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. 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.
Adversaries can configure a malicious network provider DLL to receive credentials from
mpnotify.exe. 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
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.
Periodically review for new and unknown network provider DLLs within the Registry (
Ensure only valid network provider DLLs are registered. The name of these can be found in the Registry key at
|M1028||Operating System Configuration||
Starting in Windows 11 22H2, the
|M1024||Restrict Registry Permissions||
Restrict Registry permissions to disallow the modification of sensitive Registry keys such as
|ID||Data Source||Data Component||Detects|
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
|DS0024||Windows Registry||Windows Registry Key Creation||
Monitor for the addition of network provider Registry keys (e.g.,
|Windows Registry Key Modification||
Monitor for changes to Registry entries for network providers (e.g.,