What Is A Worms?

A computer worm is a software program that is designed to copy itself from one computer to another, without human interaction. Unlike a computer virus, a worm can copy itself automatically.

Worms can replicate in great volume. For example, a worm can send out copies of itself to every contact in your e-mail address book, and then it can send itself to all of the contacts your contact's e-mail address books.

Some worms spread very quickly. They clog networks and can cause long waits for you (and everyone else) to view Web pages on the Internet.

You might have heard of specific computer worms, including the Sasser worm, the Blaster worm, and the Conficker worm.

Use a firewall.
Update your operating system and the software that you use. (Use Windows Update to update all Microsoft products automatically.)
Use antivirus and antispyware software, such as Microsoft Security Essentials, a free download from Microsoft.
Be careful with e-mail attachments and links on Web sites.
Use a standard user account instead of an administrator account.

Protect yourself from Conficker

The Conficker worm is a computer worm that can infect your computer and spread itself to other computers across a network automatically, without human interaction.

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Is my computer infected with the Conficker worm?

Probably not. Microsoft released a security update in October 2008 (MS08-067) to protect against Conficker.

If your computer is up-to-date with the latest security updates and your antivirus software is also up-to-date, you probably don't have the Conficker worm.

If you are still worried about Conficker, follow these steps:

Go to http://update.microsoft.com/microsoftupdate to verify your settings and check for updates.
If you can't access http://update.microsoft.com/microsoftupdate, go to http://safety.live.com and scan your system.
If you can't go to http://safety.live.com, contact support at 1-866-PCSafety or 1-866-727-2338. This phone number is for virus and other security-related support. It is available 24 hours a day for the U.S. and Canada. For support in other countries, visit the Worldwide computer security information page.

What does the Conficker worm do?

To date, security researchers have discovered the following variants of the worm in the wild.

Win32/Conficker.A was reported to Microsoft on November 21, 2008.
Win32/Conficker.B was reported to Microsoft on December 29, 2008.
Win32/Conficker.C was reported to Microsoft on February 20, 2009.
Win32/Conficker.D was reported to Microsoft on March 4, 2009.
Win32/Conficker.E was reported to Microsoft on April 8, 2009.

Win32/Conficker.B might spread through file sharing and via removable drives, such as USB drives (also known as thumb drives). The worm adds a file to the removable drive so that when the drive is used, the AutoPlay dialog box will show one additional option.

The Conficker worm can also disable important services on your computer.

In the screenshot of the Autoplay dialog box below, the option Open folder to view files — Publisher not specified was added by the worm. The highlighted option — Open folder to view files — using Windows Explorer is the option that Windows provides and the option you should use.

If you select the first option, the worm executes and can begin to spread itself to other computers.

The option Open folder to view files — Publisher not specified was added by the worm.

How does the Conficker worm work?

Here’s an illustration of how the Conficker worm works.

Here's a visual explanation of how the Conficker worm works. Back to Top

How do I remove the Conficker worm?

If your computer is infected with the Conficker worm, you may be unable to download certain security products, such as the Microsoft Malicious Software Removal Tool or you may be unable to access certain Web sites, such as Microsoft Update. If you can't access those tools, try using the Windows Live safety scanner.

Where can I find more technical information about the Conficker worm and how can I stay up to date on the Conficker worm?

For additional information, see Centralized Information About the Conficker Worm.
For more technical information about the Conficker worm, see the Microsoft Malware Protection Center Virus Encyclopedia.
Bookmark the Microsoft Malware Protection Center portal and the Microsoft Malware Protection Center blog for updated information.
For symptoms and detailed information about how to remove the Conficker worm, see Help and Support: Virus alert about the Conficker Worm.
To continue to get updated information on security, sign up for the Microsoft Security for Home Computer Users newsletter.

For more information, see How to prevent computer worms and How to remove computer worms.