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Discovered: May 10, 2001
Updated: February 13, 2007 11:36:29 AM
Type: Virus

W32.HLLC.Danny is a simple Win32 virus that overwrites .exe files. The virus saves a copy of the original file before overwriting it. When the virus is executed, it displays a message containing a quote from Shakespeare's Hamlet.

Antivirus Protection Dates

  • Initial Rapid Release version May 10, 2001
  • Latest Rapid Release version September 28, 2010 revision 054
  • Initial Daily Certified version May 10, 2001
  • Latest Daily Certified version September 28, 2010 revision 036

Click here for a more detailed description of Rapid Release and Daily Certified virus definitions.

Writeup By: Neal Hindocha

Discovered: May 10, 2001
Updated: February 13, 2007 11:36:29 AM
Type: Virus

W32.HLLC.Danny is a companion virus written in a high-level language (HLLC). The virus is a simple overwriter. However, before it overwrites a file, it saves a copy of it. The name of the copy will be the original file name, but with the .iso extension.

When executed, the virus tries to find executable files to infect by going into a FindFirst -> FindNext loop, looking for any files with the .exe extension that are in the same folder as the virus.

Every time that W32.HLLC.Danny is executed, it displays the following message, which is from the play Hamlet, by William Shakespeare:

The virus does not attempt to execute the original file, so when an infected file is run, only the virus is executed.


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.

Writeup By: Neal Hindocha

Discovered: May 10, 2001
Updated: February 13, 2007 11:36:29 AM
Type: Virus

To remove this virus, delete files detected as W32.HLLC.Danny, and then rename the copies that the virus backed up so that they again have the .exe file extension.

To remove this virus:

  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 W32.HLLC.Danny. However, before deleting each file, write down the file name.

To rename the files:
  1. Click Start, point to Find or Search, and click Files or Folders.
  2. Make sure that "Look in" is set to (C:) (or the drive on which the infected files were found, if different), and that Include subfolders is checked.
  3. In the "Named" or "Search for..." box, type

  4. Click Find Now or Search Now.
  5. For each file that is found:
    1. Make sure that the file name (not the extension) is on the list of files that you wrote down previously. (It is likely that all .iso files will be the files that were renamed by the virus, as .iso is not a common file extension. However, because it is possible that it could be a legitimate extension for some program, we suggest that you do check it against your list.)
    2. Right-click the file, and click Rename.
    3. Rename only the file extension from .iso to .exe.

Writeup By: Neal Hindocha