Threat Explorer

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15 June 2001
13 February 2007
Also Known As:
VBS.Haptime.A@mm, VBS/Haptime.A@mm
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VBS.Haptime.B@mm is a Visual Basic Script (VBS) worm. It infects .htm, .html, .vbs, .asp, and .htt files. It replicates using MAPI objects to spread itself as an attachment. The worm attaches itself to all outgoing messages using the stationery feature of Microsoft Outlook Express.

This is a variant of VBS.Haptime.A@mm. The difference between VBS.Haptime.A@mm and VBS.Haptime.B@mm is the name of the attachment file, which is changed from Untitled.htm to Instlog.htm.

The worm utilizes a known Microsoft Outlook Express security hole so that the worm is executed without having to run any attachment. Microsoft has patched this security hole that eliminates security vulnerabilities in "Scriptlet.TypLib" ActiveX controls. The patch is available at:

If you have a patched version of Outlook Express, this worm will not work automatically.

Antivirus Protection Dates

  • Initial Rapid Release version 15 June 2001
  • Latest Rapid Release version 28 September 2010 revision 054
  • Initial Daily Certified version 15 June 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.

VBS.Haptime.B@mm is a viral Visual Basic Script contained in an .htm, .vbs, .asp, or .htt file. It utilizes the stationery feature of Outlook Express. Stationery is used as an HTML-formatted new message template, which permits you to change the background and fonts used in the message. The worm attempts to replicate by setting HTML as the default message format and setting an infected HTML page as the default stationery for Outlook Express. This is similar to the Wscript.KakWorm action, when any outgoing message sent from an infected computer will include the viral script in its HTML-formatted body. This worm can infect the computer if it is displayed in the preview pane of Outlook Express. This can happen when switching between folders without having to open an attachment. This can be prevented by applying Microsoft's security update patch.

When executed, the script performs the following actions:
  1. It drops itself as Help.hta, Help.vbs, Help.htm, or Instlog.htm file.
  2. It adds the registry key


    and updates a value with a count of the number of infected files.
  3. The script then looks for .htm, .vbs, .asp, and .htt files in all folders on both local and mapped drives. If the sum of the current day and the current month is 13, then the script tries to delete all .exe and .dll files.
  4. For each file that it finds, VBS.Haptime.B@mm looks for a "mailto:<email address>" string inside of the file, retrieves the email address, and sends the following message to that address:

    Subject: Help
    Message: (The body of the message is empty.)
    Attachment: Instlog.htm (This is infected with VBS.Haptime.B@mm.)
  5. Next, if the file that provided the worm with the email address is an .htm, .vbs, .asp, or .htt file, it becomes infected with the viral script. The name of this file is stored in the registry key

  6. On every 366th infection, the script performs one of the following two actions with equal probability:
      • It looks for messages stored in the Inbox, and replies to all of them with the following message:

        Subject: Fw: <The original sender's email address>
        Message: (The body of the message is empty.)
        Instlog.htm (This is infected with VBS.Haptime.B@mm.)
      • It sends out the following message to all email addresses found in the default Contacts folder:

        Subject: Help
        Message: (The body of the message is empty.)
        Attachment: Instlog.htm (This is infected with VBS.Haptime.B@mm.)
  7. The script sets a new default desktop wallpaper to display an infected Help.htm page to enable itself to run at startup. To hide itself, the infected Active Desktop wallpaper page tries to use the same desktop background picture that was there before the infection.
  8. The script infects the .htt files in the <Windows>\Web folder. The HyperText template files are used to help you design the content and the look of your folders. If you have enabled Windows to view folders as Web pages, the viral script is executed every time that a folder is viewed.
  9. The worm sets HTML as the default message format. It then sets the infected <Windows>\Instlog.htm file as the default stationery for Microsoft Outlook Express. Any message sent from Outlook Express will contain the worm embedded into its HTML-formatted body. To provide this kind of replication, the worm creates the values

    Message Send HTML    1
    Compose Use Stationery    1
    Stationery Name    Windows\instlog.htm

    in the registry key

    HKEY_CURRENT_USER\Identities\<Default User ID>\
    Software\Microsoft\Outlook Express\5.0\Mail

    NOTE: If your email program or the email server that handles the message is not set up for or capable of handling HTML-encoded messages, the program or server will convert the encoded message to an attachment. If you open the attachment, it can have the same effect as if you received the email message with the worm embedded.


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.

SARC has developed a tool to remove the changes that were made to a computer by the VBS.Haptime.A@mm and VBS.Haptime.B@mm worms. To obtain the VBS.Haptime Fix tool , go to:

Manual removal
To remove this worm manually,delete .htt files and any files detected as VBS.Haptime.b@mm, delete the registry keys that it added, and reset your Outlook Express settings.

To remove the worm:
  1. Run LiveUpdate to make sure that you have the most recent virus definitions.
  2. Start Norton AntiVirus (NAV), and run a full system scan, making sure that NAV is set to scan all files.
  3. Delete any files detected as VBS.Haptime.B@mm.

To delete .htt files:
  1. Using windows Explorer, browse to C:\Windows Web

    NOTE: If Windows is installed in a different location, make the appropriate path substitution.
  2. Click Start, point to Find, and then click Search or "Files or Folders."
  3. Make sure that "Look in" is set to C:\Windows Web.
  4. In the "Named" or "Search for..." box, type--or copy and paste--the following file name:

  5. Click Find Now or Search Now.
  6. Delete the files that are found.

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.
  1. Click Start, and click Run. The Run dialog box appears.
  2. Type regedit and click OK. The Registry Editor opens.
  3. Navigate to and delete the following keys:


4. Exit the Registry Editor

To reset Microsoft Outlook Express:
  1. Start Outlook Express.
  2. Click Tools, and click Options.
  3. Click the Compose tab.
  4. In the Stationery section, if you do not use stationery when sending email, uncheck Mail. Otherwise, click Select and select the stationery that you want to use.

Writeup By: Kaoru Hayashi