feat(awslambda): add new check awslambda_function_vpc_multi_az (#4816)

Co-authored-by: Sergio <sergio@prowler.com>

tests/providers/aws/services/awslambda/awslambda_function_vpc_multi_az/awslambda_function_vpc_multi_az_test.py

@@ -0,0 +1,548 @@
+from json import dumps
+from unittest import mock
+
+from boto3 import client
+from moto import mock_aws
+
+from tests.providers.aws.utils import (
+    AWS_REGION_EU_WEST_1,
+    AWS_REGION_EU_WEST_1_AZA,
+    AWS_REGION_EU_WEST_1_AZB,
+    set_mocked_aws_provider,
+)
+
+
+class Test_awslambda_function_vpc_is_in_multi_azs:
+    @mock_aws
+    def test_no_functions(self):
+        from prowler.providers.aws.services.awslambda.awslambda_service import Lambda
+
+        aws_provider = set_mocked_aws_provider([AWS_REGION_EU_WEST_1])
+
+        with mock.patch(
+            "prowler.providers.common.provider.Provider.get_global_provider",
+            return_value=aws_provider,
+        ), mock.patch(
+            "prowler.providers.aws.services.awslambda.awslambda_function_vpc_multi_az.awslambda_function_vpc_multi_az.awslambda_client",
+            new=Lambda(aws_provider),
+        ):
+            # Test Check
+            from prowler.providers.aws.services.awslambda.awslambda_function_vpc_multi_az.awslambda_function_vpc_multi_az import (
+                awslambda_function_vpc_multi_az,
+            )
+
+            check = awslambda_function_vpc_multi_az()
+            result = check.execute()
+
+            assert len(result) == 0
+
+    @mock_aws
+    def test_function_outside_vpc(self):
+        # Create IAM Role for Lambda Function
+        iam_client = client("iam", region_name=AWS_REGION_EU_WEST_1)
+        role_name = "test-role"
+        assume_role_policy_document = {
+            "Version": "2012-10-17",
+            "Statement": [
+                {
+                    "Effect": "Allow",
+                    "Principal": {"Service": "lambda.amazonaws.com"},
+                    "Action": "sts:AssumeRole",
+                }
+            ],
+        }
+        role_arn = iam_client.create_role(
+            RoleName=role_name,
+            AssumeRolePolicyDocument=dumps(assume_role_policy_document),
+        )["Role"]["Arn"]
+
+        # Create Lambda Function outside VPC
+        lambda_client = client("lambda", region_name=AWS_REGION_EU_WEST_1)
+        function_name = "test_function_outside_vpc"
+        function_arn = lambda_client.create_function(
+            FunctionName=function_name,
+            Runtime="python3.8",
+            Role=role_arn,
+            Handler="lambda_function.lambda_handler",
+            Code={"ZipFile": b"file not used"},
+        )["FunctionArn"]
+
+        from prowler.providers.aws.services.awslambda.awslambda_service import Lambda
+
+        aws_provider = set_mocked_aws_provider([AWS_REGION_EU_WEST_1])
+
+        with mock.patch(
+            "prowler.providers.common.provider.Provider.get_global_provider",
+            return_value=aws_provider,
+        ), mock.patch(
+            "prowler.providers.aws.services.awslambda.awslambda_function_vpc_multi_az.awslambda_function_vpc_multi_az.awslambda_client",
+            new=Lambda(aws_provider),
+        ):
+            # Test Check
+            from prowler.providers.aws.services.awslambda.awslambda_function_vpc_multi_az.awslambda_function_vpc_multi_az import (
+                awslambda_function_vpc_multi_az,
+            )
+
+            check = awslambda_function_vpc_multi_az()
+            result = check.execute()
+
+            assert len(result) == 1
+            assert result[0].status == "FAIL"
+            assert (
+                result[0].status_extended
+                == f"Lambda function {function_name} is not inside a VPC."
+            )
+            assert result[0].region == AWS_REGION_EU_WEST_1
+            assert result[0].resource_id == function_name
+            assert result[0].resource_arn == function_arn
+            assert result[0].resource_tags == [{}]
+
+    @mock_aws
+    def test_function_in_vpc_single_az(self):
+        # Create IAM Role for Lambda Function
+        iam_client = client("iam", region_name=AWS_REGION_EU_WEST_1)
+        role_name = "test-role"
+        assume_role_policy_document = {
+            "Version": "2012-10-17",
+            "Statement": [
+                {
+                    "Effect": "Allow",
+                    "Principal": {"Service": "lambda.amazonaws.com"},
+                    "Action": "sts:AssumeRole",
+                }
+            ],
+        }
+        role_arn = iam_client.create_role(
+            RoleName=role_name,
+            AssumeRolePolicyDocument=dumps(assume_role_policy_document),
+        )["Role"]["Arn"]
+
+        # Create VPC
+        ec2_client = client("ec2", region_name=AWS_REGION_EU_WEST_1)
+        vpc_id = ec2_client.create_vpc(CidrBlock="10.0.0.0/16")["Vpc"]["VpcId"]
+
+        # Create Subnet
+        subnet_id = ec2_client.create_subnet(
+            VpcId=vpc_id,
+            CidrBlock="10.0.1.0/24",
+            AvailabilityZone=AWS_REGION_EU_WEST_1_AZA,
+        )["Subnet"]["SubnetId"]
+
+        # Create Security Group
+        security_group_id = ec2_client.create_security_group(
+            GroupName="test-sg", Description="Test SG", VpcId=vpc_id
+        )["GroupId"]
+
+        # Create Lambda Function inside VPC
+        lambda_client = client("lambda", region_name=AWS_REGION_EU_WEST_1)
+
+        function_name = "test_function_in_vpc_single_az"
+
+        function = lambda_client.create_function(
+            FunctionName=function_name,
+            Runtime="python3.8",
+            Role=role_arn,
+            Handler="lambda_function.lambda_handler",
+            Code={"ZipFile": b"file not used"},
+            VpcConfig={
+                "SubnetIds": [subnet_id],
+                "SecurityGroupIds": [security_group_id],
+            },
+        )
+        function_vpc_id = function["VpcConfig"]["VpcId"]
+
+        from prowler.providers.aws.services.awslambda.awslambda_service import Lambda
+        from prowler.providers.aws.services.vpc.vpc_service import VPC
+
+        aws_provider = set_mocked_aws_provider([AWS_REGION_EU_WEST_1])
+
+        with mock.patch(
+            "prowler.providers.common.provider.Provider.get_global_provider",
+            return_value=aws_provider,
+        ), mock.patch(
+            "prowler.providers.aws.services.awslambda.awslambda_function_vpc_multi_az.awslambda_function_vpc_multi_az.awslambda_client",
+            new=Lambda(aws_provider),
+        ), mock.patch(
+            "prowler.providers.aws.services.awslambda.awslambda_function_vpc_multi_az.awslambda_function_vpc_multi_az.vpc_client",
+            new=VPC(aws_provider),
+        ):
+            # Test Check
+            from prowler.providers.aws.services.awslambda.awslambda_function_vpc_multi_az.awslambda_function_vpc_multi_az import (
+                awslambda_function_vpc_multi_az,
+            )
+
+            check = awslambda_function_vpc_multi_az()
+            result = check.execute()
+
+            assert len(result) == 1
+            assert result[0].status == "FAIL"
+            assert (
+                result[0].status_extended
+                == f"Lambda function {function_name} is inside of VPC {function_vpc_id} that spans only in 1 AZs: {AWS_REGION_EU_WEST_1_AZA}. Must span in at least 2 AZs."
+            )
+            assert result[0].region == AWS_REGION_EU_WEST_1
+            assert result[0].resource_id == function_name
+            assert result[0].resource_arn == function["FunctionArn"]
+            assert result[0].resource_tags == [{}]
+
+    @mock_aws
+    def test_function_in_vpc_multiple_az(self):
+        # Create IAM Role for Lambda Function
+        iam_client = client("iam", region_name=AWS_REGION_EU_WEST_1)
+        role_name = "test-role"
+        assume_role_policy_document = {
+            "Version": "2012-10-17",
+            "Statement": [
+                {
+                    "Effect": "Allow",
+                    "Principal": {"Service": "lambda.amazonaws.com"},
+                    "Action": "sts:AssumeRole",
+                }
+            ],
+        }
+        role_arn = iam_client.create_role(
+            RoleName=role_name,
+            AssumeRolePolicyDocument=dumps(assume_role_policy_document),
+        )["Role"]["Arn"]
+
+        # Create VPC
+        ec2_client = client("ec2", region_name=AWS_REGION_EU_WEST_1)
+        vpc_id = ec2_client.create_vpc(CidrBlock="10.0.0.0/16")["Vpc"]["VpcId"]
+
+        # Create Subnets
+        subnet_id_a = ec2_client.create_subnet(
+            VpcId=vpc_id,
+            CidrBlock="10.0.1.0/24",
+            AvailabilityZone=AWS_REGION_EU_WEST_1_AZA,
+        )["Subnet"]["SubnetId"]
+
+        subnet_id_b = ec2_client.create_subnet(
+            VpcId=vpc_id,
+            CidrBlock="10.0.2.0/24",
+            AvailabilityZone=AWS_REGION_EU_WEST_1_AZB,
+        )["Subnet"]["SubnetId"]
+
+        # Create Security Group
+        security_group_id = ec2_client.create_security_group(
+            GroupName="test-sg", Description="Test SG", VpcId=vpc_id
+        )["GroupId"]
+
+        # Create Lambda Function inside VPC
+        lambda_client = client("lambda", region_name=AWS_REGION_EU_WEST_1)
+
+        function_name = "test_function_in_vpc_multiple_az"
+
+        function = lambda_client.create_function(
+            FunctionName=function_name,
+            Runtime="python3.8",
+            Role=role_arn,
+            Handler="lambda_function.lambda_handler",
+            Code={"ZipFile": b"file not used"},
+            VpcConfig={
+                "SubnetIds": [subnet_id_a, subnet_id_b],
+                "SecurityGroupIds": [security_group_id],
+            },
+        )
+
+        from prowler.providers.aws.services.awslambda.awslambda_service import Lambda
+        from prowler.providers.aws.services.vpc.vpc_service import VPC
+
+        aws_provider = set_mocked_aws_provider([AWS_REGION_EU_WEST_1])
+
+        with mock.patch(
+            "prowler.providers.common.provider.Provider.get_global_provider",
+            return_value=aws_provider,
+        ), mock.patch(
+            "prowler.providers.aws.services.awslambda.awslambda_function_vpc_multi_az.awslambda_function_vpc_multi_az.awslambda_client",
+            new=Lambda(aws_provider),
+        ), mock.patch(
+            "prowler.providers.aws.services.awslambda.awslambda_function_vpc_multi_az.awslambda_function_vpc_multi_az.vpc_client",
+            new=VPC(aws_provider),
+        ):
+            # Test Check
+            from prowler.providers.aws.services.awslambda.awslambda_function_vpc_multi_az.awslambda_function_vpc_multi_az import (
+                awslambda_function_vpc_multi_az,
+            )
+
+            check = awslambda_function_vpc_multi_az()
+            result = check.execute()
+
+            assert len(result) == 1
+            assert result[0].status == "PASS"
+            assert (
+                result[0].status_extended
+                == f"Lambda function {function_name} is inside of VPC {function['VpcConfig']['VpcId']} that spans in at least 2 AZs: {AWS_REGION_EU_WEST_1_AZB}, {AWS_REGION_EU_WEST_1_AZA}."
+            ) or (
+                result[0].status_extended
+                == f"Lambda function {function_name} is inside of VPC {function['VpcConfig']['VpcId']} that spans in at least 2 AZs: {AWS_REGION_EU_WEST_1_AZA}, {AWS_REGION_EU_WEST_1_AZB}."
+            )
+            assert result[0].region == AWS_REGION_EU_WEST_1
+            assert result[0].resource_id == function_name
+            assert result[0].resource_arn == function["FunctionArn"]
+            assert result[0].resource_tags == [{}]
+
+    @mock_aws
+    def test_function_with_multiple_subnets_in_same_az(self):
+        # Create IAM Role for Lambda Function
+        iam_client = client("iam", region_name=AWS_REGION_EU_WEST_1)
+        role_name = "test-role"
+        assume_role_policy_document = {
+            "Version": "2012-10-17",
+            "Statement": [
+                {
+                    "Effect": "Allow",
+                    "Principal": {"Service": "lambda.amazonaws.com"},
+                    "Action": "sts:AssumeRole",
+                }
+            ],
+        }
+        role_arn = iam_client.create_role(
+            RoleName=role_name,
+            AssumeRolePolicyDocument=dumps(assume_role_policy_document),
+        )["Role"]["Arn"]
+
+        # Create VPC
+        ec2_client = client("ec2", region_name=AWS_REGION_EU_WEST_1)
+        vpc_id = ec2_client.create_vpc(CidrBlock="10.0.0.0/16")["Vpc"]["VpcId"]
+
+        # Create Subnets
+        subnet_id_a = ec2_client.create_subnet(
+            VpcId=vpc_id,
+            CidrBlock="10.0.1.0/24",
+            AvailabilityZone=AWS_REGION_EU_WEST_1_AZA,
+        )["Subnet"]["SubnetId"]
+
+        subnet_id_b = ec2_client.create_subnet(
+            VpcId=vpc_id,
+            CidrBlock="10.0.2.0/24",
+            AvailabilityZone=AWS_REGION_EU_WEST_1_AZA,
+        )["Subnet"]["SubnetId"]
+
+        # Create Security Group
+        security_group_id = ec2_client.create_security_group(
+            GroupName="test-sg", Description="Test SG", VpcId=vpc_id
+        )["GroupId"]
+
+        # Create Lambda Function inside VPC
+        lambda_client = client("lambda", region_name=AWS_REGION_EU_WEST_1)
+
+        function_name = "test_function_in_vpc_multiple_subnets_same_az"
+
+        function = lambda_client.create_function(
+            FunctionName=function_name,
+            Runtime="python3.8",
+            Role=role_arn,
+            Handler="lambda_function.lambda_handler",
+            Code={"ZipFile": b"file not used"},
+            VpcConfig={
+                "SubnetIds": [subnet_id_a, subnet_id_b],
+                "SecurityGroupIds": [security_group_id],
+            },
+        )
+
+        from prowler.providers.aws.services.awslambda.awslambda_service import Lambda
+        from prowler.providers.aws.services.vpc.vpc_service import VPC
+
+        aws_provider = set_mocked_aws_provider([AWS_REGION_EU_WEST_1])
+
+        with mock.patch(
+            "prowler.providers.common.provider.Provider.get_global_provider",
+            return_value=aws_provider,
+        ), mock.patch(
+            "prowler.providers.aws.services.awslambda.awslambda_function_vpc_multi_az.awslambda_function_vpc_multi_az.awslambda_client",
+            new=Lambda(aws_provider),
+        ), mock.patch(
+            "prowler.providers.aws.services.awslambda.awslambda_function_vpc_multi_az.awslambda_function_vpc_multi_az.vpc_client",
+            new=VPC(aws_provider),
+        ):
+            # Test Check
+            from prowler.providers.aws.services.awslambda.awslambda_function_vpc_multi_az.awslambda_function_vpc_multi_az import (
+                awslambda_function_vpc_multi_az,
+            )
+
+            check = awslambda_function_vpc_multi_az()
+            result = check.execute()
+
+            assert len(result) == 1
+            assert result[0].status == "FAIL"
+            assert (
+                result[0].status_extended
+                == f"Lambda function {function_name} is inside of VPC {function['VpcConfig']['VpcId']} that spans only in 1 AZs: {AWS_REGION_EU_WEST_1_AZA}. Must span in at least 2 AZs."
+            )
+            assert result[0].region == AWS_REGION_EU_WEST_1
+            assert result[0].resource_id == function_name
+            assert result[0].resource_arn == function["FunctionArn"]
+            assert result[0].resource_tags == [{}]
+
+    @mock_aws
+    def test_function_no_vpc_pass_to_avoid_fail_twice(self):
+        # Create IAM Role for Lambda Function
+        iam_client = client("iam", region_name=AWS_REGION_EU_WEST_1)
+        role_name = "test-role"
+        assume_role_policy_document = {
+            "Version": "2012-10-17",
+            "Statement": [
+                {
+                    "Effect": "Allow",
+                    "Principal": {"Service": "lambda.amazonaws.com"},
+                    "Action": "sts:AssumeRole",
+                }
+            ],
+        }
+        role_arn = iam_client.create_role(
+            RoleName=role_name,
+            AssumeRolePolicyDocument=dumps(assume_role_policy_document),
+        )["Role"]["Arn"]
+
+        # Create Lambda Function outside VPC
+        lambda_client = client("lambda", region_name=AWS_REGION_EU_WEST_1)
+        function_name = "test_function_no_vpc_pass_to_avoid_fail_twice"
+        lambda_client.create_function(
+            FunctionName=function_name,
+            Runtime="python3.8",
+            Role=role_arn,
+            Handler="lambda_function.lambda_handler",
+            Code={"ZipFile": b"file not used"},
+        )["FunctionArn"]
+
+        from prowler.providers.aws.services.awslambda.awslambda_service import Lambda
+        from prowler.providers.aws.services.vpc.vpc_service import VPC
+
+        aws_provider = set_mocked_aws_provider([AWS_REGION_EU_WEST_1])
+
+        with mock.patch(
+            "prowler.providers.common.provider.Provider.get_global_provider",
+            return_value=aws_provider,
+        ), mock.patch(
+            "prowler.providers.aws.services.awslambda.awslambda_function_vpc_multi_az.awslambda_function_vpc_multi_az.awslambda_client",
+            new=Lambda(aws_provider),
+        ), mock.patch(
+            "prowler.providers.aws.services.awslambda.awslambda_function_vpc_multi_az.awslambda_function_vpc_multi_az.vpc_client",
+            new=VPC(aws_provider),
+        ), mock.patch(
+            "prowler.providers.aws.services.awslambda.awslambda_function_inside_vpc.awslambda_function_inside_vpc.awslambda_client",
+            new=Lambda(aws_provider),
+        ):
+            # Test check inside_vpc first
+
+            from prowler.providers.aws.services.awslambda.awslambda_function_inside_vpc.awslambda_function_inside_vpc import (
+                awslambda_function_inside_vpc,
+            )
+
+            check = awslambda_function_inside_vpc()
+
+            result = check.execute()
+
+            assert len(result) == 1
+            assert result[0].status == "FAIL"
+
+            # Now test if function is in multiple AZs to ensure it does not fail twice
+
+            from prowler.providers.aws.services.awslambda.awslambda_function_vpc_multi_az.awslambda_function_vpc_multi_az import (
+                awslambda_function_vpc_multi_az,
+            )
+
+            check = awslambda_function_vpc_multi_az()
+            result = check.execute()
+
+            assert len(result) == 0
+
+    @mock_aws
+    def test_resource_filtered(self):
+        # Create a compliant Lambda Function
+
+        # Create IAM Role for Lambda Function
+        iam_client = client("iam", region_name=AWS_REGION_EU_WEST_1)
+        role_name = "test-role"
+        assume_role_policy_document = {
+            "Version": "2012-10-17",
+            "Statement": [
+                {
+                    "Effect": "Allow",
+                    "Principal": {"Service": "lambda.amazonaws.com"},
+                    "Action": "sts:AssumeRole",
+                }
+            ],
+        }
+        role_arn = iam_client.create_role(
+            RoleName=role_name,
+            AssumeRolePolicyDocument=dumps(assume_role_policy_document),
+        )["Role"]["Arn"]
+
+        # Create VPC
+        ec2_client = client("ec2", region_name=AWS_REGION_EU_WEST_1)
+        vpc_id = ec2_client.create_vpc(CidrBlock="10.0.0.0/16")["Vpc"]["VpcId"]
+
+        # Create Subnets
+        subnet_id_a = ec2_client.create_subnet(
+            VpcId=vpc_id,
+            CidrBlock="10.0.1.0/24",
+            AvailabilityZone=AWS_REGION_EU_WEST_1_AZA,
+        )["Subnet"]["SubnetId"]
+
+        subnet_id_b = ec2_client.create_subnet(
+            VpcId=vpc_id,
+            CidrBlock="10.0.2.0/24",
+            AvailabilityZone=AWS_REGION_EU_WEST_1_AZB,
+        )["Subnet"]["SubnetId"]
+
+        # Create Security Group
+        security_group_id = ec2_client.create_security_group(
+            GroupName="test-sg", Description="Test SG", VpcId=vpc_id
+        )["GroupId"]
+
+        # Create Lambda Function inside VPC
+        lambda_client = client("lambda", region_name=AWS_REGION_EU_WEST_1)
+
+        function_name = "test_function_resource_filtered"
+
+        function = lambda_client.create_function(
+            FunctionName=function_name,
+            Runtime="python3.8",
+            Role=role_arn,
+            Handler="lambda_function.lambda_handler",
+            Code={"ZipFile": b"file not used"},
+            VpcConfig={
+                "SubnetIds": [subnet_id_a, subnet_id_b],
+                "SecurityGroupIds": [security_group_id],
+            },
+        )
+
+        from prowler.providers.aws.services.awslambda.awslambda_service import Lambda
+        from prowler.providers.aws.services.vpc.vpc_service import VPC
+
+        aws_provider = set_mocked_aws_provider([AWS_REGION_EU_WEST_1])
+
+        # Filter the resource in the provider, this is like the --resource-arn option
+        aws_provider._audit_resources = [function["FunctionArn"]]
+
+        with mock.patch(
+            "prowler.providers.common.provider.Provider.get_global_provider",
+            return_value=aws_provider,
+        ), mock.patch(
+            "prowler.providers.aws.services.awslambda.awslambda_function_vpc_multi_az.awslambda_function_vpc_multi_az.awslambda_client",
+            new=Lambda(aws_provider),
+        ), mock.patch(
+            "prowler.providers.aws.services.awslambda.awslambda_function_vpc_multi_az.awslambda_function_vpc_multi_az.vpc_client",
+            new=VPC(aws_provider),
+        ):
+            # Test Check
+            from prowler.providers.aws.services.awslambda.awslambda_function_vpc_multi_az.awslambda_function_vpc_multi_az import (
+                awslambda_function_vpc_multi_az,
+            )
+
+            check = awslambda_function_vpc_multi_az()
+            result = check.execute()
+
+            assert len(result) == 1
+            assert (
+                result[0].status == "FAIL"
+            )  # This should be a PASS, but the resource is filtered so subnets are filtered and this is a bug
+            assert (
+                result[0].status_extended
+                == f"Lambda function {function_name} is inside of VPC {function['VpcConfig']['VpcId']} that spans only in 0 AZs: . Must span in at least 2 AZs."
+            )
+            assert result[0].region == AWS_REGION_EU_WEST_1
+            assert result[0].resource_id == function_name
+            assert result[0].resource_arn == function["FunctionArn"]
+            assert result[0].resource_tags == [{}]

tests/providers/aws/services/awslambda/awslambda_service_test.py

@@ -221,6 +221,7 @@ class Test_Lambda_Service:
                 lambda_arn_1
             ].url_config.cors_config.allow_origins == ["*"]
             assert awslambda.functions[lambda_arn_1].vpc_id == "vpc-123abc"
+            assert awslambda.functions[lambda_arn_1].subnet_ids == {"subnet-123abc"}
 
             assert awslambda.functions[lambda_arn_1].tags == [{"test": "test"}]