diff --git a/tests/data/stubs/stub-sudo.py b/tests/data/stubs/stub-sudo.py
index a7f2704f..71364df7 100755
--- a/tests/data/stubs/stub-sudo.py
+++ b/tests/data/stubs/stub-sudo.py
@@ -8,7 +8,12 @@ import sys
 os.environ['ORIGINAL_ARGV'] = json.dumps(sys.argv)
 os.environ['THIS_IS_STUB_SUDO'] = '1'
 
-# This must be a child process and not exec() since Mitogen replaces its stderr
-# descriptor, causing the last user of the slave PTY to close it, resulting in
-# the master side indicating EIO.
-subprocess.check_call(sys.argv[sys.argv.index('--') + 1:])
+if os.environ.get('PREHISTORIC_SUDO'):
+    # issue #481: old versions of sudo did in fact use execve, thus we must
+    # have TTY handle preservation in core.py.
+    os.execv(sys.executable, sys.argv[sys.argv.index('--') + 1:])
+else:
+    # This must be a child process and not exec() since Mitogen replaces its
+    # stderr descriptor, causing the last user of the slave PTY to close it,
+    # resulting in the master side indicating EIO.
+    subprocess.check_call(sys.argv[sys.argv.index('--') + 1:])
diff --git a/tests/sudo_test.py b/tests/sudo_test.py
index 5bf9f4de..1d10ba9a 100644
--- a/tests/sudo_test.py
+++ b/tests/sudo_test.py
@@ -55,6 +55,15 @@ class ConstructorTest(testlib.RouterMixin, testlib.TestCase):
             '--'
         ])
 
+    def test_tty_preserved(self):
+        # issue #481
+        os.environ['PREHISTORIC_SUDO'] = '1'
+        try:
+            context, argv = self.run_sudo()
+            self.assertEquals('1', context.call(os.getenv, 'PREHISTORIC_SUDO'))
+        finally:
+            del os.environ['PREHISTORIC_SUDO']
+
 
 class NonEnglishPromptTest(testlib.DockerMixin, testlib.TestCase):
     # Only mitogen/debian-test has a properly configured sudo.