W32.Paroc.Worm

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Discovered: June 11, 2002
Updated: February 13, 2007 11:39:14 AM
Type: Worm
Systems Affected: Windows


W32.Paroc.Worm uses MAPI to send itself to email addresses that it finds in HTML files. The email contains this message:

Attach file is new multimedia pack
for Win9x/ME/NT/2000 and some WinXP!

(c) Copyright PROSAC SW

and will appear to come from "PROSAC SW" <prosac@bugs.com>.

Antivirus Protection Dates

  • Initial Rapid Release version June 12, 2002
  • Latest Rapid Release version September 28, 2010 revision 054
  • Initial Daily Certified version June 12, 2002
  • Latest Daily Certified version September 28, 2010 revision 036
  • Initial Weekly Certified release date June 12, 2002

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

Writeup By: Peter Ferrie

Discovered: June 11, 2002
Updated: February 13, 2007 11:39:14 AM
Type: Worm
Systems Affected: Windows


When the worm is run, it does the following:

It checks whether the operating system is Windows 2000.

  • If it is Windows 2000, the worm attempts to start the Tapi32ms service, which, if it exists, will have been created by previous instances of the worm. If the service cannot be started, then the worm copies itself as \%System%\Tapi32.exe, which creates the Tapi32ms service.
  • If the operating system is Windows 98/Me, the worm registers as a service and adds itself to the registry key

    HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\RunServices

    as
    PROSAC %system%\tapi32.exe

The worm creates the file \%Windows%\Prosac.rar, which contains the worm itself. The worm then attempts to send the .rar file to the virus author.

NOTES:
  • %Windows% is a variable. The worm locates the \Windows folder (by default this is C:\Windows or C:\Winnt) and copies itself to that location.
  • %System% is a variable. The worm locates the \Windows\System folder (by default this is C:\Windows\System or C:\Winnt\System32) and copies itself to that location.

Next, the worm searches all subfolders under \%cache% for .htm* files. For each of these files that contains a "mailto:" string, the worm sends the .rar file to the mailto: address. The email contains this message:

Attach file is new multimedia pack
for Win9x/ME/NT/2000 and some WinXP!

(c) Copyright PROSAC SW

and will appear to come from "PROSAC SW" <prosac@bugs.com>.

If the computer has an active Internet connection, then the worm downloads and runs the Sender.exe file from the virus author's Web site.

If this is the first time the worm has run, then the worm displays a message that tells the user to reboot the computer.

Recommendations

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: Peter Ferrie

Discovered: June 11, 2002
Updated: February 13, 2007 11:39:14 AM
Type: Worm
Systems Affected: Windows


To remove this worm, update the virus definitions, run a full system scan, and delete all files that are detected as W32.Paroc.Worm. For details on how to do this, read the following instructions.

To scan with Norton AntiVirus and delete the infected files:

  1. Obtain the most recent virus definitions. There are two ways to do this:
    • Run LiveUpdate, which is the easiest way to obtain virus definitions. These virus definitions have undergone full quality assurance testing by Symantec Security Response and are posted to the LiveUpdate servers one time each week (usually Wednesdays) unless there is a major virus outbreak. To determine whether definitions for this threat are available by LiveUpdate, look at the Virus Definitions (LiveUpdate) line at the top of this write-up.
    • Download the definitions using the Intelligent Updater. Intelligent Updater virus definitions have undergone full quality assurance testing by Symantec Security Response. They are posted on U.S. business days (Monday through Friday). They must be downloaded from the Symantec Security Response Web site and installed manually. To determine whether definitions for this threat are available by the Intelligent Updater, look at the Virus Definitions (Intelligent Updater) line at the top of this write-up.

      Intelligent Updater virus definitions are available here. For detailed instructions on how to download and install the Intelligent Updater virus definitions from the Symantec Security Response Web site, click here.
  2. Start Norton AntiVirus (NAV), and make sure that NAV is configured to scan all files.
  3. Run a full system scan.
  4. Delete all files that NAV detects as W32.Paroc.Worm.


Writeup By: Peter Ferrie