Create Rule

create-rule

Cartography rules detect attack surfaces, security gaps, and compliance issues across the graph. Rules are composed of one or more Facts (Cypher queries) and a Finding output model (Pydantic).

Architecture

Rule (e.g., "database-exposed")
  ├─ Fact (e.g., "aws-rds-public")
  ├─ Fact (e.g., "azure-sql-public")
  └─ Fact (e.g., "gcp-cloudsql-public")

• Rule — represents a security issue / attack surface.
• Fact — single Cypher query that gathers evidence.
• Finding — Pydantic model defining the result row structure.

Critical rules

1. cypher_query aliases must match Finding field names exactly. Use RETURN x.id AS id, x.name AS name.
2. cypher_visual_query returns nodes, not properties — used for graph viz.
3. All Finding fields are | None with default None. The source field is auto-populated.
4. source and extra are reserved. Never alias them in a cypher_query; use ontology_source for _ont_source.
5. The cypher_query must match the declared asset_label. MATCH (k:APIKey) WHERE k:OpenAIApiKey ..., not MATCH (k) WHERE k:OpenAIApiKey ..., so the rows returned cannot diverge from the asset claimed.
6. Compliance metadata uses frameworks=, not tags. Keep tags for categories only (iam, credentials, stride:*).
7. Rule IDs and names describe the Cartography security detection, not the compliance control. Put framework scope, requirement/control id, and external control title in frameworks=.

Instructions

Step 1 — Imports

from cartography.rules.spec.model import (
    Fact,
    Finding,
    Framework,
    Maturity,
    Module,
    Rule,
    RuleReference,
)

Step 2 — Author Facts

A Fact is a Cypher query that detects one specific condition:

_aws_public_databases = Fact(
    id="aws-rds-public",
    name="Publicly accessible AWS RDS instances",
    description="AWS RDS databases exposed to the internet",
    cypher_query="""
    MATCH (db:AWSRDSInstance)
    WHERE db.publicly_accessible = true
    RETURN db.id AS id, db.db_instance_identifier AS name, db.region AS region
    """,
    cypher_visual_query="""
    MATCH (db:AWSRDSInstance)
    WHERE db.publicly_accessible = true
    RETURN db
    """,
    cypher_count_query="""
    MATCH (db:AWSRDSInstance)
    RETURN COUNT(db) AS count
    """,
    identity_fields=("id",),
    module=Module.AWS,
    maturity=Maturity.STABLE,
)

Fact fields:

Step 3 — Define the Finding output model

class DatabaseExposedOutput(Finding):
    """Output model for publicly exposed databases."""
    name: str | None = None    # human-readable label first: used as the finding title
    id: str | None = None
    region: str | None = None

• Inherit from Finding.
• Field names must match cypher_query aliases exactly.
• All fields are | None with default None.
• The source field is auto-populated with the module name and is reserved: do not return a source column. Alias the per-row ontology provider ontology_source and declare it on the model.
• Declare a human-readable label as the first field. Downstream consumers derive the finding's title from the first non-empty field in declaration order, so leading with an opaque id, ARN, URI, digest, region, or boolean produces an unreadable title. If the node has no natural name, alias one in the cypher_query (e.g. coalesce(n.friendly_name, n.short_id) AS name, or an AWS Name tag) and declare it first. This is independent of identity_fields/asset_id_field and of RETURN order. See "Display field order (finding title)" in docs/root/usage/rules.md.
• Set identity_fields on the Fact (required) to the subset of these fields that forms the finding's stable logical identity, excluding volatile context (*_count, days_*, last_used*, *_date, posture booleans, aggregate lists) so downstream lifecycle tracking does not treat a changed metric as a new finding. See "Finding identity vs. display fields" in docs/root/usage/rules.md.

Step 4 — Compose the Rule

database_exposed = Rule(
    id="database-exposed",
    name="Publicly Accessible Databases",
    description="Detects databases exposed to the internet across cloud providers",
    output_model=DatabaseExposedOutput,
    tags=("infrastructure", "attack_surface", "database"),
    facts=(_aws_public_databases, _azure_public_databases, _gcp_cloudsql_public),
    version="1.0.0",
)

Rule fields:

Step 5 — Maturity, versioning, tagging

• Maturity.EXPERIMENTAL — new, may have bugs / perf issues. Use for testing detection capabilities.
• Maturity.STABLE — production-ready, well-tested, optimized.

Versioning follows semver (0.1.0 initial, 0.2.0 add facts, 0.2.1 bug fix, 1.0.0 production-ready).

Tag categories:

• Category: infrastructure, identity, data, network, compute.
• Type: attack_surface, misconfiguration, compliance, vulnerability.
• Provider: aws, azure, gcp, github, okta.
• Threat model: stride:spoofing, stride:tampering, stride:repudiation, stride:information_disclosure, stride:denial_of_service, stride:elevation_of_privilege.

Step 6 — Register the Rule

In cartography/rules/data/rules/__init__.py:

from cartography.rules.data.rules.my_security_rule import my_security_rule

RULES = {
    # ... existing rules
    my_security_rule.id: my_security_rule,
}

Step 7 — Test it

cartography-rules list my_security_rule
cartography-rules run my_security_rule
cartography-rules run my_security_rule --output json
cartography-rules run my_security_rule --no-experimental

Compliance frameworks

For CIS, NIST, SOC2, etc., attach a Framework object or framework helper instead of polluting tags:

from cartography.rules.data.frameworks.cis import cis_aws

my_rule = Rule(
    id="aws_access_keys_not_rotated",
    name="Access Keys Not Rotated",
    # ...
    tags=("iam", "credentials", "stride:spoofing"),  # category tags only
    frameworks=(
        cis_aws("1.14"),
    ),
)

Compliance-style tags like cis:1.14, cis:aws-5.0 must NOT live in tags. CLI users filter via --framework CIS, --framework CIS:aws, --framework CIS:aws:5.0.

For framework helpers with known canonical controls, the helper fills Framework.control_title. For custom mappings, set Framework(control_title="...") to the external framework control or requirement title. Keep Rule.name as reusable Cartography security copy. Many Cartography rules may map to the same framework control.

Framework helpers encode the one active revision Cartography supports for each benchmark scope today. If Cartography needs to report against multiple benchmark revisions later, add version-aware helpers or explicit framework objects instead of mixing revisions in one helper.

For deeper framework guidance, including CIS benchmark conventions (rule names, IDs, file naming, headers, references), see references/compliance-frameworks.md and references/cis-conventions.md.

Cross-provider rules

Group facts from different cloud providers under one rule. Each fact's cypher_query should include the provider in the result so the Finding has it:

_aws_unencrypted_storage = Fact(
    id="aws-s3-unencrypted",
    cypher_query="""
    MATCH (b:AWSS3Bucket) WHERE b.default_encryption IS NULL
    RETURN b.id AS id, b.name AS name, 'aws' AS provider
    """,
    # ...
    module=Module.AWS,
    maturity=Maturity.STABLE,
)


_azure_unencrypted_storage = Fact(
    id="azure-storage-unencrypted",
    cypher_query="""
    MATCH (s:AzureStorageAccount) WHERE s.encryption_enabled = false
    RETURN s.id AS id, s.name AS name, 'azure' AS provider
    """,
    module=Module.AZURE,
    maturity=Maturity.STABLE,
)


class UnencryptedStorageOutput(Finding):
    id: str | None = None
    name: str | None = None
    provider: str | None = None


unencrypted_storage = Rule(
    id="unencrypted_storage",
    name="Unencrypted Cloud Storage",
    description="Detects unencrypted storage across cloud providers",
    output_model=UnencryptedStorageOutput,
    tags=("data", "encryption", "compliance"),
    facts=(_aws_unencrypted_storage, _azure_unencrypted_storage),
    version="1.0.0",
)

Using the ontology

Leverage semantic labels (e.g. UserAccount) and _ont_* properties for cross-module detection:

_unmanaged_accounts = Fact(
    id="unmanaged-accounts-ontology",
    name="User Accounts Not Linked to Identity",
    description="Detects user accounts without a corresponding User identity",
    cypher_query="""
    MATCH (ua:UserAccount)
    WHERE NOT (ua)<-[:HAS_ACCOUNT]-(:User)
    RETURN ua.id AS id, ua._ont_email AS email, ua._ont_source AS ontology_source
    """,
    cypher_visual_query="""
    MATCH (ua:UserAccount)
    WHERE NOT (ua)<-[:HAS_ACCOUNT]-(:User)
    RETURN ua
    """,
    cypher_count_query="""
    MATCH (ua:UserAccount)
    RETURN COUNT(ua) AS count
    """,
    asset_label="UserAccount",
    asset_id_field="id",
    identity_fields=("ontology_source", "id"),
    module=Module.CROSS_CLOUD,
    maturity=Maturity.STABLE,
)

For semantic-label setup, see the enrich-ontology skill.

References (load on demand)

• references/compliance-frameworks.md — Framework field reference, CLI filtering, Rule.has_framework() checks.
• references/ontology-in-rules.md — using UserAccount / Tenant / Database labels and _ont_* props in rule queries.
• references/cis-conventions.md — CIS rule naming, IDs, file layout, headers, references, complete CIS example.