T1556.008 — Modify Authentication Process: Network Provider DLL
Sub-technique of T1556 Modify Authentication Process
Description
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 `NPLogonNotify()` function.
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.
Detected by EasySIEM
This project's own SigmaHQ-derived detection pipeline tags every compiled rule with the ATT&CK technique(s) it maps to -- if a rule in your install covers this technique, it shows up automatically on your own Grafana Alerts dashboard's "Top ATT&CK Techniques" panel, no lookup needed. This page exists so a click from there always lands here on easysiem.com, not on attack.mitre.org.