(network or network_traffic) and destination.port:53)) and
(event.dataset:zeek.dns or network.protocol:dns or event.type:connection) and network.bytes > 60000
'''


Expand Down