Linux and macOS implementation of the Local Administrator Password Solution (LAPS) from Microsoft. The client is also executable under Windows and provides additional features (e.g. display additional LDAP values, directly start remote connections and it can be called with laps:// protocol scheme parameter to directly start search).
Microsoft introducted the new "Native LAPS" in 2023. In contrast to Legacy LAPS, the new version uses different LDAP attributes and has the option to store the password encrypted in the LDAP directory. LAPS4LINUX supports both versions out-of-the-box. The client will search for a password in the following order: Native LAPS encrypted, Native LAPS unencrypted, Legacy LAPS (unencrypted).
The runner can operate in Legacy or Native mode by switching the setting native-laps to true or false. In Native mode, the runner stores the password and username as JSON string in the LDAP attribute, as defined by Microsoft. In addition to that, when in Native mode, you can set security-descriptor to a valid SID in your domain and the runner will encrypt the password for this user/group. Please note: only SID security descriptors are supported (e.g. S-1-5-21-2185496602-3367037166-1388177638-1103), do not use group names (DOMAIN\groupname). If you enable encryption, you should also change ldap-attribute-password to msLAPS-EncryptedPassword to store the encrypted password in the designated LDAP attribute for compatibility with other Tools. Please have a look at the runner section below for more information.
$ ./laps-cli.py notebook01 --set-expiry "2021-04-28 01:01:01"
LAPS4LINUX CLI v1.0.0
https://github.com/schorschii/laps4linux
🔑 Password for »ldapuser«:
Connection: ldapserver01: [email protected]
Found: CN=NOTEBOOK01,OU=NOTEBOOKS,DC=example,DC=com
Password: abc123
Expiration: 132641316610000000 (2021-04-29 01:01:01)
New Expiration: 132640452610000000 (2021-04-28 01:01:01)
Expiration Date Changed Successfully.
$ ./laps-cli.py "*"
LAPS4LINUX CLI v1.0.0
https://github.com/schorschii/laps4linux
🔑 Password for »ldapuser«:
Connection: ldapserver01: [email protected]
NOTEBOOK01$ : abc123
NOTEBOOK02$ : 123abc
...
By default, the clients will try to auto-discover your domain and LDAP servers via DNS. If this does not succeed, the client will ask you for this values and write it to the config file ~/.config/laps-client/settings.json.
You can create a preset config file /etc/laps-client.json which will be loaded if ~/.config/laps-client/settings.json does not exist. With this, you can distribute default settings (all relevant LDAP attributes, SSL on etc.) for new users.
Configuration Values
server: Array of domain controllers with items like{"address": "dc1.example.com", "port": 389, "ssl": false}. Leave empty for DNS auto discovery.domain: Your domain name (e.g.example.com). Leave empty for DNS auto discovery.use-starttls: Boolean which indicates wheter to use StartTLS on unencrypted LDAP connections (requires valid server certificate).username: The username for LDAP simple binds.use-kerberos: Boolean which indicates wheter to use Kerberos for LDAP bind before falling back to simple bind.ldap-attributes: A dict of LDAP attributes to display. Dict key is the display name and the corresponding value is the LDAP attribute name. The dict value can also be a list of strings. Then, the first non-empty LDAP attribute will be displayed.ldap-attribute-password: The LDAP attribute name which contains the admin password. The client will try to decrypt this value (in case of Native LAPS) and use it for Remmina connections. Can also be a list of strings.ldap-attribute-password-expiry: The LDAP attribute name which contains the admin password expiration date. The client will write the updated expiration date into this attribute. Can also be a list of strings.ldap-attribute-password-history: The LDAP attribute name which contains the admin password history. The client will try to decrypt this value (in case of Native LAPS) and use it to display the password history. Can also be a list of strings.connect-username: The username which will be used for Remmina connections. May be modified by the client during the runtime since Native LAPS also stores username information.
If you want to view the DSRM password, simply put msLAPS-EncryptedDSRMPassword and msLAPS-EncryptedDSRMPasswordHistory into the ldap-attributes and ldap-attribute-password|ldap-attribute-password-history configuration.
The client (both GUI and CLI) supports Kerberos authentication which means you can use the client without entering a password if you are logged in with a domain account and have a valid Kerberos ticket (for this, an SSL connection is required). If not, ldap3's "simple" authentication is used as fallback and the client will ask you for username and password. The Kerberos authentication attempt can be disabled by setting use-kerberos to false in the config file.
If you did not automatically received a Kerberos ticket on login, you can manually aquire a ticket via kinit <username>@<DOMAIN.TLD>.
By default, LAPS4LINUX (client and runner) will connect via LDAP on port 389 to your Active Directory and upgrade the connection via STARTTLS to an encrypted one. This means that your server needs a valid certificate and STARTTLS enabled. This behavior can be disabled by modifying the use-starttls in the config file, but it is strongly discouraged to disable it since sensitive data is transferred.
Alternatively, you can use LDAPS by editing the config file (~/.config/laps-client/settings.json): modify the server entry and set ssl to true and port to 636 (see example below). You can also configure multiple static LDAP servers in the config file.
If you are managing multiple domains, you probably want to search for a computer in all domains. Please use the global catalog for this by setting the option gc-port in the configuration file of all servers, e.g. to 3268 (LDAP) or 3269 (LDAPS).
Example
{
"server": [
{
"address": "dc.example.com",
"port": 636,
"gc-port": 3269,
"ssl": true
},
.....
],
.....
}
Since the global catalog is read only, LAPS4LINUX will switch to "normal" LDAP(S) port when you want to change the password expiry date. That's why, the port option is still required even if a gc-port is given!
LAPS4LINUX allows you to query additional attributes besides the admin password which might be of interest for you. For that, just edit the config file ~/.config/laps-client/settings.json and enter the additional LDAP attributes you'd like to query into the settings array "ldap-attributes".
The setting ldap-attribute-password-expiry defines in which LDAP attribute the date will be written when selecting a new expiration date. If you like, you can hide the "Set Expiration" button by entering an empty string for this setting.
With the setting ldap-attribute-password you define which LDAP attribute is considered as the admin password (for usage with the Remmina connect feature).
On Linux, the GUI allows you to directly open RDP or SSH connections via Remmina from the menu. Please make sure you have installed the latest Remmina with RDP and SSH extensions. You can change the username which is used for the connection in the client config ("connect-username": "administrator").
Flatpak Remmina
If you use Remmina installed via Flatpak, you need to create the following wrapper script which calls the Flatpak version of remmina. Do not forget to make it executable.
*** /usr/local/bin/remmina ***
#!/bin/bash
flatpak run org.remmina.Remmina $@
The clients (GUI and CLI) are also executable under Windows and macOS. It's ported to Windows because of the additional features that the original LAPS GUI did not have (query custom attributes, OCO integration).
The GUI supports the protocol scheme laps://, which means you can call the GUI like laps-gui.py laps://HOSTNAME to automatically search HOSTNAME after startup. This feature is mainly intended to use with the OCO server web frontend ("COMPUTER_COMMANDS").
Linux
On Linux, you need to create file /usr/share/applications/LAPS4LINUX-protocol-handler.desktop with the following content and execute update-desktop-database.
[Desktop Entry]
Type=Application
Name=LAPS4LINUX Protocol Handler
Exec=/usr/bin/laps-gui %u
StartupNotify=false
MimeType=x-scheme-handler/laps;
NoDisplay=true
macOS
On macOS, the protocol handler is registered using the Info.plist file (setting "CFBundleURLTypes") in the .app directory. Please use laps-gui.macos.spec with pyinstaller to automatically create an .app directory which registers itself for the laps:// protocol on first launch.
Windows
On Windows, you need to set the following registry values:
Windows Registry Editor Version 5.00
[HKEY_CLASSES_ROOT\laps]
@="URL:LAPS"
"URL Protocol"=""
[HKEY_CLASSES_ROOT\laps\shell]
[HKEY_CLASSES_ROOT\laps\shell\open]
[HKEY_CLASSES_ROOT\laps\shell\open\command]
@="\"C:\\Program Files\\LAPS4WINDOWS\\laps-gui.exe\" %1"
The runner is responsible for automatically changing the admin password of a Linux client and updating it in the LDAP directory. This assumes that Kerberos (krb5-user) is installed and that the machine is already joined to your domain using Samba's net ads join, PBIS' domainjoin-cli join or the adcli join command (recommended). realm join is also supported as it internally also uses adcli resp. Samba.
A detailed domain join guide is available on my website (attention: only in German).
The runner should be called periodically via cron. It decides by the expiration time stored in the LDAP directory when the password should be changed.
*** /etc/cron.hourly/laps-runner ***
SHELL=/bin/sh
PATH=/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin
/usr/sbin/laps-runner --config /etc/laps-runner.json
Please make sure that usermod (for changing the password in the local database) is in you crontab $PATH (this is the default in Debian and Ubuntu based systems, but may not in other distros).
Please configure the runner by editing the configuration file /etc/laps-runner.json.
Configuration Values
server: Array of domain controllers with items like{"address": "dc1.example.com", "port": 389, "ssl": false}. Leave empty for DNS auto discovery.domain: Your domain name (e.g.example.com). Leave empty for DNS auto discovery.use-starttls: Boolean which indicates wheter to use StartTLS on unencrypted LDAP connections (requires valid server certificate).client-keytab-file: The Kerberos keytab file with the machine secret.cred-cache-file: File where to store the kerberos ticket for the LDAP connection.native-laps:trueto store the password as JSON string in the LDAP attribute, as specified by Microsoft (Native LAPS).falseto store it as plaintext (Legacy LAPS).security-descriptor: The security descriptor (SID) for pasword encryption (Native LAPS only). Leave empty (set tonull) to disable encryption. Important: if you enable encryption, you should also changeldap-attribute-passwordtomsLAPS-EncryptedPassword!history-size: The amount of password entries to keep in history. If not set or0, no password history will be written.ldap-attribute-password: The LDAP attribute name where to store the generated password. Must be a string, not a list.ldap-attribute-password-history: The LDAP attribute where to store the password history. Must be a multi-value text field. If empty, no password history will be written.ldap-attribute-password-expiry: The LDAP attribute where to store the password expiration date. Must be a string, not a list.hostname: The hostname used for Kerberos ticket creation. Leave empty to use the system's hostname.password-change-user: The Linux user whose password should be rotated.password-days-valid: The amount of days how long a password should be valid.password-length: Determines how long a generated password should be.password-alphabet: Determines the chars to use for password generation.
Important:
- If
native-lapsisfalse, you should setldap-attribute-passwordtoms-Mcs-AdmPwdandldap-attribute-password-expirytoms-Mcs-AdmPwdExpirationTime. - If If
native-lapsistrueandsecurity-descriptornot set ornull, you should setldap-attribute-passwordtomsLAPS-Passwordandldap-attribute-password-expirytomsLAPS-PasswordExpirationTime. - If If
native-lapsistrueandsecurity-descriptoris set to a valid SID in your domain, you should setldap-attribute-passwordtomsLAPS-EncryptedPasswordandldap-attribute-password-expirytomsLAPS-PasswordExpirationTime. - While it is technically possible to save the password history unencrypted, Microsoft did not designated this. By default, in Active Directory, the only password history attribute is
msLAPS-EncryptedPasswordHistory. Therefore, you should only configure the runner to store a password history when using password encryption too.
You can call the runner with the -f parameter to force updating the password directly after installation. You should do this to check if the runner is working properly.
Computer objects in the Microsoft Active Directory can not be longer than 15 characters. If you join a computer with a longer hostname, it will be registered with a different "short name". You have to enter this short name in the config file (setting hostname) in order to make the Kerberos authentication work. You can find out the short name by inspecting your keytab: sudo klist -k /etc/krb5.keytab.
Set the hostname option to null (default) to use the system's normal host name.
If the script throws an error like kinit -k -c /tmp/laps.temp SERVER$ returned non-zero exit code 1, please check what happens when you execute the following commands manually on the command line.
sudo kinit -k -c /tmp/laps.temp COMPUTERNAME$
sudo klist -c /tmp/laps.temp
Please replace COMPUTERNAME with your hostname, but do not forget the trailing dollar sign.
If you like LAPS4LINUX please consider making a donation using the sponsor button on GitHub to support further development.
You can hire me for commercial support or adjustments for this project. Please contact me if you are interested.