Repair: The System Detected a Possible Attempt to Compromise Security

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This specific error message can occur in several different scenarios on users’ computers. This is a Windows related error message. A scenario occurs when users attempt to enter a password to access their account, but Windows refuses to accept it.

Kerberos uses the UDP protocol to exchange tickets according to the RFC standard. UDP is an elaborate protocol, and things like VPNs or busy networks cause strange events (like not being able to authenticate). Kerberos cannot tolerate packages being out of service, which can happen due to MTU size, latency, etc. Kerberos cannot tolerate packages being out of order.

Microsoft allows you to break the standard and force Windows to use TCP for Kerberos authentication via registry editing.

Error message:

The system detected a possible attempt to compromise security. Please ensure that you can contact the server that authenticated you.

What happens in the background when a user in a forest needs to access a resource in a remote trust domain is as follows:

  • The customer contacts a KDC in his own field.
  • The KDC provides the customer with a sponsorship ticket for the remote domain.
  • The customer sends the sponsorship ticket to a KDC in the trusted forest.
  • The trusted KDC recognizes the validity and authenticity of the recommendation ticket.
  • The user is assigned a service ticket for the service in the remote domain.

KB3167679 – MS16-101 Workaround

  • If successful password changes before fail after the installation of MS16-101, it is likely that the password changes were previously based on NTLM’s failover because Kerberos failed. To change passwords using Kerberos protocols, do the following:
  • Configure open communication on TCP port 464 between the clients on which MS16-101 is installed and the domain controller waiting for the password reset.

Read-only domain controllers (RODCs) can reset self-service passwords if the user is authorized by the RODCs’ password replication policy. Users who are not authorized by the RODC password policy need a network connection to a Read/Write Domain Controller (RWDC) in the user account domain.

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Note To verify that TCP port 464 is open, do the following:
Create an equivalent display filter for your network monitor analyzer. For example:

ipv4.address== <ip address of client> && tcp.port==464

Use IPv4 in your network

IPv6 poses many problems and has become the cause of many network connectivity problems. You can try to solve the problem described in this article by simply switching your network to IPv4 instead of IPv6.

  1. Use the Windows + R keyboard shortcut, which immediately opens the Run dialog box, where you must type ncpa.cpl in the bar and click OK to open the Internet Connection Settings item in the Control Panel.
  2. You can do the same by opening the Control Panel manually. Change the display by clicking on Define Category at the top right of the window and clicking on Network and Internet at the top. Click the Sharing and Network Center button to open it. Try to find and click on the Change Adapter Settings button in the left menu.
  3. When the Internet Connection window opens, double-click on your active network adapter.
  4. Then click on Properties and locate Internet Protocol version 6 in the list. Uncheck the box next to this entry and click OK. Restart your computer to confirm the changes and verify that the problem persists.

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