feat(networkfirewall): add new check networkfirewall_policy_default_action_fragmented_packets (#5244)

Co-authored-by: Sergio Garcia <38561120+sergargar@users.noreply.github.com>
2026-07-23 20:42:02 +00:00 · 2024-10-04 17:41:26 +02:00
parent df10253056
commit f2301d5ed6
5 changed files with 254 additions and 3 deletions
@@ -0,0 +1,32 @@
+{
+  "Provider": "aws",
+  "CheckID": "networkfirewall_policy_default_action_fragmented_packets",
+  "CheckTitle": "Default action for fragmented packets is set to drop or forward.",
+  "CheckType": [
+    "Software and Configuration Checks/Industry and Regulatory Standards/NIST 800-53 Controls"
+  ],
+  "ServiceName": "network-firewall",
+  "SubServiceName": "",
+  "ResourceIdTemplate": "arn:partition:network-firewall::account-id:firewall/firewall-name",
+  "Severity": "medium",
+  "ResourceType": "AwsNetworkFirewallFirewall",
+  "Description": "NetorwFirewall firewall policy default action for fragmented packets is set to drop or forward.",
+  "Risk": "If the default action for fragmented packets is set to 'Pass', unintended or potentially malicious traffic may bypass filtering, exposing the network to security threats.",
+  "RelatedUrl": "https://docs.aws.amazon.com/network-firewall/latest/developerguide/stateless-default-actions.html",
+  "Remediation": {
+    "Code": {
+      "CLI": "aws network-firewall update-firewall-policy --firewall-policy-arn <your-firewall-policy-arn> --stateless-default-actions aws:drop",
+      "NativeIaC": "",
+      "Other": "https://docs.aws.amazon.com/securityhub/latest/userguide/networkfirewall-controls.html#networkfirewall-5",
+      "Terraform": ""
+    },
+    "Recommendation": {
+      "Text": "Update the firewall policy to ensure fragmented packets are either dropped or forwarded to stateful rule groups for additional filtering, reducing the risk of unwanted traffic entering the network.",
+      "Url": "https://docs.aws.amazon.com/network-firewall/latest/developerguide/firewall-policy-updating.html"
+    }
+  },
+  "Categories": [],
+  "DependsOn": [],
+  "RelatedTo": [],
+  "Notes": ""
+}
@@ -0,0 +1,28 @@
+from prowler.lib.check.models import Check, Check_Report_AWS
+from prowler.providers.aws.services.networkfirewall.networkfirewall_client import (
+    networkfirewall_client,
+)
+
+
+class networkfirewall_policy_default_action_fragmented_packets(Check):
+    def execute(self):
+        findings = []
+        for arn, firewall in networkfirewall_client.network_firewalls.items():
+            report = Check_Report_AWS(self.metadata())
+            report.region = firewall.region
+            report.resource_id = firewall.name
+            report.resource_arn = arn
+            report.resource_tags = firewall.tags
+            report.status = "FAIL"
+            report.status_extended = f"Network Firewall {firewall.name} policy does not drop or forward fragmented packets by default."
+
+            if (
+                "aws:drop" in firewall.default_stateless_frag_actions
+                or "aws:forward_to_sfe" in firewall.default_stateless_frag_actions
+            ):
+                report.status = "PASS"
+                report.status_extended = f"Network Firewall {firewall.name} policy does drop or forward fragmented packets by default."
+
+            findings.append(report)
+
+        return findings
@@ -37,9 +37,8 @@ class NetworkFirewall(AWSService):
                            network_firewall["FirewallArn"], self.audit_resources
                        )
                    ):
-                        self.network_firewalls[
-                            network_firewall.get("FirewallArn", "")
-                        ] = Firewall(
+                        arn = network_firewall.get("FirewallArn", "")
+                        self.network_firewalls[arn] = Firewall(
                            arn=network_firewall.get("FirewallArn"),
                            region=regional_client.region,
                            name=network_firewall.get("FirewallName"),
@@ -95,6 +94,9 @@ class NetworkFirewall(AWSService):
                group.get("ResourceArn", "")
                for group in firewall_policy.get("StatefulRuleGroupReferences", [])
            ]
+            network_firewall.default_stateless_frag_actions = firewall_policy.get(
+                "StatelessFragmentDefaultActions", []
+            )
        except Exception as error:
            logger.error(
                f"{error.__class__.__name__}:{error.__traceback__.tb_lineno} -- {error}"
@@ -184,6 +186,7 @@ class Firewall(BaseModel):
    tags: list = []
    encryption_type: str = None
    deletion_protection: bool = False
+    default_stateless_frag_actions: list = []
    subnet_mappings: list[Subnet] = []
    logging_configuration: Optional[list[LoggingConfiguration]]
    stateless_rule_groups: list[str] = []
@@ -0,0 +1,188 @@
+from unittest import mock
+
+from prowler.providers.aws.services.networkfirewall.networkfirewall_service import (
+    Firewall,
+)
+from tests.providers.aws.utils import AWS_REGION_US_EAST_1, set_mocked_aws_provider
+
+FIREWALL_ARN = "arn:aws:network-firewall:us-east-1:123456789012:firewall/my-firewall"
+FIREWALL_NAME = "my-firewall"
+VPC_ID_PROTECTED = "vpc-12345678901234567"
+VPC_ID_UNPROTECTED = "vpc-12345678901234568"
+POLICY_ARN = "arn:aws:network-firewall:us-east-1:123456789012:firewall-policy/my-policy"
+
+
+class Test_networkfirewall_policy_default_action_fragmented_packets:
+    def test_no_networkfirewall(self):
+        networkfirewall_client = mock.MagicMock
+        networkfirewall_client.provider = set_mocked_aws_provider(
+            [AWS_REGION_US_EAST_1]
+        )
+        networkfirewall_client.region = AWS_REGION_US_EAST_1
+        networkfirewall_client.network_firewalls = {}
+
+        aws_provider = set_mocked_aws_provider([AWS_REGION_US_EAST_1])
+
+        with mock.patch(
+            "prowler.providers.common.provider.Provider.get_global_provider",
+            return_value=aws_provider,
+        ):
+            with mock.patch(
+                "prowler.providers.aws.services.networkfirewall.networkfirewall_policy_default_action_fragmented_packets.networkfirewall_policy_default_action_fragmented_packets.networkfirewall_client",
+                new=networkfirewall_client,
+            ):
+                # Test Check
+                from prowler.providers.aws.services.networkfirewall.networkfirewall_policy_default_action_fragmented_packets.networkfirewall_policy_default_action_fragmented_packets import (
+                    networkfirewall_policy_default_action_fragmented_packets,
+                )
+
+                check = networkfirewall_policy_default_action_fragmented_packets()
+                result = check.execute()
+
+                assert len(result) == 0
+
+    def test_networkfirewall_default_stateless_action_drop(self):
+        networkfirewall_client = mock.MagicMock
+        networkfirewall_client.provider = set_mocked_aws_provider(
+            [AWS_REGION_US_EAST_1]
+        )
+        networkfirewall_client.region = AWS_REGION_US_EAST_1
+        networkfirewall_client.network_firewalls = {
+            FIREWALL_ARN: Firewall(
+                arn=FIREWALL_ARN,
+                name=FIREWALL_NAME,
+                region=AWS_REGION_US_EAST_1,
+                policy_arn=POLICY_ARN,
+                vpc_id=VPC_ID_PROTECTED,
+                tags=[],
+                encryption_type="CUSTOMER_KMS",
+                deletion_protection=False,
+                default_stateless_frag_actions=["aws:drop"],
+            )
+        }
+        aws_provider = set_mocked_aws_provider([AWS_REGION_US_EAST_1])
+
+        with mock.patch(
+            "prowler.providers.common.provider.Provider.get_global_provider",
+            return_value=aws_provider,
+        ):
+            with mock.patch(
+                "prowler.providers.aws.services.networkfirewall.networkfirewall_policy_default_action_fragmented_packets.networkfirewall_policy_default_action_fragmented_packets.networkfirewall_client",
+                new=networkfirewall_client,
+            ):
+                # Test Check
+                from prowler.providers.aws.services.networkfirewall.networkfirewall_policy_default_action_fragmented_packets.networkfirewall_policy_default_action_fragmented_packets import (
+                    networkfirewall_policy_default_action_fragmented_packets,
+                )
+
+                check = networkfirewall_policy_default_action_fragmented_packets()
+                result = check.execute()
+
+                assert len(result) == 1
+                assert result[0].status == "PASS"
+                assert (
+                    result[0].status_extended
+                    == f"Network Firewall {FIREWALL_NAME} policy does drop or forward fragmented packets by default."
+                )
+                assert result[0].region == AWS_REGION_US_EAST_1
+                assert result[0].resource_id == FIREWALL_NAME
+                assert result[0].resource_tags == []
+                assert result[0].resource_arn == FIREWALL_ARN
+
+    def test_networkfirewall_default_stateless_action_forward(self):
+        networkfirewall_client = mock.MagicMock
+        networkfirewall_client.provider = set_mocked_aws_provider(
+            [AWS_REGION_US_EAST_1]
+        )
+        networkfirewall_client.region = AWS_REGION_US_EAST_1
+        networkfirewall_client.network_firewalls = {
+            FIREWALL_ARN: Firewall(
+                arn=FIREWALL_ARN,
+                name=FIREWALL_NAME,
+                region=AWS_REGION_US_EAST_1,
+                policy_arn=POLICY_ARN,
+                vpc_id=VPC_ID_PROTECTED,
+                tags=[],
+                encryption_type="CUSTOMER_KMS",
+                deletion_protection=True,
+                default_stateless_frag_actions=["aws:forward_to_sfe"],
+            )
+        }
+
+        aws_provider = set_mocked_aws_provider([AWS_REGION_US_EAST_1])
+
+        with mock.patch(
+            "prowler.providers.common.provider.Provider.get_global_provider",
+            return_value=aws_provider,
+        ):
+            with mock.patch(
+                "prowler.providers.aws.services.networkfirewall.networkfirewall_policy_default_action_fragmented_packets.networkfirewall_policy_default_action_fragmented_packets.networkfirewall_client",
+                new=networkfirewall_client,
+            ):
+                # Test Check
+                from prowler.providers.aws.services.networkfirewall.networkfirewall_policy_default_action_fragmented_packets.networkfirewall_policy_default_action_fragmented_packets import (
+                    networkfirewall_policy_default_action_fragmented_packets,
+                )
+
+                check = networkfirewall_policy_default_action_fragmented_packets()
+                result = check.execute()
+
+                assert len(result) == 1
+                assert result[0].status == "PASS"
+                assert (
+                    result[0].status_extended
+                    == f"Network Firewall {FIREWALL_NAME} policy does drop or forward fragmented packets by default."
+                )
+                assert result[0].region == AWS_REGION_US_EAST_1
+                assert result[0].resource_id == FIREWALL_NAME
+                assert result[0].resource_tags == []
+                assert result[0].resource_arn == FIREWALL_ARN
+
+    def test_networkfirewall_default_stateless_action_pass(self):
+        networkfirewall_client = mock.MagicMock
+        networkfirewall_client.provider = set_mocked_aws_provider(
+            [AWS_REGION_US_EAST_1]
+        )
+        networkfirewall_client.region = AWS_REGION_US_EAST_1
+        networkfirewall_client.network_firewalls = {
+            FIREWALL_ARN: Firewall(
+                arn=FIREWALL_ARN,
+                name=FIREWALL_NAME,
+                region=AWS_REGION_US_EAST_1,
+                policy_arn=POLICY_ARN,
+                vpc_id=VPC_ID_PROTECTED,
+                tags=[],
+                encryption_type="CUSTOMER_KMS",
+                deletion_protection=True,
+                default_stateless_frag_actions=["aws:pass"],
+            )
+        }
+
+        aws_provider = set_mocked_aws_provider([AWS_REGION_US_EAST_1])
+
+        with mock.patch(
+            "prowler.providers.common.provider.Provider.get_global_provider",
+            return_value=aws_provider,
+        ):
+            with mock.patch(
+                "prowler.providers.aws.services.networkfirewall.networkfirewall_policy_default_action_fragmented_packets.networkfirewall_policy_default_action_fragmented_packets.networkfirewall_client",
+                new=networkfirewall_client,
+            ):
+                # Test Check
+                from prowler.providers.aws.services.networkfirewall.networkfirewall_policy_default_action_fragmented_packets.networkfirewall_policy_default_action_fragmented_packets import (
+                    networkfirewall_policy_default_action_fragmented_packets,
+                )
+
+                check = networkfirewall_policy_default_action_fragmented_packets()
+                result = check.execute()
+
+                assert len(result) == 1
+                assert result[0].status == "FAIL"
+                assert (
+                    result[0].status_extended
+                    == f"Network Firewall {FIREWALL_NAME} policy does not drop or forward fragmented packets by default."
+                )
+                assert result[0].region == AWS_REGION_US_EAST_1
+                assert result[0].resource_id == FIREWALL_NAME
+                assert result[0].resource_tags == []
+                assert result[0].resource_arn == FIREWALL_ARN