Adversaries may modify or add LSASS drivers to obtain persistence on compromised systems. The Windows security subsystem is a set of components that manage and enforce the security policy for a computer or domain. The Local Security Authority (LSA) is the main component responsible for local security policy and user authentication. The LSA includes multiple dynamic link libraries (DLLs) associated with various other security functions, all of which run in the context of the LSA Subsystem Service (LSASS) lsass.exe process.[1]
Adversaries may target LSASS drivers to obtain persistence. By either replacing or adding illegitimate drivers (e.g., Hijack Execution Flow), an adversary can use LSA operations to continuously execute malicious payloads.
| ID | Name | Description |
|---|---|---|
| S0208 | Pasam |
Pasam establishes by infecting the Security Accounts Manager (SAM) DLL to load a malicious DLL dropped to disk.[2] |
| S0176 | Wingbird |
Wingbird drops a malicious file (sspisrv.dll) alongside a copy of lsass.exe, which is used to register a service that loads sspisrv.dll as a driver. The payload of the malicious driver (located in its entry-point function) is executed when loaded by lsass.exe before the spoofed service becomes unstable and crashes.[3][4] |
| ID | Mitigation | Description |
|---|---|---|
| M1043 | Credential Access Protection |
On Windows 10 and Server 2016, enable Windows Defender Credential Guard [5] to run lsass.exe in an isolated virtualized environment without any device drivers. [6] |
| M1025 | Privileged Process Integrity |
On Windows 8.1 and Server 2012 R2, enable LSA Protection by setting the Registry key |
| M1044 | Restrict Library Loading |
Ensure safe DLL search mode is enabled |
| ID | Data Source | Data Component | Detects |
|---|---|---|---|
| DS0027 | Driver | Driver Load |
With LSA Protection enabled, monitor the event logs (Events 3033 and 3063) for failed attempts to load LSA plug-ins and drivers. [7] Utilize the Sysinternals Autoruns/Autorunsc utility [9] to examine loaded drivers associated with the LSA. |
| DS0022 | File | File Creation |
Monitor newly constructed files that may modify or add LSASS drivers to obtain persistence on compromised systems. |
| File Modification |
Monitor for changes made to files that may modify or add LSASS drivers to obtain persistence on compromised systems. |
||
| DS0011 | Module | Module Load |
Also monitor DLL load operations in lsass.exe. [8] |