Threat Explorer

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13 February 2001
13 February 2007
Also Known As:
Macro.Office.Hopper.n, X97M/Hopper.r

O97M.Hopper.V is a stealth macro virus that infects both Microsoft Word documents and Microsoft Excel workbooks. Depending on the day of the month, O97M.Hopper.V may modify data or settings in the Word document or in the Excel workbook.

The process that O97M.Hopper.V uses for Microsoft Word documents and for Microsoft Excel workbooks is described separately.

Microsoft Excel
On deactivation of an infected workbook, the file Book1 is inserted in the \XLStart folder. Then the virus infects Word's template so that the virus will be spread to Word documents.

The Excel payload is dependent upon the day of the month.
  • If the day of the month is 1, then there is a 1 in 10 chance that 10 random cells selected from the first 100 rows and 100 columns will have the comment "Cross.BadSeed v0.41" added to it.
  • If the day of the month is 10, then there is a 1 in 3 chance that 150 cell pairs are exchanged. These cells are selected from Column 2 to Column 16 and Row 10 to Row 209.
  • If the day of the month is 15, then the author name is set to "1nternal"
  • If the day of the month is 20, then there is a 1 in 5 chance that the status bar displays "Cross.BadSeed v0.41 /1nternal"

Microsoft Word
Whey you close an infected document, the virus stealths by deactivating the following options: Save Normal Prompt, Confirm Conversions, and Virus Protection. The virus then checks to see if the template is already infected. If it is not, then it is infected by copying the viral code from the active document to the template.

Next, the Microsoft Excel \XLStart folder is checked for the presence of the (infected) workbook, Book 1. If this file does not exist, the virus protection option in Excel is deactivated by manipulating the corresponding registry entry, and the Book1 file is inserted in the \XLStart folder, and it is then infected.

After is checked, the active document is inspected. If it is not infected, the virus copies its code from to the active document.

The Word payload, like the Excel payload, is dependent upon the day of the month.
  • If the day of the month is 1, then there is a 1 in 10 chance that all instances of the character "I" (upper case 'i') in the active document will be changed to "1."
  • If the day of the month is 5, then there is a 1 in 10 chance that all instances of the word "not" in the active document will be deleted.
  • If the day of the month is 10, then there is a 1 in 15 chance that the Office Assistant will activate with a text balloon.

    The balloon heading reads:
    "Cross.BadSeed v0.41"

    The balloon text reads:
    "Programmer:        1nternal"
    "Class Infection:    VicodenES"
    "ActiveX Concept: 1nternal"
    "Book1. Concept:  VicodenES"
    "1nternal also wishes to thank all contributors and supporters which have made Cross.BadSeed possible."
  • If the day of the month is 15, then there is a 1 in 10 chance that the virus will attempt to connect to the Web site
  • If the day of the month is 20, then there is a 1 in 5 chance that the status bar displays "Cross.BadSeed v0.41 /1nternal."


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 recover from this infection:
  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. If any files are detected as infected by O97M.Hopper.V, click Repair.

Writeup By: Andre Post