Learn how Forefront endpoint security products use definition files (VDMs) to identify malware and how to obtain updates from Microsoft Update, Windows Server Update Services, or manual download. The MpAsBase.vdm file contains the antispyware base definition module and is updated monthly.

Full update. A full update includes a new anti-malware engine and copies of the base delta definition files for both antispyware and antivirus functionality. These files include the following: Mpasbase.vdm. Mpasdlta.vdm. Mpavbase.vdm. Mpavdlta.vdm.

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section. Describes the symptoms of a data corruption problem that may occur on computers that have Forefront Client Security installed. Provides workarounds for this problem.

The updates improve the Windows Defender baseline engines and signatures in the Windows 8 and Windows 8.1 disk images that are created by OEMs. For the best protection, Windows Defender engines and signatures should be kept up-to-date.

This article describes the Microsoft Forefront Client Security (FCS) anti-malware client issues that are fixed in this hotfix package for Forefront Client Security.

This update changes MpFilter.sys to resolve this issue and to replace the update that is described in the following article: 2459065 Real-time protection fails on Windows 2000 after you apply the Forefront Client Security October 2010 update.

Microsoft 反恶意软件代理使用病毒定义模块 (Vdm) 来存储有关恶意软件或潜在不需要的软件的检测信息。反恶意软件代理在其常规操作过程中使用下面的五个文件 MpAvBase.vdm文件中包含防病毒的基本定义模块。

Microsoft has identified an issue in the Forefront Client Security agent on Windows 2000 which prevents the kernel-mode mini-filter driver, mpfilter.sys, from properly loading. This issue is specific to agents running on Windows 2000 and the Client Security October update and does not occur on other operating systems.

Symptom 1 occurs because of a permission issue that is specific to Windows 2000. In Windows 2000, a non-administrator user is denied access to the RegisterGPNotification function. This function is used to monitor policy changes.

O arquivo MpAvBase.vdm contém o módulo antivírus definição básica. Esse arquivo é normalmente atualizado apenas uma vez por mês pela Microsoft e contém as informações de vírus base que são usadas para criar as definições de delta.