Security Support Provider
Windows Security Support Provider (SSP) DLLs are loaded into the Local Security Authority (LSA) process at system start. Once loaded into the LSA, SSP DLLs have access to encrypted and plaintext passwords that are stored in Windows, such as any logged-on user's Domain password or smart card PINs. The SSP configuration is stored in two Registry keys:
HKLM\SYSTEM\CurrentControlSet\Control\Lsa\Security Packages and
HKLM\SYSTEM\CurrentControlSet\Control\Lsa\OSConfig\Security Packages. An adversary may modify these Registry keys to add new SSPs, which will be loaded the next time the system boots, or when the AddSecurityPackage Windows API function is called. 
Windows 8.1, Windows Server 2012 R2, and later versions may make LSA run as a Protected Process Light (PPL) by setting the Registry key
HKLM\SYSTEM\CurrentControlSet\Control\Lsa\RunAsPPL, which requires all SSP DLLs to be signed by Microsoft.  
Monitor the Registry for changes to the SSP Registry keys. Monitor the LSA process for DLL loads. Windows 8.1 and Windows Server 2012 R2 may generate events when unsigned SSP DLLs try to load into the LSA by setting the Registry key
HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\LSASS.exe with AuditLevel = 8.