Refresh Token Reuse Protection (#1452)

* Implement REFRESH_TOKEN_REUSE_PROTECTION (#1404)

According to https://datatracker.ietf.org/doc/html/draft-ietf-oauth-security-topics-29#name-recommendations, the authorization server needs a way to determine which refresh tokens belong to the same session, so it is able to figure out which tokens to revoke. Therefore, this commit introduces a "token_family" field to the RefreshToken table. Whenever a revoked refresh token is reused, the auth server uses the token family to revoke all related tokens.

AUTHORS

@@ -105,6 +105,7 @@ Shaheed Haque
 Shaun Stanworth
 Silvano Cerza
 Sora Yanai
+Sören Wegener
 Spencer Carroll
 Stéphane Raimbault
 Tom Evans

CHANGELOG.md

@@ -16,6 +16,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [unreleased]
 ### Added
+* #1404 Add a new setting `REFRESH_TOKEN_REUSE_PROTECTION`
 ### Changed
 ### Deprecated
 ### Removed

docs/settings.rst

@@ -185,6 +185,18 @@ The import string of the class (model) representing your refresh tokens. Overwri
 this value if you wrote your own implementation (subclass of
 ``oauth2_provider.models.RefreshToken``).
 
+REFRESH_TOKEN_REUSE_PROTECTION
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+When this is set to ``True`` (default ``False``), and ``ROTATE_REFRESH_TOKEN`` is used, the server will check
+if a previously, already revoked refresh token is used a second time. If it detects a reuse, it will automatically
+revoke all related refresh tokens.
+A reused refresh token indicates a breach. Since the server can't determine which request came from the legitimate
+user and which from an attacker, it will end the session for both. The user is required to perform a new login.
+
+Can be used in combination with ``REFRESH_TOKEN_GRACE_PERIOD_SECONDS``
+
+More details at https://datatracker.ietf.org/doc/html/draft-ietf-oauth-security-topics-29#name-recommendations
+
 ROTATE_REFRESH_TOKEN
 ~~~~~~~~~~~~~~~~~~~~
 When is set to ``True`` (default) a new refresh token is issued to the client when the client refreshes an access token.

oauth2_provider/migrations/0011_refreshtoken_token_family.py

@@ -0,0 +1,19 @@
+# Generated by Django 5.2 on 2024-08-09 16:40
+
+from django.db import migrations, models
+from oauth2_provider.settings import oauth2_settings
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('oauth2_provider', '0010_application_allowed_origins'),
+        migrations.swappable_dependency(oauth2_settings.REFRESH_TOKEN_MODEL)
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='refreshtoken',
+            name='token_family',
+            field=models.UUIDField(blank=True, editable=False, null=True),
+        ),
+    ]

oauth2_provider/models.py

@@ -490,6 +490,7 @@ class AbstractRefreshToken(models.Model):
         null=True,
         related_name="refresh_token",
     )
+    token_family = models.UUIDField(null=True, blank=True, editable=False)
 
     created = models.DateTimeField(auto_now_add=True)
     updated = models.DateTimeField(auto_now=True)

oauth2_provider/oauth2_validators.py

@@ -15,7 +15,6 @@
 from django.contrib.auth.hashers import check_password, identify_hasher
 from django.core.exceptions import ObjectDoesNotExist
 from django.db import transaction
-from django.db.models import Q
 from django.http import HttpRequest
 from django.utils import dateformat, timezone
 from django.utils.crypto import constant_time_compare
@@ -644,7 +643,9 @@ def save_bearer_token(self, token, request, *args, **kwargs):
                         source_refresh_token=refresh_token_instance,
                     )
 
-                    self._create_refresh_token(request, refresh_token_code, access_token)
+                    self._create_refresh_token(
+                        request, refresh_token_code, access_token, refresh_token_instance
+                    )
                 else:
                     # make sure that the token data we're returning matches
                     # the existing token
@@ -688,9 +689,17 @@ def _create_authorization_code(self, request, code, expires=None):
             claims=json.dumps(request.claims or {}),
         )
 
-    def _create_refresh_token(self, request, refresh_token_code, access_token):
+    def _create_refresh_token(self, request, refresh_token_code, access_token, previous_refresh_token):
+        if previous_refresh_token:
+            token_family = previous_refresh_token.token_family
+        else:
+            token_family = uuid.uuid4()
         return RefreshToken.objects.create(
-            user=request.user, token=refresh_token_code, application=request.client, access_token=access_token
+            user=request.user,
+            token=refresh_token_code,
+            application=request.client,
+            access_token=access_token,
+            token_family=token_family,
         )
 
     def revoke_token(self, token, token_type_hint, request, *args, **kwargs):
@@ -752,22 +761,25 @@ def validate_refresh_token(self, refresh_token, client, request, *args, **kwargs
         Also attach User instance to the request object
         """
 
-        null_or_recent = Q(revoked__isnull=True) | Q(
-            revoked__gt=timezone.now() - timedelta(seconds=oauth2_settings.REFRESH_TOKEN_GRACE_PERIOD_SECONDS)
-        )
-        rt = (
-            RefreshToken.objects.filter(null_or_recent, token=refresh_token)
-            .select_related("access_token")
-            .first()
-        )
+        rt = RefreshToken.objects.filter(token=refresh_token).select_related("access_token").first()
 
         if not rt:
             return False
 
+        if rt.revoked is not None and rt.revoked <= timezone.now() - timedelta(
+            seconds=oauth2_settings.REFRESH_TOKEN_GRACE_PERIOD_SECONDS
+        ):
+            if oauth2_settings.REFRESH_TOKEN_REUSE_PROTECTION and rt.token_family:
+                rt_token_family = RefreshToken.objects.filter(token_family=rt.token_family)
+                for related_rt in rt_token_family.all():
+                    related_rt.revoke()
+            return False
+
         request.user = rt.user
         request.refresh_token = rt.token
         # Temporary store RefreshToken instance to be reused by get_original_scopes and save_bearer_token.
         request.refresh_token_instance = rt
+
         return rt.application == client
 
     @transaction.atomic

oauth2_provider/settings.py

@@ -54,6 +54,7 @@
     "ID_TOKEN_EXPIRE_SECONDS": 36000,
     "REFRESH_TOKEN_EXPIRE_SECONDS": None,
     "REFRESH_TOKEN_GRACE_PERIOD_SECONDS": 0,
+    "REFRESH_TOKEN_REUSE_PROTECTION": False,
     "ROTATE_REFRESH_TOKEN": True,
     "ERROR_RESPONSE_WITH_SCOPES": False,
     "APPLICATION_MODEL": APPLICATION_MODEL,

tests/migrations/0006_basetestapplication_token_family.py

@@ -0,0 +1,20 @@
+# Generated by Django 5.2 on 2024-08-09 16:40
+
+from django.db import migrations, models
+from oauth2_provider.settings import oauth2_settings
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('tests', '0005_basetestapplication_allowed_origins_and_more'),
+        migrations.swappable_dependency(oauth2_settings.REFRESH_TOKEN_MODEL)
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='samplerefreshtoken',
+            name='token_family',
+            field=models.UUIDField(blank=True, editable=False, null=True),
+        ),
+    ]

tests/test_authorization_code.py

@@ -985,6 +985,54 @@ def test_refresh_fail_repeating_requests(self):
         response = self.client.post(reverse("oauth2_provider:token"), data=token_request_data, **auth_headers)
         self.assertEqual(response.status_code, 400)
 
+    def test_refresh_repeating_requests_revokes_old_token(self):
+        """
+        If a refresh token is reused, the server should invalidate *all* access tokens that have a relation
+        to the re-used token. This forces a malicious actor to be logged out.
+        The server can't determine whether the first or the second client was legitimate, so it needs to
+        revoke both.
+        See https://datatracker.ietf.org/doc/html/draft-ietf-oauth-security-topics-29#name-recommendations
+        """
+        self.oauth2_settings.REFRESH_TOKEN_REUSE_PROTECTION = True
+        self.client.login(username="test_user", password="123456")
+        authorization_code = self.get_auth()
+
+        token_request_data = {
+            "grant_type": "authorization_code",
+            "code": authorization_code,
+            "redirect_uri": "http://example.org",
+        }
+        auth_headers = get_basic_auth_header(self.application.client_id, CLEARTEXT_SECRET)
+
+        response = self.client.post(reverse("oauth2_provider:token"), data=token_request_data, **auth_headers)
+        content = json.loads(response.content.decode("utf-8"))
+        self.assertTrue("refresh_token" in content)
+
+        token_request_data = {
+            "grant_type": "refresh_token",
+            "refresh_token": content["refresh_token"],
+            "scope": content["scope"],
+        }
+        # First response works as usual
+        response = self.client.post(reverse("oauth2_provider:token"), data=token_request_data, **auth_headers)
+        self.assertEqual(response.status_code, 200)
+        new_tokens = json.loads(response.content.decode("utf-8"))
+
+        # Second request fails
+        response = self.client.post(reverse("oauth2_provider:token"), data=token_request_data, **auth_headers)
+        self.assertEqual(response.status_code, 400)
+
+        # Previously returned tokens are now invalid as well
+        new_token_request_data = {
+            "grant_type": "refresh_token",
+            "refresh_token": new_tokens["refresh_token"],
+            "scope": new_tokens["scope"],
+        }
+        response = self.client.post(
+            reverse("oauth2_provider:token"), data=new_token_request_data, **auth_headers
+        )
+        self.assertEqual(response.status_code, 400)
+
     def test_refresh_repeating_requests(self):
         """
         Trying to refresh an access token with the same refresh token more than
@@ -1024,6 +1072,63 @@ def test_refresh_repeating_requests(self):
         response = self.client.post(reverse("oauth2_provider:token"), data=token_request_data, **auth_headers)
         self.assertEqual(response.status_code, 400)
 
+    def test_refresh_repeating_requests_grace_period_with_reuse_protection(self):
+        """
+        Trying to refresh an access token with the same refresh token more than
+        once succeeds. Should work within the grace period, but should revoke previous tokens
+        """
+        self.oauth2_settings.REFRESH_TOKEN_GRACE_PERIOD_SECONDS = 120
+        self.oauth2_settings.REFRESH_TOKEN_REUSE_PROTECTION = True
+        self.client.login(username="test_user", password="123456")
+        authorization_code = self.get_auth()
+
+        token_request_data = {
+            "grant_type": "authorization_code",
+            "code": authorization_code,
+            "redirect_uri": "http://example.org",
+        }
+        auth_headers = get_basic_auth_header(self.application.client_id, CLEARTEXT_SECRET)
+
+        response = self.client.post(reverse("oauth2_provider:token"), data=token_request_data, **auth_headers)
+        content = json.loads(response.content.decode("utf-8"))
+        self.assertTrue("refresh_token" in content)
+
+        refresh_token_1 = content["refresh_token"]
+        token_request_data = {
+            "grant_type": "refresh_token",
+            "refresh_token": refresh_token_1,
+            "scope": content["scope"],
+        }
+        response = self.client.post(reverse("oauth2_provider:token"), data=token_request_data, **auth_headers)
+        self.assertEqual(response.status_code, 200)
+        refresh_token_2 = json.loads(response.content.decode("utf-8"))["refresh_token"]
+
+        response = self.client.post(reverse("oauth2_provider:token"), data=token_request_data, **auth_headers)
+        self.assertEqual(response.status_code, 200)
+        refresh_token_3 = json.loads(response.content.decode("utf-8"))["refresh_token"]
+
+        self.assertEqual(refresh_token_2, refresh_token_3)
+
+        # Let the first refresh token expire
+        rt = RefreshToken.objects.get(token=refresh_token_1)
+        rt.revoked = timezone.now() - datetime.timedelta(minutes=10)
+        rt.save()
+
+        # Using the expired token fails
+        response = self.client.post(reverse("oauth2_provider:token"), data=token_request_data, **auth_headers)
+        self.assertEqual(response.status_code, 400)
+
+        # Because we used the expired token, the recently issued token is also revoked
+        new_token_request_data = {
+            "grant_type": "refresh_token",
+            "refresh_token": refresh_token_2,
+            "scope": content["scope"],
+        }
+        response = self.client.post(
+            reverse("oauth2_provider:token"), data=new_token_request_data, **auth_headers
+        )
+        self.assertEqual(response.status_code, 400)
+
     def test_refresh_repeating_requests_non_rotating_tokens(self):
         """
         Try refreshing an access token with the same refresh token more than once when not rotating tokens.