Windows Defender RRS feed

  • Question

  • Windows Defender, previously known as Microsoft AntiSpyware, is a software product from Microsoft designed to prevent, remove and quarantine spyware in Microsoft Windows. It is part of Windows Vista and available as a free download for previous supported versions of Windows.



    Windows Defender is based on GIANT AntiSpyware, which was originally developed by GIANT Company Software, Inc. The company's acquisition was announced by Microsoft on December 16, 2004. While the original GIANT AntiSpyware supported older versions of Windows, support for the Windows 9x line of operating systems was dropped. However, Sunbelt Software, which was originally GIANT's partner, sells a product based in the same technology called Counterspy which still has support for older Microsoft operating systems.


    At the 2005 RSA Security conference, Chief Software Architect and co-founder of Microsoft, Bill Gates, announced that Windows Defender (which was actually known as Microsoft AntiSpyware prior to November 4, 2005) will be made available free of charge to all validly licensed Windows 2000, Windows XP, and Windows Server 2003 users to help secure Windows users world-wide against the increasing threat of malware. Microsoft's upcoming Windows Vista operating system will also have Defender included as an integrated part of the operating system, and will be enabled by default.


    Windows Defender not only features scanning of the system similar to other free products on the market, but also includes a number of Real-Time Security Agents that monitor several common areas of Windows for changes which may be caused by spyware. It also includes the ability to easily remove ActiveX applications that are installed. Also integrated is support for Microsoft's SpyNet network, that allows users to report to Microsoft what they consider to be spyware, and what applications and device drivers they allow to be installed on their system.



    Windows AntiSpyware Beta 1 (Version 1.0.701)

    Beta 1

    The first release of Microsoft AntiSpyware was released in beta form on January 6, 2005 and was basically a repackaged GIANT AntiSpyware. It was then a free product (though only for genuine installations of Windows) and the word GIANT disappeared from the product. Few new features were added over the GIANT product; it was mainly a temporary re-branding release until it could be rewritten and rebranded. More builds were released as 2005 progressed, with the last Beta 1 refresh released on November 21, 2005.


    Friday, March 23, 2007 8:47 AM


  • Beta 2

    Windows Defender (Beta 2) was released on February 13, 2006. It featured the program's new name and a significant redesign, resulting in huge improvements. The core engine was rewritten in C++, unlike the original GIANT-developed one, which was written in Visual Basic. This improved the performance of the application. Also, the program now works as a Windows service, unlike the earlier release, which enables the application to protect the computer even when a user is not logged on. Because of this, the Windows Defender application is technically an interface to the service, which is also called by the same name. In addition, the application now protects more points-of-entry than the original application, while providing a more streamlined and intuitive interface. Beta 2 also requires Windows Genuine Advantage validation. However, Windows Defender (Beta 2) did not contain some of the tools found in Microsoft AntiSpyware (Beta 1). This consists of removed functionality of the System Explorer tool found in MSAS (Beta 1) and the Tracks Eraser tool, which allows the user to easily delete many different types of temporary files found in Windows, including cookies, temporary internet files, and Windows Media Player playing history. Microsoft recently released a German and Japanese version of Windows Defender (Beta 2).



    General Release

    On October 24, 2006, Microsoft announced the general release of Windows Defender. It supports Windows XP and Windows Server 2003; however, unlike the betas, it does not support Windows 2000. Support for Windows 2000 was cut because at the time of RTM release, Windows 2000 was considered not to be "a popular consumer operating system" and had reached the end of its mainstream support period. Despite this, users have reported that the InstallShield package bundled with this release of Windows Defender contains an artificial rule that stops Windows Defender from installing on a Windows 2000 computer. If this condition is removed, Windows Defender will install and run fine on Windows 2000 systems.


    Advanced features


    Windows Defender is shown here blocking Hotbar, a known adware bundler.

    Real-time protection

    In the Windows Defender Options you can configure the Real-time Protection options:


    Auto Start - Monitors lists of programs that are allowed to automatically run when you start your computer

    System Configuration (settings) - Monitors security-related settings in Windows

    Internet Explorer Add-ons - Monitors programs that automatically run when you start Internet Explorer

    Internet Explorer Configurations (settings) - Monitors browser security settings

    Internet Explorer Downloads - Monitors files and programs that are designed to work with Internet Explorer

    Services and Drivers - Monitors services and drivers as they interact with Windows and your programs

    Application Execution - Monitors when programs start and any operations they perform while running

    Application Registration - Monitors tools and files in the operating system where programs can register to run at any time

    Windows Add-ons - Monitors add-on programs (also known as software utilities) for Windows


    Internet Explorer integration

    There is integration with Internet Explorer which enables files to be scanned when they are downloaded to help ensure that one does not accidentally download malicious software. This implementation is similar to the real-time scanners of many Anti-Virus products on the market.



    Software Explorer

    The Advanced Tools section allows users to discover potential vulnerabilities for themselves with a series of Software Explorers. They provide views of startup programs, currently running software, and Windows sockets providers (Winsock LSPs). In each Explorer, every element is rated as either "Known", "Unknown" or "Potentially Unwanted". The first and last categories carry a link to learn more about the particular item, and the second category invites you to submit the program to SpyNet for analysis by experts.



    Windows Vista specific functionality

    Windows Defender in Windows Vista automatically blocks all startup items that require administrator privileges to run (this is considered a bad behaviour for a startup item). There is no known easy way to automatically unblock these items, the only suggestion given is to "contact the software vendor for an updated version" which is Vista compatible (does not require administrator privileges to run). This automatic blocking is related to the UAC (User Account Control) functionality in Windows Vista, and requires the user to manually run each of these startup items each time they log in. If there is no updated version of the startup item, the only currently known way to circumvent this behavior is to disable UAC altogether (since this is also a UAC related functionality, disabling Windows Defender while not disabling UAC will not solve the issue).

    Friday, March 23, 2007 8:47 AM