fix: remove pickle hasattr allowlist entries

CHANGELOG.md

@@ -82,6 +82,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Fixed
 
 - **security:** treat legacy `httplib` pickle globals the same as `http.client`, including import-only and `REDUCE` findings in standalone and archived payloads
+- **security:** remove `builtins.hasattr` / `__builtin__.hasattr` from the pickle safe-global allowlist so attribute-access primitives stay flagged as dangerous builtins
 - **security:** harden TensorFlow weight extraction limits to bound actual tensor payload materialization, including malformed `tensor_content` and string-backed tensors, and continue scanning past oversized `Const` nodes
 - **security:** stream TAR members to temp files under size limits instead of buffering whole entries in memory during scan
 - **security:** inspect TensorFlow SavedModel function definitions when scanning for dangerous ops and protobuf string abuse, with function-aware finding locations

modelaudit/scanners/pickle_scanner.py

@@ -716,7 +716,8 @@ def _is_dangerous_module(mod: str) -> bool:
     ],
     # Python builtins - safe built-in types and functions
     # NOTE: eval, exec, compile, __import__, open, file are NOT in this list (they remain dangerous)
-    # NOTE: getattr, setattr, delattr are also NOT in this list (in ALWAYS_DANGEROUS_FUNCTIONS)
+    # NOTE: getattr, setattr, delattr, hasattr are NOT in this list
+    # because attribute-access primitives must never be allowlisted.
     "__builtin__": [  # Python 2 builtins
         "set",
         "frozenset",
@@ -751,7 +752,6 @@ def _is_dangerous_module(mod: str) -> bool:
         "id",
         "isinstance",
         "issubclass",
-        "hasattr",
         "callable",
         "repr",
         "ascii",
@@ -811,7 +811,6 @@ def _is_dangerous_module(mod: str) -> bool:
         "id",
         "isinstance",
         "issubclass",
-        "hasattr",
         "callable",
         "repr",
         "ascii",

tests/scanners/test_pickle_scanner.py

@@ -659,6 +659,142 @@ def _scan_bytes(self, data: bytes) -> ScanResult:
         finally:
             os.unlink(path)
 
+    def test_builtins_hasattr_is_critical(self) -> None:
+        """builtins.hasattr must not be allowlisted as safe."""
+        result = self._scan_bytes(self._craft_global_reduce_pickle("builtins", "hasattr"))
+
+        assert result.success
+        assert result.has_errors
+        failed_global_checks = [
+            check
+            for check in result.checks
+            if check.name == "Global Module Reference Check"
+            and check.status == CheckStatus.FAILED
+            and check.severity == IssueSeverity.CRITICAL
+        ]
+        assert any("builtins.hasattr" in check.message for check in failed_global_checks), (
+            f"Expected CRITICAL Global Module Reference Check for builtins.hasattr, "
+            f"got: {[check.message for check in failed_global_checks]}"
+        )
+
+    def test_dunder_builtin_hasattr_is_critical(self) -> None:
+        """__builtin__.hasattr must not be allowlisted as safe."""
+        result = self._scan_bytes(self._craft_global_reduce_pickle("__builtin__", "hasattr"))
+
+        assert result.success
+        assert result.has_errors
+        failed_global_checks = [
+            check
+            for check in result.checks
+            if check.name == "Global Module Reference Check"
+            and check.status == CheckStatus.FAILED
+            and check.severity == IssueSeverity.CRITICAL
+        ]
+        assert any("__builtin__.hasattr" in check.message for check in failed_global_checks), (
+            f"Expected CRITICAL Global Module Reference Check for __builtin__.hasattr, "
+            f"got: {[check.message for check in failed_global_checks]}"
+        )
+
+    def test_safe_builtins_remain_allowlisted(self) -> None:
+        """Safe reconstruction builtins must remain non-failing."""
+        for safe_builtin in ["set", "slice", "tuple"]:
+            result = self._scan_bytes(self._craft_global_reduce_pickle("builtins", safe_builtin))
+
+            assert result.success
+            assert not result.has_errors, (
+                f"Expected builtins.{safe_builtin} to remain non-failing, got: {[i.message for i in result.issues]}"
+            )
+            safe_global_checks = [check for check in result.checks if check.name == "Global Module Reference Check"]
+            assert any(
+                check.status == CheckStatus.PASSED and f"builtins.{safe_builtin}" in check.message
+                for check in safe_global_checks
+            ), f"Expected passed Global Module Reference Check for builtins.{safe_builtin}"
+            assert not any(check.status == CheckStatus.FAILED for check in safe_global_checks), (
+                f"Unexpected failed Global Module Reference Check for builtins.{safe_builtin}: "
+                f"{[check.message for check in safe_global_checks]}"
+            )
+
+    def test_dangerous_builtins_still_fail(self) -> None:
+        """Dangerous builtins must continue to fail after allowlist tightening."""
+        for dangerous_builtin in ["eval", "open"]:
+            result = self._scan_bytes(self._craft_global_reduce_pickle("builtins", dangerous_builtin))
+
+            assert result.success
+            assert result.has_errors
+            failed_checks = [
+                check
+                for check in result.checks
+                if check.status == CheckStatus.FAILED and check.severity == IssueSeverity.CRITICAL
+            ]
+            assert any(f"builtins.{dangerous_builtin}" in check.message for check in failed_checks), (
+                f"Expected CRITICAL builtins.{dangerous_builtin} finding, "
+                f"got: {[check.message for check in failed_checks]}"
+            )
+
+    def test_builtins_hasattr_stack_global_is_critical(self) -> None:
+        """STACK_GLOBAL resolution for builtins.hasattr must be flagged."""
+        payload = b"\x80\x04\x8c\x08builtins\x8c\x07hasattr\x93)R."
+
+        result = self._scan_bytes(payload)
+
+        assert result.success
+        assert result.has_errors
+        failed_stack_global_checks = [
+            check
+            for check in result.checks
+            if check.name == "STACK_GLOBAL Module Check"
+            and check.status == CheckStatus.FAILED
+            and check.severity == IssueSeverity.CRITICAL
+        ]
+        assert any("builtins.hasattr" in check.message for check in failed_stack_global_checks), (
+            f"Expected CRITICAL STACK_GLOBAL Module Check for builtins.hasattr, "
+            f"got: {[check.message for check in failed_stack_global_checks]}"
+        )
+
+    def test_builtins_hasattr_binput_binget_recall_is_critical(self) -> None:
+        """Memoized callable recall via BINPUT/BINGET must keep builtins.hasattr dangerous."""
+        payload = b"\x80\x02cbuiltins\nhasattr\nq\x01h\x01(tR."
+
+        result = self._scan_bytes(payload)
+
+        assert result.success
+        assert result.has_errors
+        failed_reduce_checks = [
+            check
+            for check in result.checks
+            if check.name == "REDUCE Opcode Safety Check"
+            and check.status == CheckStatus.FAILED
+            and check.severity == IssueSeverity.CRITICAL
+        ]
+        assert any(check.details.get("associated_global") == "builtins.hasattr" for check in failed_reduce_checks), (
+            f"Expected CRITICAL REDUCE finding for builtins.hasattr memo recall, "
+            f"got: {[check.details for check in failed_reduce_checks]}"
+        )
+
+    def test_builtins_hasattr_detected_after_benign_stream(self) -> None:
+        """Malicious builtins.hasattr stream should be detected after benign warm-up stream."""
+        import io
+
+        buf = io.BytesIO()
+        pickle.dump({"safe": True}, buf, protocol=2)
+        buf.write(self._craft_global_reduce_pickle("builtins", "hasattr"))
+
+        result = self._scan_bytes(buf.getvalue())
+
+        assert result.success
+        assert result.has_errors
+        failed_reduce_checks = [
+            check
+            for check in result.checks
+            if check.name == "REDUCE Opcode Safety Check"
+            and check.status == CheckStatus.FAILED
+            and check.severity == IssueSeverity.CRITICAL
+        ]
+        assert any(check.details.get("associated_global") == "builtins.hasattr" for check in failed_reduce_checks), (
+            f"Expected CRITICAL REDUCE finding for builtins.hasattr after benign stream, "
+            f"got: {[check.details for check in failed_reduce_checks]}"
+        )
+
     # ------------------------------------------------------------------
     # Fix 1: pkgutil trampoline — must be CRITICAL
     # ------------------------------------------------------------------