diff --git a/src/scmrepo/git/backend/dulwich/asyncssh_vendor.py b/src/scmrepo/git/backend/dulwich/asyncssh_vendor.py
index 93360441..b0a0c311 100644
--- a/src/scmrepo/git/backend/dulwich/asyncssh_vendor.py
+++ b/src/scmrepo/git/backend/dulwich/asyncssh_vendor.py
@@ -298,7 +298,7 @@ async def _run_command(
                 host,
                 port=port if port is not None else (),
                 username=username if username is not None else (),
-                password=password if password is not None else (),
+                password=password,
                 client_keys=[key_filename] if key_filename else (),
                 ignore_encrypted=not key_filename,
                 known_hosts=None,
diff --git a/tests/test_dulwich.py b/tests/test_dulwich.py
index 80195269..c9305eee 100644
--- a/tests/test_dulwich.py
+++ b/tests/test_dulwich.py
@@ -11,18 +11,74 @@
 from pytest_mock import MockerFixture
 from pytest_test_utils.waiters import wait_until
 
+from scmrepo.exceptions import AuthError
 from scmrepo.git.backend.dulwich.asyncssh_vendor import AsyncSSHVendor
 
-from .vendor.test_paramiko_vendor import (
-    CLIENT_KEY,
-    PASSWORD,
-    USER,
-    Server,
-)
-
 # pylint: disable=redefined-outer-name
 
 
+USER = "testuser"
+PASSWORD = "test"
+CLIENT_KEY = """-----BEGIN RSA PRIVATE KEY-----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+-----END RSA PRIVATE KEY-----"""
+
+
+class Server(paramiko.ServerInterface):
+    """http://docs.paramiko.org/en/2.4/api/server.html."""
+
+    def __init__(self, commands, *args, **kwargs) -> None:
+        super().__init__(*args, **kwargs)
+        self.commands = commands
+
+    def check_channel_exec_request(self, channel, command):
+        self.commands.append(command)
+        return True
+
+    def check_auth_password(self, username, password):
+        if username == USER and password == PASSWORD:
+            return paramiko.AUTH_SUCCESSFUL
+        return paramiko.AUTH_FAILED
+
+    def check_auth_publickey(self, username, key):
+        pubkey = paramiko.RSAKey.from_private_key(StringIO(CLIENT_KEY))
+        if username == USER and key == pubkey:
+            return paramiko.AUTH_SUCCESSFUL
+        return paramiko.AUTH_FAILED
+
+    def check_channel_request(self, kind, chanid):
+        if kind == "session":
+            return paramiko.OPEN_SUCCEEDED
+        return paramiko.OPEN_FAILED_ADMINISTRATIVELY_PROHIBITED
+
+    def get_allowed_auths(self, username):
+        return "password,publickey"
+
+
 @pytest.fixture
 def ssh_conn(request: pytest.FixtureRequest) -> dict[str, Any]:
     server = Server([])
@@ -77,6 +133,18 @@ def test_run_command_password(server: Server, ssh_port: int):
     assert b"test_run_command_password" in server.commands
 
 
+def test_run_command_no_password(server: Server, ssh_port: int):
+    vendor = AsyncSSHVendor()
+    with pytest.raises(AuthError):
+        vendor.run_command(
+            "127.0.0.1",
+            "test_run_command_password",
+            username=USER,
+            port=ssh_port,
+            password=None,
+        )
+
+
 def test_run_command_with_privkey(server: Server, ssh_port: int):
     key = asyncssh.import_private_key(CLIENT_KEY)