fix the bug of k8s node duplication due to the lack of judgment of th…

[y4ney]

Description

In order to avoid duplication of detected nodes, services and vulnerabilities, we need to determine the type of node address when the k8s cluster node is automatically found.

Fixed Issues

Fixes #527

"BEFORE" and "AFTER" output

BEFORE

./kube-hunter.py --k8s-auto-discover-nodes --kubeconfig /root/.kube/config
2022-11-11 02:48:11,574 INFO kube_hunter.modules.report.collector Started hunting
2022-11-11 02:48:11,574 INFO kube_hunter.modules.report.collector Discovering Open Kubernetes Services
2022-11-11 02:48:11,685 INFO kube_hunter.modules.discovery.kubernetes_client Listed 1 nodes in the cluster
2022-11-11 02:48:11,697 INFO kube_hunter.modules.report.collector Found open service "Etcd" at 192.168.1.133:2379
2022-11-11 02:48:11,721 INFO kube_hunter.modules.report.collector Found open service "Etcd" at k8s:2379
2022-11-11 02:48:11,815 INFO kube_hunter.modules.report.collector Found vulnerability "K8s Version Disclosure" in 192.168.1.133:6443
2022-11-11 02:48:11,820 INFO kube_hunter.modules.report.collector Found open service "API Server" at k8s:6443
2022-11-11 02:48:11,824 INFO kube_hunter.modules.report.collector Found vulnerability "K8s Version Disclosure" in k8s:6443
2022-11-11 02:48:11,831 INFO kube_hunter.modules.report.collector Found open service "API Server" at 192.168.1.133:6443
2022-11-11 02:48:11,928 INFO kube_hunter.modules.report.collector Found open service "Kubelet API" at 192.168.1.133:10250
2022-11-11 02:48:11,932 INFO kube_hunter.modules.report.collector Found open service "Kubelet API" at k8s:10250

Nodes
+-------------+---------------+
| TYPE        | LOCATION      |
+-------------+---------------+
| Node/Master | k8s           |
+-------------+---------------+
| Node/Master | 192.168.1.133 |
+-------------+---------------+

Detected Services
+-------------+---------------------+----------------------+
| SERVICE     | LOCATION            | DESCRIPTION          |
+-------------+---------------------+----------------------+
| Kubelet API | k8s:10250           | The Kubelet is the   |
|             |                     | main component in    |
|             |                     | every Node, all pod  |
|             |                     | operations goes      |
|             |                     | through the kubelet  |
+-------------+---------------------+----------------------+
| Kubelet API | 192.168.1.133:10250 | The Kubelet is the   |
|             |                     | main component in    |
|             |                     | every Node, all pod  |
|             |                     | operations goes      |
|             |                     | through the kubelet  |
+-------------+---------------------+----------------------+
| Etcd        | k8s:2379            | Etcd is a DB that    |
|             |                     | stores cluster's     |
|             |                     | data, it contains    |
|             |                     | configuration and    |
|             |                     | current              |
|             |                     |     state            |
|             |                     | information, and     |
|             |                     | might contain        |
|             |                     | secrets              |
+-------------+---------------------+----------------------+
| Etcd        | 192.168.1.133:2379  | Etcd is a DB that    |
|             |                     | stores cluster's     |
|             |                     | data, it contains    |
|             |                     | configuration and    |
|             |                     | current              |
|             |                     |     state            |
|             |                     | information, and     |
|             |                     | might contain        |
|             |                     | secrets              |
+-------------+---------------------+----------------------+
| API Server  | k8s:6443            | The API server is in |
|             |                     | charge of all        |
|             |                     | operations on the    |
|             |                     | cluster.             |
+-------------+---------------------+----------------------+
| API Server  | 192.168.1.133:6443  | The API server is in |
|             |                     | charge of all        |
|             |                     | operations on the    |
|             |                     | cluster.             |
+-------------+---------------------+----------------------+

Vulnerabilities
For further information about a vulnerability, search its ID in:
https://avd.aquasec.com/
+--------+--------------------+----------------------+----------------------+----------------------+----------+
| ID     | LOCATION           | MITRE CATEGORY       | VULNERABILITY        | DESCRIPTION          | EVIDENCE |
+--------+--------------------+----------------------+----------------------+----------------------+----------+
| KHV002 | k8s:6443           | Initial Access //    | K8s Version          | The kubernetes       | v1.23.7  |
|        |                    | Exposed sensitive    | Disclosure           | version could be     |          |
|        |                    | interfaces           |                      | obtained from the    |          |
|        |                    |                      |                      | /version endpoint    |          |
+--------+--------------------+----------------------+----------------------+----------------------+----------+
| KHV002 | 192.168.1.133:6443 | Initial Access //    | K8s Version          | The kubernetes       | v1.23.7  |
|        |                    | Exposed sensitive    | Disclosure           | version could be     |          |
|        |                    | interfaces           |                      | obtained from the    |          |
|        |                    |                      |                      | /version endpoint    |          |
+--------+--------------------+----------------------+----------------------+----------------------+----------+

AFTER

./kube-hunter.py --k8s-auto-discover-nodes --kubeconfig /root/.kube/config
2022-11-11 03:18:23,914 INFO kube_hunter.modules.report.collector Started hunting
2022-11-11 03:18:23,925 INFO kube_hunter.modules.report.collector Discovering Open Kubernetes Services
2022-11-11 03:18:23,971 INFO kube_hunter.modules.discovery.kubernetes_client Listed 1 nodes in the cluster
2022-11-11 03:18:23,975 INFO kube_hunter.modules.report.collector Found open service "Etcd" at 192.168.1.133:2379
2022-11-11 03:18:24,015 INFO kube_hunter.modules.report.collector Found open service "Kubelet API" at 192.168.1.133:10250
2022-11-11 03:18:24,056 INFO kube_hunter.modules.report.collector Found open service "API Server" at 192.168.1.133:6443
2022-11-11 03:18:24,056 INFO kube_hunter.modules.report.collector Found vulnerability "K8s Version Disclosure" in 192.168.1.133:6443

Nodes
+-------------+---------------+
| TYPE        | LOCATION      |
+-------------+---------------+
| Node/Master | 192.168.1.133 |
+-------------+---------------+

Detected Services
+-------------+---------------------+----------------------+
| SERVICE     | LOCATION            | DESCRIPTION          |
+-------------+---------------------+----------------------+
| Kubelet API | 192.168.1.133:10250 | The Kubelet is the   |
|             |                     | main component in    |
|             |                     | every Node, all pod  |
|             |                     | operations goes      |
|             |                     | through the kubelet  |
+-------------+---------------------+----------------------+
| Etcd        | 192.168.1.133:2379  | Etcd is a DB that    |
|             |                     | stores cluster's     |
|             |                     | data, it contains    |
|             |                     | configuration and    |
|             |                     | current              |
|             |                     |     state            |
|             |                     | information, and     |
|             |                     | might contain        |
|             |                     | secrets              |
+-------------+---------------------+----------------------+
| API Server  | 192.168.1.133:6443  | The API server is in |
|             |                     | charge of all        |
|             |                     | operations on the    |
|             |                     | cluster.             |
+-------------+---------------------+----------------------+

Vulnerabilities
For further information about a vulnerability, search its ID in:
https://avd.aquasec.com/
+--------+--------------------+----------------------+----------------------+----------------------+----------+
| ID     | LOCATION           | MITRE CATEGORY       | VULNERABILITY        | DESCRIPTION          | EVIDENCE |
+--------+--------------------+----------------------+----------------------+----------------------+----------+
| KHV002 | 192.168.1.133:6443 | Initial Access //    | K8s Version          | The kubernetes       | v1.23.7  |
|        |                    | Exposed sensitive    | Disclosure           | version could be     |          |
|        |                    | interfaces           |                      | obtained from the    |          |
|        |                    |                      |                      | /version endpoint    |          |
+--------+--------------------+----------------------+----------------------+----------------------+----------+

Contribution checklist

• I have read the Contributing Guidelines.
• The commits refer to an active issue in the repository.
• I have added automated testing to cover this case.

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