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# EKM policy evaluations =======================================================
# Controls: EKM-001 through EKM-008
package controls.aws.ekm
import data.common.exemptions as exemptions
import data.common.outputs as outputs
import data.common.policydoc as policydoc
# EKM-001 — Enable Rotation for KMS Customer Managed Keys ---------------------
deny contains msg if {
policy_id := "ICP-TF-AWS-EKM-001"
some _, rc in input.resource_changes
rc.type == "aws_kms_key"
rc.change.actions[_] in ["create", "update"]
rc.change.after.customer_master_key_spec == "SYMMETRIC_DEFAULT"
rc.change.after.enable_key_rotation != true
meta := data.policies[policy_id]
meta.status == "active"
not exemptions.policy_exemption(policy_id)
not exemptions.severity_exemption(meta.severity)
msg := outputs.violation(
policy_id, meta,
sprintf("KMS key '%s' does not have automatic rotation enabled", [rc.name]),
)
}
# EKM-002 — Enforce Minimum KMS Key Deletion Window ---------------------------
deny contains msg if {
policy_id := "ICP-TF-AWS-EKM-002"
some _, rc in input.resource_changes
rc.type == "aws_kms_key"
rc.change.actions[_] in ["create", "update"]
window := rc.change.after.deletion_window_in_days
window != null
window < 30
meta := data.policies[policy_id]
meta.status == "active"
not exemptions.policy_exemption(policy_id)
not exemptions.severity_exemption(meta.severity)
msg := outputs.violation(
policy_id, meta,
sprintf("KMS key '%s' has deletion window of %d days (minimum 30)", [rc.name, window]),
)
}
# EKM-003 — Prohibit kms:Decrypt on All KMS Keys ------------------------------
deny contains msg if {
policy_id := "ICP-TF-AWS-EKM-003"
some _, rc in input.resource_changes
rc.type in {"aws_iam_policy", "aws_iam_role_policy"}
rc.change.actions[_] in ["create", "update"]
doc := json.unmarshal(rc.change.after.policy)
some stmt in doc.Statement
stmt.Effect == "Allow"
some action in policydoc.as_list(stmt.Action)
_broad_kms_action(action)
some resource in policydoc.as_list(stmt.Resource)
resource == "*"
meta := data.policies[policy_id]
meta.status == "active"
not exemptions.policy_exemption(policy_id)
not exemptions.severity_exemption(meta.severity)
msg := outputs.violation(
policy_id, meta,
sprintf("'%s.%s' grants '%s' on all KMS keys via Resource *", [rc.type, rc.name, action]),
)
}
_broad_kms_action(a) if a == "kms:*"
_broad_kms_action(a) if a == "kms:Decrypt"
_broad_kms_action(a) if a == "kms:ReEncryptFrom"
# EKM-004 — Require Conditions on KMS Key Policies Granting Full Access to Root
# Advisory: emits to warn, not deny
warn contains msg if {
policy_id := "ICP-TF-AWS-EKM-004"
some _, rc in input.resource_changes
rc.type in {"aws_kms_key", "aws_kms_key_policy"}
rc.change.actions[_] in ["create", "update"]
policy_raw := _kms_policy_raw(rc)
doc := json.unmarshal(policy_raw)
some stmt in doc.Statement
stmt.Effect == "Allow"
some action in policydoc.as_list(stmt.Action)
action == "kms:*"
some principal in policydoc.as_list(stmt.Principal.AWS)
endswith(principal, ":root")
not stmt.Condition
meta := data.policies[policy_id]
meta.status == "active"
not exemptions.policy_exemption(policy_id)
not exemptions.severity_exemption(meta.severity)
msg := outputs.violation(
policy_id, meta,
sprintf("KMS key '%s' grants kms:* to root principal without a Condition", [rc.name]),
)
}
_kms_policy_raw(rc) := rc.change.after.policy if rc.type == "aws_kms_key"
_kms_policy_raw(rc) := rc.change.after.policy if rc.type == "aws_kms_key_policy"
# EKM-005 — Enforce SSE-KMS on S3 Buckets -------------------------------------
deny contains msg if {
policy_id := "ICP-TF-AWS-EKM-005"
some _, rc in input.resource_changes
rc.type == "aws_s3_bucket_server_side_encryption_configuration"
rc.change.actions[_] in ["create", "update"]
some rule in rc.change.after.rule
some sse in rule.apply_server_side_encryption_by_default
not _sse_kms_with_cmk(sse)
meta := data.policies[policy_id]
meta.status == "active"
not exemptions.policy_exemption(policy_id)
not exemptions.severity_exemption(meta.severity)
msg := outputs.violation(
policy_id, meta,
sprintf("S3 encryption configuration '%s' does not use SSE-KMS with a CMK", [rc.name]),
)
}
_sse_kms_with_cmk(sse) if {
sse.sse_algorithm == "aws:kms"
sse.kms_master_key_id != null
sse.kms_master_key_id != ""
}
# EKM-006 — Enable EBS Default Encryption per Region --------------------------
deny contains msg if {
some policy_id in {"ICP-TF-AWS-EKM-006", "ICP-TF-AWS-CMP-010", "ICP-TF-AWS-GAC-006"}
some _, rc in input.resource_changes
rc.type == "aws_ebs_encryption_by_default"
rc.change.actions[_] in ["create", "update"]
rc.change.after.enabled != true
meta := data.policies[policy_id]
meta.status == "active"
not exemptions.policy_exemption(policy_id)
not exemptions.severity_exemption(meta.severity)
msg := outputs.violation(
policy_id, meta,
sprintf("EBS default encryption '%s' is not enabled", [rc.name]),
)
}
deny contains msg if {
policy_id := "ICP-TF-AWS-EKM-006"
some _, rc in input.resource_changes
rc.type == "aws_ebs_default_kms_key"
rc.change.actions[_] in ["create", "update"]
not _has_cmk(rc.change.after)
meta := data.policies[policy_id]
meta.status == "active"
not exemptions.policy_exemption(policy_id)
not exemptions.severity_exemption(meta.severity)
msg := outputs.violation(
policy_id, meta,
sprintf("EBS default KMS key '%s' is not set to a customer-managed key", [rc.name]),
)
}
_has_cmk(after) if {
after.key_arn != null
after.key_arn != ""
}
# EKM-007 — Configure Rotation for Secrets Manager Secrets --------------------
deny contains msg if {
policy_id := "ICP-TF-AWS-EKM-007"
some _, rc in input.resource_changes
rc.type == "aws_secretsmanager_secret"
rc.change.actions[_] in ["create", "update"]
not _secret_has_rotation(rc)
meta := data.policies[policy_id]
meta.status == "active"
not exemptions.policy_exemption(policy_id)
not exemptions.severity_exemption(meta.severity)
msg := outputs.violation(
policy_id, meta,
sprintf("Secrets Manager secret '%s' has no rotation configured", [rc.name]),
)
}
_secret_has_rotation(rc) if {
some _, other in input.resource_changes
other.type == "aws_secretsmanager_secret_rotation"
other.change.actions[_] in ["create", "update"]
other.change.after.secret_id == rc.change.after.name
other.change.after.rotation_lambda_arn != null
other.change.after.rotation_rules[_].automatically_after_days <= 90
}
# EKM-008 — Enforce Minimum Key Length for ACM RSA Certificates ---------------
deny contains msg if {
policy_id := "ICP-TF-AWS-EKM-008"
some _, rc in input.resource_changes
rc.type == "aws_acm_certificate"
rc.change.actions[_] in ["create", "update"]
_weak_rsa_key(rc.change.after.key_algorithm)
meta := data.policies[policy_id]
meta.status == "active"
not exemptions.policy_exemption(policy_id)
not exemptions.severity_exemption(meta.severity)
msg := outputs.violation(
policy_id, meta,
sprintf("ACM certificate '%s' uses weak key algorithm '%s' (minimum RSA_2048)", [rc.name, rc.change.after.key_algorithm]),
)
}
_weak_rsa_key(algo) if algo == "RSA_1024"
_weak_rsa_key(algo) if algo == "RSA_512"
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