Switched CVE Hunting to optional & Minor core feature (#482)

* Removed automatic registration of the k8s CVE hunter

* Made CVE hunting optional, default set to not run

kube_hunter/__main__.py

@@ -28,6 +28,7 @@
     k8s_auto_discover_nodes=args.k8s_auto_discover_nodes,
     service_account_token=args.service_account_token,
     kubeconfig=args.kubeconfig,
+    enable_cve_hunting=args.enable_cve_hunting,
 )
 setup_logger(args.log, args.log_file)
 set_config(config)

kube_hunter/conf/__init__.py

@@ -21,6 +21,7 @@ class Config:
     - remote: Hosts to scan
     - report: Output format
     - statistics: Include hunters statistics
+    - enable_cve_hunting: enables cve hunting, shows cve results
     """
 
     active: bool = False
@@ -39,6 +40,7 @@ class Config:
     k8s_auto_discover_nodes: bool = False
     service_account_token: Optional[str] = None
     kubeconfig: Optional[str] = None
+    enable_cve_hunting: bool = False
 
 
 _config: Optional[Config] = None

kube_hunter/conf/parser.py

@@ -76,6 +76,12 @@ def parser_add_arguments(parser):
 
     parser.add_argument("--active", action="store_true", help="Enables active hunting")
 
+    parser.add_argument(
+        "--enable-cve-hunting",
+        action="store_true",
+        help="Show cluster CVEs based on discovered version (Depending on different vendors, may result in False Positives)",
+    )
+
     parser.add_argument(
         "--log",
         type=str,

kube_hunter/core/events/handler.py

@@ -62,7 +62,7 @@ def __init__(self, num_worker=10):
     ######################################################
     """
 
-    def subscribe(self, event, hook=None, predicate=None):
+    def subscribe(self, event, hook=None, predicate=None, is_register=True):
         """
         The Subscribe Decorator - For Regular Registration
         Use this to register for one event only. Your hunter will execute each time this event is published
@@ -74,12 +74,12 @@ def subscribe(self, event, hook=None, predicate=None):
         """
 
         def wrapper(hook):
-            self.subscribe_event(event, hook=hook, predicate=predicate)
+            self.subscribe_event(event, hook=hook, predicate=predicate, is_register=is_register)
             return hook
 
         return wrapper
 
-    def subscribe_many(self, events, hook=None, predicates=None):
+    def subscribe_many(self, events, hook=None, predicates=None, is_register=True):
         """
         The Subscribe Many Decorator - For Multiple Registration,
         When your attack needs several prerequisites to exist in the cluster, You need to register for multiple events.
@@ -99,12 +99,12 @@ def subscribe_many(self, events, hook=None, predicates=None):
         """
 
         def wrapper(hook):
-            self.subscribe_events(events, hook=hook, predicates=predicates)
+            self.subscribe_events(events, hook=hook, predicates=predicates, is_register=is_register)
             return hook
 
         return wrapper
 
-    def subscribe_once(self, event, hook=None, predicate=None):
+    def subscribe_once(self, event, hook=None, predicate=None, is_register=True):
         """
         The Subscribe Once Decorator - For Single Trigger Registration,
         Use this when you want your hunter to execute only in your entire program run
@@ -125,7 +125,8 @@ def __new__unsubscribe_self(self, cls):
 
             hook.__new__ = __new__unsubscribe_self
 
-            self.subscribe_event(event, hook=hook, predicate=predicate)
+            self.subscribe_event(event, hook=hook, predicate=predicate, is_register=is_register)
+
             return hook
 
         return wrapper
@@ -256,7 +257,9 @@ def _register_hook(self, event, hook=None, predicate=None):
             self.hooks[event].append((hook, predicate))
             logging.debug("{} subscribed to {}".format(hook, event))
 
-    def subscribe_event(self, event, hook=None, predicate=None):
+    def subscribe_event(self, event, hook=None, predicate=None, is_register=True):
+        if not is_register:
+            return
         if not self._register_hunters(hook):
             return
 
@@ -267,7 +270,9 @@ def subscribe_event(self, event, hook=None, predicate=None):
         else:
             self._register_hook(event, hook, predicate)
 
-    def subscribe_events(self, events, hook=None, predicates=None):
+    def subscribe_events(self, events, hook=None, predicates=None, is_register=True):
+        if not is_register:
+            return False
         if not self._register_hunters(hook):
             return False
 

kube_hunter/modules/hunting/cves.py

@@ -3,7 +3,8 @@
 
 from kube_hunter.conf import get_config
 from kube_hunter.core.events import handler
-from kube_hunter.core.events.types import Vulnerability, Event, K8sVersionDisclosure
+
+from kube_hunter.core.events.types import K8sVersionDisclosure, Vulnerability, Event
 from kube_hunter.core.types import (
     Hunter,
     KubectlClient,
@@ -15,6 +16,7 @@
 from kube_hunter.modules.discovery.kubectl import KubectlClientEvent
 
 logger = logging.getLogger(__name__)
+config = get_config()
 
 
 class ServerApiVersionEndPointAccessPE(Vulnerability, Event):
@@ -199,7 +201,7 @@ def is_vulnerable(fix_versions, check_version, ignore_downstream=False):
         return vulnerable
 
 
-@handler.subscribe_once(K8sVersionDisclosure)
+@handler.subscribe_once(K8sVersionDisclosure, is_register=config.enable_cve_hunting)
 class K8sClusterCveHunter(Hunter):
     """K8s CVE Hunter
     Checks if Node is running a Kubernetes version vulnerable to
@@ -224,6 +226,7 @@ def execute(self):
                 self.publish_event(vulnerability(self.event.version))
 
 
+# Removed due to incomplete implementation for multiple vendors revisions of kubernetes
 @handler.subscribe(KubectlClientEvent)
 class KubectlCVEHunter(Hunter):
     """Kubectl CVE Hunter

tests/core/test_handler.py

@@ -1,6 +1,6 @@
 # flake8: noqa: E402
 
-from kube_hunter.conf import Config, set_config
+from kube_hunter.conf import Config, set_config, get_config
 
 set_config(Config(active=True))
 
@@ -23,7 +23,9 @@
 from kube_hunter.modules.hunting.arp import ArpSpoofHunter
 from kube_hunter.modules.hunting.capabilities import PodCapabilitiesHunter
 from kube_hunter.modules.hunting.certificates import CertificateDiscovery
-from kube_hunter.modules.hunting.cves import K8sClusterCveHunter, KubectlCVEHunter
+
+from kube_hunter.modules.hunting.cves import K8sClusterCveHunter
+from kube_hunter.modules.hunting.cves import KubectlCVEHunter
 from kube_hunter.modules.hunting.dashboard import KubeDashboard
 from kube_hunter.modules.hunting.dns import DnsSpoofHunter
 from kube_hunter.modules.hunting.etcd import EtcdRemoteAccess, EtcdRemoteAccessActive
@@ -40,6 +42,8 @@
 from kube_hunter.modules.hunting.proxy import KubeProxy, ProveProxyExposed, K8sVersionDisclosureProve
 from kube_hunter.modules.hunting.secrets import AccessSecrets
 
+config = get_config()
+
 PASSIVE_HUNTERS = {
     ApiServiceDiscovery,
     KubeDashboardDiscovery,
@@ -56,7 +60,6 @@
     ApiVersionHunter,
     PodCapabilitiesHunter,
     CertificateDiscovery,
-    K8sClusterCveHunter,
     KubectlCVEHunter,
     KubeDashboard,
     EtcdRemoteAccess,
@@ -67,6 +70,9 @@
     AccessSecrets,
 }
 
+# if config.enable_cve_hunting:
+#     PASSIVE_HUNTERS.append(K8sClusterCveHunter)
+
 ACTIVE_HUNTERS = {
     ProveAzureSpnExposure,
     AccessApiServerActive,