security: fix CVE-2024-47070 (#11536)

* security: fix CVE-2024-47070

Signed-off-by: Jens Langhammer <jens@goauthentik.io>

* Update website/docs/security/CVE-2024-47070.md

Co-authored-by: Tana M Berry <tanamarieberry@yahoo.com>
Signed-off-by: Jens L. <jens@beryju.org>

---------

Signed-off-by: Jens Langhammer <jens@goauthentik.io>
Signed-off-by: Jens L. <jens@beryju.org>
Co-authored-by: Tana M Berry <tanamarieberry@yahoo.com>

authentik/lib/tests/test_http.py

@@ -30,6 +30,11 @@ class TestHTTP(TestCase):
         request = self.factory.get("/", HTTP_X_FORWARDED_FOR="127.0.0.2")
         self.assertEqual(ClientIPMiddleware.get_client_ip(request), "127.0.0.2")
 
+    def test_forward_for_invalid(self):
+        """Test invalid forward for"""
+        request = self.factory.get("/", HTTP_X_FORWARDED_FOR="foobar")
+        self.assertEqual(ClientIPMiddleware.get_client_ip(request), ClientIPMiddleware.default_ip)
+
     def test_fake_outpost(self):
         """Test faked IP which is overridden by an outpost"""
         token = Token.objects.create(
@@ -53,6 +58,17 @@ class TestHTTP(TestCase):
             },
         )
         self.assertEqual(ClientIPMiddleware.get_client_ip(request), "127.0.0.1")
+        # Invalid, not a real IP
+        self.user.type = UserTypes.INTERNAL_SERVICE_ACCOUNT
+        self.user.save()
+        request = self.factory.get(
+            "/",
+            **{
+                ClientIPMiddleware.outpost_remote_ip_header: "foobar",
+                ClientIPMiddleware.outpost_token_header: token.key,
+            },
+        )
+        self.assertEqual(ClientIPMiddleware.get_client_ip(request), "127.0.0.1")
         # Valid
         self.user.type = UserTypes.INTERNAL_SERVICE_ACCOUNT
         self.user.save()

authentik/root/middleware.py

@@ -2,6 +2,7 @@
 
 from collections.abc import Callable
 from hashlib import sha512
+from ipaddress import ip_address
 from time import perf_counter, time
 from typing import Any
 
@@ -174,6 +175,7 @@ class ClientIPMiddleware:
 
     def __init__(self, get_response: Callable[[HttpRequest], HttpResponse]):
         self.get_response = get_response
+        self.logger = get_logger().bind()
 
     def _get_client_ip_from_meta(self, meta: dict[str, Any]) -> str:
         """Attempt to get the client's IP by checking common HTTP Headers.
@@ -185,11 +187,16 @@ class ClientIPMiddleware:
             "HTTP_X_FORWARDED_FOR",
             "REMOTE_ADDR",
         )
-        for _header in headers:
-            if _header in meta:
-                ips: list[str] = meta.get(_header).split(",")
-                return ips[0].strip()
-        return self.default_ip
+        try:
+            for _header in headers:
+                if _header in meta:
+                    ips: list[str] = meta.get(_header).split(",")
+                    # Ensure the IP parses as a valid IP
+                    return str(ip_address(ips[0].strip()))
+            return self.default_ip
+        except ValueError as exc:
+            self.logger.debug("Invalid remote IP", exc=exc)
+            return self.default_ip
 
     # FIXME: this should probably not be in `root` but rather in a middleware in `outposts`
     # but for now it's fine
@@ -226,7 +233,11 @@ class ClientIPMiddleware:
         Scope.get_isolation_scope().set_user(sentry_user)
         # Set the outpost service account on the request
         setattr(request, self.request_attr_outpost_user, user)
-        return delegated_ip
+        try:
+            return str(ip_address(delegated_ip))
+        except ValueError as exc:
+            self.logger.debug("Invalid remote IP from Outpost", exc=exc)
+            return None
 
     def _get_client_ip(self, request: HttpRequest | None) -> str:
         """Attempt to get the client's IP by checking common HTTP Headers.

blueprints/default/flow-default-authentication-flow.yaml

@@ -82,3 +82,5 @@ entries:
     order: 10
     target: !KeyOf default-authentication-flow-password-binding
     policy: !KeyOf default-authentication-flow-password-optional
+  attrs:
+    failure_result: true

website/docs/security/CVE-2024-42490.md

@@ -2,7 +2,7 @@
 
 _Reported by [@m2a2](https://github.com/m2a2)_
 
-## Improper Authorization for Token modification
+## Insufficient Authorization for several API endpoints
 
 ### Summary
 

website/docs/security/CVE-2024-47070.md

@@ -0,0 +1,35 @@
+# CVE-2024-47070
+
+_Reported by [@efpi-bot](https://github.com/efpi-bot) from [LogicalTrust](https://logicaltrust.net/en/)_
+
+## Password authentication bypass via X-Forwarded-For HTTP header
+
+### Summary
+
+The vulnerability allows bypassing policies by adding X-Forwarded-For header with unparsable IP address, e.g. "a". This results in a possibility to authenticate/authorize to any account with known login or email address.
+
+Since the default authentication flow uses a policy to enable the password stage only when there is no password stage selected on the Identification stage, this vulnerability can be used to skip this policy and continue without the password stage.
+
+### Am I affected
+
+This can be exploited for the following configurations:
+
+-   An attacker can access authentik without a reverse proxy (and `AUTHENTIK_LISTEN__TRUSTED_PROXY_CIDRS` is not configured properly)
+-   The reverse proxy configuration does not correctly overwrite X-Forwarded-For
+-   Policies (User and group bindings do _not_ apply) are bound to authentication/authorization flows
+
+### Patches
+
+authentik 2024.6.5 and 2024.8.3 fix this issue.
+
+### Workarounds
+
+Ensure the X-Forwarded-For header is always set by the reverse proxy, and is always set to a correct IP.
+
+In addition you can manually change the _Failure result_ option on policy bindings to _Pass_, which will prevent any stages from being skipped if a malicious request is received.
+
+### For more information
+
+If you have any questions or comments about this advisory:
+
+-   Email us at [security@goauthentik.io](mailto:security@goauthentik.io)

website/sidebars.js

@@ -522,6 +522,7 @@ const docsSidebar = {
                 "security/security-hardening",
                 "security/policy",
                 "security/CVE-2024-47077",
+                "security/CVE-2024-47070",
                 "security/CVE-2024-42490",
                 "security/CVE-2024-38371",
                 "security/CVE-2024-37905",