diff --git a/Lib/unittest/mock.py b/Lib/unittest/mock.py
index 2719f74d6fca50..d3ea5a5614c4c7 100644
--- a/Lib/unittest/mock.py
+++ b/Lib/unittest/mock.py
@@ -496,9 +496,8 @@ def _mock_add_spec(self, spec, spec_set, _spec_as_instance=False,
         _spec_signature = None
         _spec_asyncs = []
 
-        for attr in dir(spec):
-            if iscoroutinefunction(getattr(spec, attr, None)):
-                _spec_asyncs.append(attr)
+        for attr, _ in inspect.getmembers_static(spec, iscoroutinefunction):
+            _spec_asyncs.append(attr)
 
         if spec is not None and not _is_list(spec):
             if isinstance(spec, type):
diff --git a/Lib/unittest/test/testmock/testmock.py b/Lib/unittest/test/testmock/testmock.py
index c99098dc4ea86a..aaac55c18d28dd 100644
--- a/Lib/unittest/test/testmock/testmock.py
+++ b/Lib/unittest/test/testmock/testmock.py
@@ -325,6 +325,20 @@ def test_call(self):
             "call_args_list not set")
 
 
+    def test_not_called_descriptor_protocol(self):
+        import types
+        class A:
+            @property
+            def name(self):
+                raise NotImplementedError
+            @types.DynamicClassAttribute
+            def eggs(self):
+                raise NotImplementedError
+
+        self.assertIsInstance(Mock(spec=A), A)
+        self.assertIsInstance(Mock(spec=A()), A)
+
+
     def test_call_args_comparison(self):
         mock = Mock()
         mock()
diff --git a/Misc/NEWS.d/next/Library/2022-02-15-14-29-41.bpo-45756.P0sGlU.rst b/Misc/NEWS.d/next/Library/2022-02-15-14-29-41.bpo-45756.P0sGlU.rst
new file mode 100644
index 00000000000000..92f942ebd0a346
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2022-02-15-14-29-41.bpo-45756.P0sGlU.rst
@@ -0,0 +1,2 @@
+Fix :mod:`unittest.mock` triggers dynamic lookup via the descriptor
+protocol. Patch by Weipeng Hong.