diff --git a/src/com/android/server/telecom/TelecomServiceImpl.java b/src/com/android/server/telecom/TelecomServiceImpl.java
index 61fa9ba..313a164 100644
--- a/src/com/android/server/telecom/TelecomServiceImpl.java
+++ b/src/com/android/server/telecom/TelecomServiceImpl.java
@@ -787,6 +787,9 @@
                         Bundle extras = account.getExtras();
                         if (extras != null
                                 && extras.getBoolean(PhoneAccount.EXTRA_SKIP_CALL_FILTERING)) {
+                            // System apps should be granted the MODIFY_PHONE_STATE permission.
+                            enforceModifyPermission(
+                                    "registerPhoneAccount requires MODIFY_PHONE_STATE permission.");
                             enforceRegisterSkipCallFiltering();
                         }
                         final int callingUid = Binder.getCallingUid();