- 16 July 2001
- 13 February 2007
This worm spreads by using Microsoft Outlook. It adds a value to the registry and drops a VBS file that, if run, drops a .bat file that deletes all files in the C:\, C:\Windows, C:\Documenti, and C:\Programmi folders.
Antivirus Protection Dates
- Initial Rapid Release version 16 July 2001
- Latest Rapid Release version 28 September 2010 revision 054
- Initial Daily Certified version 16 July 2001
- Latest Daily Certified version 28 September 2010 revision 036
- Initial Weekly Certified release date pending
Click here for a more detailed description of Rapid Release and Daily Certified virus definitions.
This worm is a Visual Basic Script (VBS) worm that uses Microsoft Outlook to spread. It sends itself to all addresses in the Microsoft Outlook address book. It arrives as:
Message: Check the attachement!
The worm adds the value
to the registry key
This allows it to run as a service the next time that Windows starts. The Counsrpt.vbs file overwrites the Autoexec.bat file with a file that contains commands to delete all files in the following folders:
Due to the naming of the latter two folders, the worm will only delete documents and programs on a specific non-English version of Windows. It also creates two folders on the hard drive, and makes them the A and D drives. This is to prevent you from reinstalling deleted system files from the floppy disk drive or the CD-ROM drive.
NOTE: You will only be prevented from reinstalling the deleted files when the virus is running.
It also changes your desktop wallpaper to an .html file containing the word "decrypt!" and the following string of characters:
Symantec Security Response encourages all users and administrators to adhere to the following basic security "best practices":
- Use a firewall to block all incoming connections from the Internet to services that should not be publicly available. By default, you should deny all incoming connections and only allow services you explicitly want to offer to the outside world.
- 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.
- Ensure that programs and users of the computer use the lowest level of privileges necessary to complete a task. When prompted for a root or UAC password, ensure that the program asking for administration-level access is a legitimate application.
- Disable AutoPlay to prevent the automatic launching of executable files on network and removable drives, and disconnect the drives when not required. If write access is not required, enable read-only mode if the option is available.
- Turn off file sharing if not needed. If file sharing is required, use ACLs and password protection to limit access. Disable anonymous access to shared folders. Grant access only to user accounts with strong passwords to folders that must be shared.
- Turn off and remove unnecessary services. By default, many operating systems install auxiliary services that are not critical. These services are avenues of attack. If they are removed, threats have less avenues of attack.
- If a 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.
- Configure your email server to block or remove email that contains file attachments that are commonly used to spread threats, such as .vbs, .bat, .exe, .pif and .scr files.
- Isolate compromised computers quickly to prevent threats from spreading further. 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.
- If Bluetooth is not required for mobile devices, it should be turned off. If you require its use, ensure that the device's visibility is set to "Hidden" so that it cannot be scanned by other Bluetooth devices. If device pairing must be used, ensure that all devices are set to "Unauthorized", requiring authorization for each connection request. Do not accept applications that are unsigned or sent from unknown sources.
- For further information on the terms used in this document, please refer to the Security Response glossary.
To remove this worm, delete the files detected as VBS.Count.A.int, look for and delete files in the list that follows, and undo the changes that the worm made to the registry. In some cases, you must reinstall Windows.
To remove most of the worm files:
This will remove many--but not necessarily all--of the files that were dropped:
- Run LiveUpdate to make sure that you have the most recent virus definitions.
- Start Norton AntiVirus (NAV), and then run a full system scan, making sure that NAV is set to scan all files.
- Delete any files detected as VBS.Count.A.int. (We suggest that you write down the file names of the files that you delete; this will make the removal process that is described in the next section somewhat easier.)
To delete files with Windows Explorer:
Using Windows Explorer, delete any of the files in the following list that were not deleted during the NAV scan.
To edit the registry:
CAUTION : We strongly recommend that you back up the system registry before making any changes. Incorrect changes to the registry could result in permanent data loss or corrupted files. Please make sure you modify only the keys specified. Please see the document How to back up the Windows registry before proceeding.
- Click Start, and then click Run. The Run dialog box appears.
- Type regedit and then click OK. The Registry Editor opens.
- Navigate to the following key:
in the right pane, delete the value
- Click the Registry menu, and then click Exit to save the changes.
Reinstall Windows if necessary
See your Microsoft Windows installation instructions for additional information.