Zerologon

The Zerologon exploiter exploits CVE-2020-1472.

Description

An elevation of privilege vulnerability exists when an attacker establishes a vulnerable Netlogon secure channel connection to a domain controller, using the Netlogon Remote Protocol (MS-NRPC).

To download the relevant security update and read more, click here.

A note on safety

This exploiter is not safe for production or other sensitive environments. It is, therefore, not enabled by default.

During successful exploitation, the Zerologon exploiter:

  • will temporarily change the target domain controller’s password.
  • may break the target domain controller’s communication with other systems in the network, affecting functionality.
  • may change the administrator’s password.
  • will attempt to revert all changes.

While the Zerologon exploiter is usually successful in reverting its changes and restoring the original passwords, it sometimes fails. Restoring passwords manually after the Zerologon exploiter has run is nontrivial. For information on restoring the original passwords, see the section on manually restoring your passwords.

To minimize the risk posed by this exploiter, it is recommended that this exploiter be run only against VMs with a recent snapshot and only in testing or staging environments.

Manually restoring your password

This exploiter attempts to restore the original passwords after exploitation. It is usually successful, but it sometimes fails. If this exploiter has changed a password but was unable to restore the original, you can try the following methods to restore the original password.

Restore the VM from a recent snapshot

If the affected system is a virtual machine, the simplest way to restore it to a working state is to revert to a recent snapshot.

Restore the administrator’s password

If you are unable to log in as the administrator, you can follow the instructions here to regain access to the system.

Use Reset-ComputerMachinePassword

If you are able to login as the administrator, you can use the Reset-ComputerMachinePassword powershell command to restore the domain controller’s password.

Try a zerologon password restoration tool

If all other approaches fail, you can try the tools and steps found here.

Notes

  • The Infection Monkey exploiter implementation is based on implementations by @dirkjanm and @risksense.