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Python library for Windows Remote Management

Project description


pywinrm is a Python client for the Windows Remote Management (WinRM) service. It allows you to invoke commands on target Windows machines from any machine that can run Python.

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WinRM allows you to perform various management tasks remotely. These include, but are not limited to: running batch scripts, powershell scripts, and fetching WMI variables.

Used by Ansible for Windows support.

For more information on WinRM, please visit Microsoft's WinRM site.



To install pywinrm with support for basic, certificate, and NTLM auth, simply

$ pip install pywinrm

To use Kerberos authentication you need these optional dependencies

# for Debian/Ubuntu/etc:
$ sudo apt-get install gcc python-dev libkrb5-dev
$ pip install pywinrm[kerberos]

# for RHEL/CentOS/etc:
$ sudo yum install gcc python-devel krb5-devel krb5-workstation python-devel
$ pip install pywinrm[kerberos]

To use CredSSP authentication you need these optional dependencies

# for Debian/Ubuntu/etc:
$ sudo apt-get install gcc python-dev libssl-dev
$ pip install pywinrm[credssp]

# for RHEL/CentOS/etc:
$ sudo yum install gcc python-devel openssl-devel
$ pip install pywinrm[credssp]

Example Usage

Run a process on a remote host

import winrm

s = winrm.Session('', auth=('john.smith', 'secret'))
r = s.run_cmd('ipconfig', ['/all'])
>>> r.status_code
>>> r.std_out
Windows IP Configuration

   Host Name . . . . . . . . . . . . : WINDOWS-HOST
   Primary Dns Suffix  . . . . . . . :
   Node Type . . . . . . . . . . . . : Hybrid
   IP Routing Enabled. . . . . . . . : No
   WINS Proxy Enabled. . . . . . . . : No
>>> r.std_err

NOTE: pywinrm will try and guess the correct endpoint url from the following formats:

Run Powershell script on remote host

import winrm

ps_script = """$strComputer = $Host
$RAM = WmiObject Win32_ComputerSystem
$MB = 1048576

"Installed Memory: " + [int]($RAM.TotalPhysicalMemory /$MB) + " MB" """

s = winrm.Session('', auth=('john.smith', 'secret'))
r = s.run_ps(ps_script)
>>> r.status_code
>>> r.std_out
Installed Memory: 3840 MB

>>> r.std_err

Powershell scripts will be base64 UTF16 little-endian encoded prior to sending to the Windows host. Error messages are converted from the Powershell CLIXML format to a human readable format as a convenience.

Run process with low-level API with domain user, disabling HTTPS cert validation

from winrm.protocol import Protocol

p = Protocol(
shell_id = p.open_shell()
command_id = p.run_command(shell_id, 'ipconfig', ['/all'])
std_out, std_err, status_code = p.get_command_output(shell_id, command_id)
p.cleanup_command(shell_id, command_id)

Valid transport options

pywinrm supports various transport methods in order to authenticate with the WinRM server. The options that are supported in the transport parameter are;

  • basic: Basic auth only works for local Windows accounts not domain accounts. Credentials are base64 encoded when sending to the server.
  • plaintext: Same as basic auth.
  • certificate: Authentication is done through a certificate that is mapped to a local Windows account on the server.
  • ssl: When used in conjunction with cert_pem and cert_key_pem it will use a certificate as above. If not will revert to basic auth over HTTPS.
  • kerberos: Will use Kerberos authentication for domain accounts which only works when the client is in the same domain as the server and the required dependencies are installed. Currently a Kerberos ticket needs to be initialized outside of pywinrm using the kinit command.
  • ntlm: Will use NTLM authentication for both domain and local accounts.
  • credssp: Will use CredSSP authentication for both domain and local accounts. Allows double hop authentication. This only works over a HTTPS endpoint and not HTTP.


By default, WinRM will not accept unencrypted communication with a client. There are two ways to enable encrypted communication with pywinrm:

  1. Use an HTTPS endpoint instead of HTTP (Recommended)
  2. Use NTLM, Kerberos, or CredSSP as the transport auth

Using an HTTPS endpoint is recommended, as it will encrypt all the data sent to the server (including all headers), works securely with all auth types, and can properly verify remote host identity (when used with certificates signed by a verifiable certificate authority). You can use this script to easily set up a HTTPS endpoint on WinRM with a self-signed certificate, but the use of a verifiable certificate authority is recommended in production environments.

The second option is to use NTLM, Kerberos, or CredSSP, and set the message_encryption arg to protocol to auto (the default value) or always. This will use the authentication GSS-API Wrap and Unwrap methods to encrypt the message contents sent to the server. This form of encryption is independent of the transport layer, and the strength of the encryption used varies with the underlying authentication type selected (NTLM generally being the weakest and CredSSP the strongest).

To configure message encryption you can use the message_encryption argument when initialising protocol. This option has 3 values that can be set as shown below.

  • auto: Default, Will only use message encryption if it is available for the auth method and HTTPS isn't used.
  • never: Will never use message encryption even when not over HTTPS.
  • always: Will always use message encryption even when running over HTTPS (fails if encryption support is unavailable on the selected auth method).

If you set the value to always and the transport opt doesn't support message encryption (e.g., basic auth or an old version of pykerberos without message encryption support is installed), pywinrm will throw an exception.

If you do not use an HTTPS endpoint or message encryption, a default-configured WinRM server will automatically reject requests from pywinrm. Server settings can be modified allow unencrypted messages and credentials, but this is highly insecure and should only be used for diagnostic purposes. To allow unencrypted communications, run the following on the WinRM server (cmd and powershell versions provided):

# from cmd
winrm set winrm/config/service @{AllowUnencrypted="true"}

# or from powershell
Set-Item -Path "WSMan:\localhost\Service\AllowUnencrypted" -Value $true

Again, this should not be used in production environments, as your credentials and WinRM messages can be trivially recovered.

Enabling WinRM on remote host

Enable WinRM over HTTP and HTTPS with self-signed certificate (includes firewall rules):

# from powershell:
Invoke-Expression ((New-Object System.Net.Webclient).DownloadString(''))

Enable WinRM over HTTP for test usage (includes firewall rules):

winrm quickconfig

Enable WinRM basic authentication. For domain users, it is necessary to use NTLM, Kerberos, or CredSSP authentication (Kerberos and NTLM authentication are enabled by default, CredSSP is not).

# from cmd:
winrm set winrm/config/service/auth @{Basic="true"}

Enable WinRM CredSSP authentication. This allows double hop support so you can authenticate with a network service when running command son the remote host. This command is run in Powershell.

Enable-WSManCredSSP -Role Server -Force
Set-Item -Path "WSMan:\localhost\Service\Auth\CredSSP" -Value $true

Contributors (alphabetically)

  • Alessandro Pilotti
  • Alexey Diyan
  • Chris Church
  • David Cournapeau
  • Gema Gomez
  • Jijo Varghese
  • Jordan Borean
  • Juan J. Martinez
  • Lukas Bednar
  • Manuel Sabban
  • Matt Clark
  • Matt Davis
  • Maxim Kovgan
  • Nir Cohen
  • Patrick Dunnigan
  • Reina Abolofia

Want to help - send a pull request. I will accept good pull requests for sure.

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