Add remediation job for closing port 22 for VM (#11)

* PLA-18743: Add remediation job for closing port 22 for VM
* add tests for azure_vm_close_port_22 to tox
* add deployment details

Co-authored-by: Mohammad Zuber Khan <[email protected]>

remediation_worker/jobs/azure_vm_close_port_22/README.md

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+# Close Port 22 for a VM
+
+This job blocks public access to port 22 for the VM.
+
+### Applicable Rule
+
+##### Rule ID:
+d7a3ad03-860c-4928-9ba8-789e84a835be
+
+##### Rule Name:
+A virtual machine is publicly accessible to the internet via port 22
+
+## Getting Started
+
+### Prerequisites
+
+The provided Azure service principal must have permissions to make changes to the network security groups and security
+rules.
+Details for the permissions can be found [here](https://docs.microsoft.com/en-us/azure/virtual-network/manage-network-security-group#permissions):
+
+
+### Running the script
+
+You may run this script using following commands:
+```shell script
+  pip install -r requirements.txt
+  python3 azure_vm_close_port_22.py
+```
+
+## Running the tests
+You may run test using following command under vss-remediation-worker-job-code-python directory:
+```shell script
+    python3 -m pytest test
+```
+
+## Deployment
+1. Provision a Virtual Machine
+Create an EC2 instance to use for the worker. The minimum required specifications are 128 MB memory and 1/2 Core CPU.
+2. Setup Docker
+Install Docker on the newly provisioned EC2 instance. You can refer to the [docs here](https://docs.aws.amazon.com/AmazonECS/latest/developerguide/docker-basics.html) for more information.
+3. Deploy the worker image
+SSH into the EC2 instance and run the command below to deploy the worker image:
+```shell script
+  docker run --rm -it --name worker \
+  -e VSS_CLIENT_ID={ENTER CLIENT ID}
+  -e VSS_CLIENT_SECRET={ENTER CLIENT SECRET} \
+  vmware/vss-remediation-worker:latest-python
+```
+
+
+## Contributing
+The Secure State team welcomes contributions from the community. If you wish to contribute code and you have not signed our contributor license agreement (CLA), our bot will update the issue when you open a Pull Request. For any questions about the CLA process, please refer to our [FAQ](https://cla.vmware.com/faq).
+All contributions to this repository must be signed as described on that page. Your signature certifies that you wrote the patch or have the right to pass it on as an open-source patch.
+
+For more detailed information, refer to [CONTRIBUTING.md](../../../CONTRIBUTING.md).
+
+## Versioning
+
+We use [SemVer](http://semver.org/) for versioning. For the versions available, see the [tags on this repository](https://github.com/your/project/tags).
+
+## Authors
+
+* **VMware Secure State** - *Initial work*
+
+See also the list of [contributors](https://github.com/your/project/contributors) who participated in this project.
+
+## License
+
+This project is licensed under the Apache License - see the [LICENSE](https://github.com/vmware-samples/secure-state-remediation-jobs/blob/master/LICENSE.txt) file for details

remediation_worker/jobs/azure_vm_close_port_22/azure_vm_close_port_22.py

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+# Copyright (c) 2020 VMware Inc.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import json
+import os
+import sys
+import logging
+
+from azure.mgmt.compute import ComputeManagementClient
+from azure.mgmt.network import NetworkManagementClient
+from azure.common.credentials import ServicePrincipalCredentials
+
+logging.basicConfig(level=logging.INFO)
+
+
+def logcall(f, *args, **kwargs):
+    logging.info(
+        "%s(%s)",
+        f.__name__,
+        ", ".join(list(args) + [f"{k}={repr(v)}" for k, v in kwargs.items()]),
+    )
+    logging.info(f(*args, **kwargs))
+
+
+class VMSecurityGroupClosePort22(object):
+    def parse(self, payload):
+        """Parse payload received from Remediation Service.
+
+        :param payload: JSON string containing parameters received from the remediation service.
+        :type payload: str.
+        :returns: Dictionary of parsed parameters
+        :rtype: dict
+        :raises: KeyError, JSONDecodeError
+        """
+        remediation_entry = json.loads(payload)
+
+        vm_name = remediation_entry["notificationInfo"]["FindingInfo"]["ObjectId"]
+        region = remediation_entry["notificationInfo"]["FindingInfo"]["Region"]
+
+        object_chain = remediation_entry["notificationInfo"]["FindingInfo"][
+            "ObjectChain"
+        ]
+        object_chain_dict = json.loads(object_chain)
+        subscription_id = object_chain_dict["cloudAccountId"]
+
+        properties = object_chain_dict["properties"]
+        resource_group_name = ""
+        for property in properties:
+            if property["name"] == "ResourceGroup" and property["type"] == "string":
+                resource_group_name = property["stringV"]
+                break
+
+        logging.info("parsed params")
+        logging.info(f"  resource_group_name: {resource_group_name}")
+        logging.info(f"  vm_name: {vm_name}")
+        logging.info(f"  subscription_id: {subscription_id}")
+        logging.info(f"  region: {region}")
+
+        return {
+            "vm_name": vm_name,
+            "resource_group_name": resource_group_name,
+            "subscription_id": subscription_id,
+            "region": region,
+        }
+
+    def remediate(self, compute_client, network_client, resource_group_name, vm_name):
+        """Block public access to port 22 of the VM
+
+        :param compute_client: Instance of the Azure ComputeManagementClient.
+        :param network_client: Instance of the Azure NetworkManagementClient.
+        :param resource_group_name: The name of the resource group to which the security_group belongs
+        :param vm_name: The name of the VM. You must specify the VM name in the request.
+        :type vm_name: str.
+        :type resource_group_name: str.
+        :returns: Integer signaling success or failure
+        :rtype: int
+        :raises: msrestazure.azure_exceptions.CloudError
+        """
+
+        port = 22
+        vm = compute_client.virtual_machines.get(resource_group_name, vm_name)
+        nw_interfaces = vm.network_profile.network_interfaces
+
+        for nw_interface in nw_interfaces:
+            nw_interface_name = self._get_name_from_id(nw_interface.id)
+            nw_interface_details = network_client.network_interfaces.get(
+                resource_group_name, nw_interface_name
+            )
+            security_group_name = self._get_name_from_id(
+                nw_interface_details.network_security_group.id
+            )
+            network_security_group = network_client.network_security_groups.get(
+                resource_group_name=resource_group_name,
+                network_security_group_name=security_group_name,
+            )
+
+            security_rules = network_security_group.security_rules
+
+            for rule in security_rules:
+                if (
+                    rule.access != "Allow"
+                    or rule.direction != "Inbound"
+                    or rule.source_address_prefix != "*"
+                ):
+                    continue
+                if rule.destination_port_range is not None:
+                    if int(rule.destination_port_range) == port:
+                        security_rules.remove(rule)
+                else:
+                    port_ranges = rule.destination_port_ranges
+                    new_ranges = self._find_and_remove_port(port_ranges, port)
+                    rule.destination_port_ranges = new_ranges
+
+            network_security_group.security_rules = security_rules
+
+            # Revoke permission for port 22
+            logging.info("revoking permissions for port 22")
+            try:
+                logging.info(
+                    "    executing client.network_security_groups.create_or_update"
+                )
+                logging.info(f"      resource_group_name={resource_group_name}")
+                logging.info(f"      network_security_group_name={security_group_name}")
+                network_client.network_security_groups.create_or_update(
+                    resource_group_name, security_group_name, network_security_group
+                )
+            except Exception as e:
+                logging.error(f"{str(e)}")
+                raise
+
+        return 0
+
+    def _get_name_from_id(self, id):
+        return id.split("/")[-1]
+
+    def _find_and_remove_port(self, port_ranges, port):
+        """Remove the port from the port range.
+
+        :param port_ranges: port ranges to be updated.
+        :param port: port to be removed
+        :type port_ranges: list.
+        :type port: int
+        :returns: list of port_ranges
+        """
+        result = []
+        for port_range in port_ranges:
+            if "-" in port_range:
+                boundaries = port_range.split("-")
+                if int(boundaries[0]) <= port and int(boundaries[1]) >= port:
+                    if int(boundaries[0]) == port:
+                        new_range_start = port + 1
+                        new_range_end = int(boundaries[1])
+                        if new_range_start != new_range_end:
+                            result.append(
+                                str(new_range_start) + "-" + str(new_range_end)
+                            )
+                        else:
+                            result.append(str(new_range_start))
+                    elif int(boundaries[1]) == port:
+                        new_range_start = int(boundaries[0])
+                        new_range_end = port - 1
+                        if new_range_start != new_range_end:
+                            result.append(
+                                str(new_range_start) + "-" + str(new_range_end)
+                            )
+                        else:
+                            result.append(str(new_range_start))
+                    else:
+                        range1_start = int(boundaries[0])
+                        range1_end = port - 1
+                        range2_start = port + 1
+                        range2_end = int(boundaries[1])
+
+                        if range1_start != range1_end:
+                            result.append(str(range1_start) + "-" + str(range1_end))
+                        else:
+                            result.append(str(range1_start))
+
+                        if range2_start != range2_end:
+                            result.append(str(range2_start) + "-" + str(range2_end))
+                        else:
+                            result.append(str(range2_start))
+                else:
+                    result.append(port_range)
+            elif int(port_range) != port:
+                result.append(port_range)
+        return result
+
+    def run(self, args):
+        """Run the remediation job.
+
+        :param args: List of arguments provided to the job.
+        :type args: list.
+        :returns: int
+        """
+        params = self.parse(args[1])
+
+        credentials = ServicePrincipalCredentials(
+            client_id=os.environ.get("AZURE_CLIENT_ID"),
+            secret=os.environ.get("AZURE_CLIENT_SECRET"),
+            tenant=os.environ.get("AZURE_TENANT_ID"),
+        )
+
+        compute_client = ComputeManagementClient(credentials, params["subscription_id"])
+        nw_client = NetworkManagementClient(credentials, params["subscription_id"])
+        return self.remediate(
+            compute_client,
+            nw_client,
+            params["resource_group_name"],
+            params["security_group_name"],
+        )
+
+
+if __name__ == "__main__":
+    sys.exit(VMSecurityGroupClosePort22().run(sys.argv))