fix(kubernetes): reject exec auth in cloud kubeconfigs (#11753)

api/CHANGELOG.md

@@ -24,6 +24,7 @@ All notable changes to the **Prowler API** are documented in this file.
 ### 🔐 Security
 
 - User profile updates now allow users to update their own account while requiring user-management permissions to update other users in the same tenant [(#11792)](https://github.com/prowler-cloud/prowler/pull/11792)
+- Kubernetes provider credentials now reject kubeconfigs using `exec` authentication in Prowler Cloud, preventing user-supplied commands from running on Cloud workers [(#11753)](https://github.com/prowler-cloud/prowler/pull/11753)
 
 ---
 
@@ -44,6 +45,8 @@ All notable changes to the **Prowler API** are documented in this file.
 - Attack Paths: Provider graph cleanup now deletes Neo4j and Neptune relationships in directed batches before deleting nodes [(#11755)](https://github.com/prowler-cloud/prowler/pull/11755)
 - `scan-perform` no longer reports an error when a provider is deleted during a running scan [(#11696)](https://github.com/prowler-cloud/prowler/pull/11696)
 
+---
+
 ## [1.32.1] (Prowler v5.31.1)
 
 ### 🐞 Fixed

api/src/backend/api/tests/test_serializers.py

@@ -1,6 +1,6 @@
 import pytest
 from api.v1.serializer_utils.integrations import S3ConfigSerializer
-from api.v1.serializers import ImageProviderSecret
+from api.v1.serializers import ImageProviderSecret, KubernetesProviderSecret
 from rest_framework.exceptions import ValidationError
 
 
@@ -132,3 +132,74 @@ class TestImageProviderSecret:
         serializer = ImageProviderSecret(data={"registry_password": "pass"})
         assert not serializer.is_valid()
         assert "non_field_errors" in serializer.errors
+
+
+class TestKubernetesProviderSecret:
+    def test_valid_static_kubeconfig_is_accepted(self):
+        kubeconfig_content = """
+apiVersion: v1
+kind: Config
+clusters:
+  - name: test-cluster
+    cluster:
+      server: https://kubernetes.example.test
+users:
+  - name: test-user
+    user:
+      token: test-token
+contexts:
+  - name: test-context
+    context:
+      cluster: test-cluster
+      user: test-user
+current-context: test-context
+"""
+
+        serializer = KubernetesProviderSecret(
+            data={"kubeconfig_content": kubeconfig_content}
+        )
+
+        assert serializer.is_valid()
+
+    def test_kubeconfig_with_exec_authentication_is_rejected(self):
+        kubeconfig_content = """
+apiVersion: v1
+kind: Config
+clusters:
+  - name: test-cluster
+    cluster:
+      server: https://kubernetes.example.test
+users:
+  - name: test-user
+    user:
+      exec:
+        apiVersion: client.authentication.k8s.io/v1
+        command: kubectl
+contexts:
+  - name: test-context
+    context:
+      cluster: test-cluster
+      user: test-user
+current-context: test-context
+"""
+
+        serializer = KubernetesProviderSecret(
+            data={"kubeconfig_content": kubeconfig_content}
+        )
+
+        assert not serializer.is_valid()
+        assert "kubeconfig_content" in serializer.errors
+
+    def test_malformed_kubeconfig_is_rejected(self):
+        serializer = KubernetesProviderSecret(
+            data={"kubeconfig_content": "apiVersion: ["}
+        )
+
+        assert not serializer.is_valid()
+        assert "kubeconfig_content" in serializer.errors
+
+    def test_non_mapping_kubeconfig_is_rejected(self):
+        serializer = KubernetesProviderSecret(data={"kubeconfig_content": "[]"})
+
+        assert not serializer.is_valid()
+        assert "kubeconfig_content" in serializer.errors

api/src/backend/api/tests/test_views.py

@@ -2960,7 +2960,24 @@ class TestProviderSecretViewSet:
                 Provider.ProviderChoices.KUBERNETES.value,
                 ProviderSecret.TypeChoices.STATIC,
                 {
-                    "kubeconfig_content": "kubeconfig-content",
+                    "kubeconfig_content": """
+apiVersion: v1
+kind: Config
+clusters:
+  - name: test-cluster
+    cluster:
+      server: https://kubernetes.example.test
+users:
+  - name: test-user
+    user:
+      token: test-token
+contexts:
+  - name: test-context
+    context:
+      cluster: test-cluster
+      user: test-user
+current-context: test-context
+""",
                 },
             ),
             # M365 client secret credentials

api/src/backend/api/v1/serializer_utils/providers.py

@@ -213,7 +213,8 @@ from rest_framework_json_api import serializers
                 "properties": {
                     "kubeconfig_content": {
                         "type": "string",
-                        "description": "The content of the Kubernetes kubeconfig file, encoded as a string.",
+                        "description": "The content of the Kubernetes kubeconfig file, encoded as a string. "
+                        "Kubeconfig exec authentication is not supported in Prowler Cloud for security reasons.",
                     }
                 },
                 "required": ["kubeconfig_content"],

api/src/backend/api/v1/serializers.py

@@ -2,6 +2,7 @@ import base64
 import json
 from datetime import UTC, datetime, timedelta
 
+import yaml
 from api.db_router import MainRouter
 from api.exceptions import ConflictException
 from api.models import (
@@ -1530,6 +1531,32 @@ class FindingMetadataSerializer(BaseSerializerV1):
 
 
 # Provider secrets
+KUBERNETES_KUBECONFIG_EXEC_ERROR = (
+    "Kubernetes kubeconfig exec authentication is not supported in Prowler Cloud "
+    "for security reasons."
+)
+KUBERNETES_KUBECONFIG_INVALID_ERROR = "Invalid Kubernetes kubeconfig content."
+
+
+def kubeconfig_contains_exec_auth(kubeconfig: dict) -> bool:
+    users = kubeconfig.get("users", [])
+    if not isinstance(users, list):
+        raise ValidationError(KUBERNETES_KUBECONFIG_INVALID_ERROR)
+
+    for user_entry in users:
+        if not isinstance(user_entry, dict):
+            raise ValidationError(KUBERNETES_KUBECONFIG_INVALID_ERROR)
+
+        user = user_entry.get("user", {})
+        if not isinstance(user, dict):
+            raise ValidationError(KUBERNETES_KUBECONFIG_INVALID_ERROR)
+
+        if "exec" in user:
+            return True
+
+    return False
+
+
 class BaseWriteProviderSecretSerializer(BaseWriteSerializer):
     @staticmethod
     def validate_secret_based_on_provider(
@@ -1711,6 +1738,22 @@ class MongoDBAtlasProviderSecret(serializers.Serializer):
 class KubernetesProviderSecret(serializers.Serializer):
     kubeconfig_content = serializers.CharField()
 
+    def validate_kubeconfig_content(self, kubeconfig_content):
+        try:
+            kubeconfig = yaml.safe_load(kubeconfig_content)
+        except yaml.YAMLError as exc:
+            raise serializers.ValidationError(
+                KUBERNETES_KUBECONFIG_INVALID_ERROR
+            ) from exc
+
+        if not isinstance(kubeconfig, dict):
+            raise serializers.ValidationError(KUBERNETES_KUBECONFIG_INVALID_ERROR)
+
+        if kubeconfig_contains_exec_auth(kubeconfig):
+            raise serializers.ValidationError(KUBERNETES_KUBECONFIG_EXEC_ERROR)
+
+        return kubeconfig_content
+
     class Meta:
         resource_name = "provider-secrets"
 

docs/user-guide/providers/kubernetes/getting-started-k8s.mdx

@@ -23,6 +23,10 @@ title: 'Getting Started with Kubernetes'
 
 For Kubernetes, Prowler App uses a `kubeconfig` file to authenticate. Paste the contents of your `kubeconfig` file into the `Kubeconfig content` field.
 
+<Note>
+Kubeconfigs that use `users[].user.exec` authentication are not supported in Prowler Cloud/App. For security reasons, Prowler Cloud does not run commands declared by uploaded kubeconfigs. Use kubeconfig credentials that do not rely on `exec` authentication, such as the ServiceAccount token flow documented below.
+</Note>
+
 By default, the `kubeconfig` file is located at `~/.kube/config`.
 
 ![Kubernetes Credentials](/images/kubernetes-credentials.png)

ui/CHANGELOG.md

@@ -20,6 +20,10 @@ All notable changes to the **Prowler UI** are documented in this file.
 
 - Invitation callback paths are now preserved when invited users continue with Google, GitHub, or SAML authentication [(#11752)](https://github.com/prowler-cloud/prowler/pull/11752)
 
+### 🔐 Security
+
+- Kubernetes provider credential forms now reject kubeconfigs using `exec` authentication in Prowler Cloud before submission [(#11753)](https://github.com/prowler-cloud/prowler/pull/11753)
+
 ---
 
 ## [1.32.0] (Prowler v5.32.0)

ui/components/providers/workflow/forms/via-credentials/k8s-credentials-form.tsx

@@ -1,13 +1,28 @@
+"use client";
+
 import { Control } from "react-hook-form";
+import { useWatch } from "react-hook-form";
 
 import { WizardTextareaField } from "@/components/providers/workflow/forms/fields";
 import { KubernetesCredentials } from "@/types";
+import {
+  KUBECONFIG_EXEC_AUTHENTICATION_ERROR,
+  kubeconfigContainsExecAuthentication,
+} from "@/types/formSchemas";
 
 export const KubernetesCredentialsForm = ({
   control,
 }: {
   control: Control<KubernetesCredentials>;
 }) => {
+  const kubeconfigContent = useWatch({
+    control,
+    name: "kubeconfig_content",
+  });
+  const hasExecAuthentication = kubeconfigContainsExecAuthentication(
+    kubeconfigContent ?? "",
+  );
+
   return (
     <>
       <div className="flex flex-col">
@@ -28,6 +43,11 @@ export const KubernetesCredentialsForm = ({
         minRows={10}
         isRequired
       />
+      {hasExecAuthentication && (
+        <p className="text-text-error-primary text-xs">
+          {KUBECONFIG_EXEC_AUTHENTICATION_ERROR}
+        </p>
+      )}
     </>
   );
 };

ui/types/formSchemas.test.ts

@@ -150,3 +150,73 @@ describe("addCredentialsFormSchema - okta", () => {
     );
   });
 });
+
+describe("addCredentialsFormSchema - kubernetes", () => {
+  const BASE_KUBERNETES_VALUES = {
+    [ProviderCredentialFields.PROVIDER_ID]: "provider-kubernetes-1",
+    [ProviderCredentialFields.PROVIDER_TYPE]: "kubernetes",
+  } as const;
+
+  it("accepts kubeconfig content without exec authentication", () => {
+    const schema = addCredentialsFormSchema("kubernetes");
+
+    const result = schema.safeParse({
+      ...BASE_KUBERNETES_VALUES,
+      [ProviderCredentialFields.KUBECONFIG_CONTENT]: `apiVersion: v1
+kind: Config
+users:
+  - name: test-user
+    user:
+      token: test-token`,
+    });
+
+    expect(result.success).toBe(true);
+  });
+
+  it("reports kubeconfig exec authentication on kubeconfig_content field", () => {
+    const schema = addCredentialsFormSchema("kubernetes");
+
+    const result = schema.safeParse({
+      ...BASE_KUBERNETES_VALUES,
+      [ProviderCredentialFields.KUBECONFIG_CONTENT]: `apiVersion: v1
+kind: Config
+users:
+  - name: test-user
+    user:
+      exec:
+        apiVersion: client.authentication.k8s.io/v1
+        command: kubectl`,
+    });
+
+    expect(result.success).toBe(false);
+    if (result.success) return;
+
+    expect(result.error.issues).toContainEqual(
+      expect.objectContaining({
+        path: [ProviderCredentialFields.KUBECONFIG_CONTENT],
+      }),
+    );
+  });
+
+  it("accepts malformed kubeconfig content for backend validation", () => {
+    const schema = addCredentialsFormSchema("kubernetes");
+
+    const result = schema.safeParse({
+      ...BASE_KUBERNETES_VALUES,
+      [ProviderCredentialFields.KUBECONFIG_CONTENT]: "apiVersion: [",
+    });
+
+    expect(result.success).toBe(true);
+  });
+
+  it("accepts non-mapping kubeconfig content for backend validation", () => {
+    const schema = addCredentialsFormSchema("kubernetes");
+
+    const result = schema.safeParse({
+      ...BASE_KUBERNETES_VALUES,
+      [ProviderCredentialFields.KUBECONFIG_CONTENT]: "[]",
+    });
+
+    expect(result.success).toBe(true);
+  });
+});

ui/types/formSchemas.ts

@@ -1,3 +1,4 @@
+import yaml from "js-yaml";
 import { z } from "zod";
 
 import { ProviderCredentialFields } from "@/lib/provider-credentials/provider-credential-fields";
@@ -5,6 +6,35 @@ import { validateMutelistYaml, validateYaml } from "@/lib/yaml";
 
 import { PROVIDER_TYPES, ProviderType } from "./providers";
 
+export const KUBECONFIG_EXEC_AUTHENTICATION_ERROR =
+  "Kubernetes kubeconfig exec authentication is not supported in Prowler Cloud for security reasons.";
+
+const isRecord = (value: unknown): value is Record<string, unknown> => {
+  return typeof value === "object" && value !== null && !Array.isArray(value);
+};
+
+export const kubeconfigContainsExecAuthentication = (
+  value: string,
+): boolean => {
+  try {
+    const parsed = yaml.load(value);
+
+    if (!isRecord(parsed) || !Array.isArray(parsed.users)) {
+      return false;
+    }
+
+    return parsed.users.some((userEntry) => {
+      if (!isRecord(userEntry) || !isRecord(userEntry.user)) {
+        return false;
+      }
+
+      return "exec" in userEntry.user;
+    });
+  } catch {
+    return false;
+  }
+};
+
 export const addRoleFormSchema = z.object({
   name: z.string().min(1, "Name is required"),
   manage_users: z.boolean().default(false),
@@ -207,7 +237,13 @@ export const addCredentialsFormSchema = (
               ? {
                   [ProviderCredentialFields.KUBECONFIG_CONTENT]: z
                     .string()
-                    .min(1, "Kubeconfig Content is required"),
+                    .min(1, "Kubeconfig Content is required")
+                    .refine(
+                      (value) => !kubeconfigContainsExecAuthentication(value),
+                      {
+                        error: KUBECONFIG_EXEC_AUTHENTICATION_ERROR,
+                      },
+                    ),
                 }
               : providerType === "m365"
                 ? {