No remote desktop logon possible from outside the Active Directory forest

Assume the following scenario:

  • You want to establish a remote desktop connection.
  • The client computer from which the connection is made is not a member of the same Active Directory forest as the target computer.
  • The connection fails with the following error message:
A user account restriction (for example, a time-of-day restriction) is preventing you from logging on. For assistance, contact your system administrator or technical support.
Continue reading „Keine Anmeldung per Remotedesktop von außerhalb der Active Directory Gesamtstruktur möglich“

Automatic renewal of manually requested certificates without intervention of a certificate manager

Assuming a use case is implemented for certificates where users specify the identity contained in the certificate in the certificate request, and this requires manual intervention by the certificate managers, the question arises as to how to proceed when the certificates expire or the certificate template is moved to another certification authority in order to minimize tickets at the help desk and thus the resulting work for the certificate managers.

Continue reading „Automatische Erneuerung manuell beantragter Zertifikate ohne Eingriff eines Zertifikatmanagers“

From Zero to Enterprise Administrator through Network Device Enrollment Service (NDES) - and What to Do About It

In the following, I would like to present a highly dangerous PKI configuration, perhaps not necessarily known to the general public, which can probably be encountered quite frequently in this way in corporate networks.

I show how, by exploiting various unfortunate circumstances in the Windows PKI, it is possible to elevate privileges from mere network access to complete Active Directory takeover.

The initial point of attack in this example is the Network Device Enrollment Service (NDES).

Continue reading „Von Null auf Enterprise Administrator durch den Registrierungsdienst für Netzwerkgeräte (NDES) – und was dagegen getan werden kann“