Modify Authentication Process: Network Provider DLL

Adversaries may register malicious network provider dynamic link libraries (DLLs) to capture cleartext user credentials during the authentication process. Network provider DLLs allow Windows to interface with specific network protocols and can also support add-on credential management functions.[1] During the logon process, Winlogon (the interactive logon module) sends credentials to the local mpnotify.exe process via RPC. The mpnotify.exe process then shares the credentials in cleartext with registered credential managers when notifying that a logon event is happening.[2][3][4]

Adversaries can configure a malicious network provider DLL to receive credentials from mpnotify.exe.[5] Once installed as a credential manager (via the Registry), a malicious DLL can receive and save credentials each time a user logs onto a Windows workstation or domain via the NPLogonNotify() function.[4]

Adversaries may target planting malicious network provider DLLs on systems known to have increased logon activity and/or administrator logon activity, such as servers and domain controllers.[2]

ID: T1556.008
Sub-technique of:  T1556
Platforms: Windows
Contributors: CrowdStrike Falcon OverWatch; Jai Minton
Version: 1.0
Created: 30 March 2023
Last Modified: 04 May 2023


ID Mitigation Description
M1047 Audit

Periodically review for new and unknown network provider DLLs within the Registry (HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\<NetworkProviderName>\NetworkProvider\ProviderPath).

Ensure only valid network provider DLLs are registered. The name of these can be found in the Registry key at HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\NetworkProvider\Order, and have corresponding service subkey pointing to a DLL at HKEY_LOCAL_MACHINE\SYSTEM\CurrentC ontrolSet\Services\<NetworkProviderName>\NetworkProvider.

M1028 Operating System Configuration

Starting in Windows 11 22H2, the EnableMPRNotifications policy can be disabled through Group Policy or through a configuration service provider to prevent Winlogon from sending credentials to network providers.[6]

M1024 Restrict Registry Permissions

Restrict Registry permissions to disallow the modification of sensitive Registry keys such as HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\NetworkProvider\Order.


ID Data Source Data Component Detects
DS0022 File File Creation

Monitor for newly created files that may be used to register malicious network provider dynamic link libraries (DLLs).

DS0009 Process OS API Execution

Monitor for abnormal API calls to NPLogonNotify().[4]

DS0024 Windows Registry Windows Registry Key Creation

Monitor for the addition of network provider Registry keys (e.g., HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\<NetworkProviderName>\NetworkProvider).

Windows Registry Key Modification

Monitor for changes to Registry entries for network providers (e.g., HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\NetworkProvider\Order) and correlate then investigate the DLL files these values reference.