For remove W32.Dutan.A virus,please clean/delete all W32.Dutan.A infected files and Delete/Modify any values W32.Dutan.A added to the registry as following:
When the worm executes, it copies itself to the following locations:
%System%\winxpsp2.dll
%System%\csrsss.exe
%System%\svchosts.exe
The worm then attempts to spread by copying itself to all network and removable drives as the following file: %DriveLetter%\svchosts.exe
It also creates the following file so that it executes whenever the drive is accessed: %DriveLetter%\autorun.inf
Next, the worm creates the following registry entry so that it executes whenever Windows starts: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run\"Microsoft OfficeTool" = "svchosts.exe"
It may also create the following registry entries:
Next, the worm searches for .xls files on all available drives.
It then prepends 2 kilobytes (KB) of random bytes to any files that it finds.
This prevents Microsoft Excel from recognising these files properly. However, the data in the files is still intact.
Recommendations
Symantec Security Response encourages all users and administrators to adhere to the following basic security "best practices":
Turn off and remove unneeded services. By default, many operating systems install auxiliary services that are not critical, such as an FTP server, telnet, and a Web server. These services are avenues of attack. If they are removed, blended threats have less avenues of attack and you have fewer services to maintain through patch updates.
If a blended threat exploits one or more network services, disable, or block access to, those services until a patch is applied.
Always keep your patch levels up-to-date, especially on computers that host public services and are accessible through the firewall, such as HTTP, FTP, mail, and DNS services (for example, all Windows-based computers should have the current Service Pack installed.). Additionally, please apply any security updates that are mentioned in this writeup, in trusted Security Bulletins, or on vendor Web sites.
Enforce a password policy. Complex passwords make it difficult to crack password files on compromised computers. This helps to prevent or limit damage when a computer is compromised.
Configure your email server to block or remove email that contains file attachments that are commonly used to spread viruses, such as .vbs, .bat, .exe, .pif and .scr files.
Isolate infected computers quickly to prevent further compromising your organization. Perform a forensic analysis and restore the computers using trusted media.
Train employees not to open attachments unless they are expecting them. Also, do not execute software that is downloaded from the Internet unless it has been scanned for viruses. Simply visiting a compromised Web site can cause infection if certain browser vulnerabilities are not patched.
For successful remove W32.Dutan.A virus,you may also need do as following:
1. Temporarily Disable System Restore .
2. Update the virus definitions. Reboot computer in SafeMode;
