Threat Explorer

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VBS.Pila@mm

VBS.Pila@mm

Discovered:
17 January 2002
Updated:
13 February 2007
Also Known As:
VBS.Pilantra, VBS/Rols.dr@mm, VBS/Pulga.A@mm, VBS.Karmahotel, VBS/Estufa.Worm

This virus is coded in Visual Basic Script (VBS). To distribute itself, it attempts to modify mIRC scripts, copy itself to drives across the local network, and send itself using Microsoft Outlook.

Antivirus Protection Dates

  • Initial Rapid Release version 17 January 2002
  • Latest Rapid Release version 28 September 2010 revision 054
  • Initial Daily Certified version 17 January 2002
  • 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.

If it is executed, VBS.Pila@mm does the following:

It creates the file Platônico.txt, adds text that is hard-coded in the virus to the file, and then opens the file using Notepad. The text describes in Portuguese how a lover was jilted and would exact revenge, calling the other lover a "cursed flea."

It next checks if the file C:\File0004.chk exists. If it does not, then the virus copies itself to the Windows folder as Explorer.dll.vbs.

It attempts to modify the [boot] of the System.ini file so that it loads when you start Windows.

This script will then create a copy of itself in as \Windows\Platônico.txt <76 spaces> .shs

NOTE: The use of many spaces between a double extension is used by virus writers to make you think that an executable file is really a harmless text file.

Next, it attempts to perform a mass mailing of the Platônico.txt <76 spaces> .shs file using Microsoft Outlook. The email has the following characteristics:

Subject: This will be one of the following, chosen at random:

Texto imperdível!
Texto muito engraçado!
O melhor texto que li nos últimos tempos...

Message:
................................................
Olá!!"
Não posso falar muito sobre o texto porque se não perde a graça, é uma história de amor platônico... Achei muito engraçado vale a pena!!"
....  .... .  .....    .....  ....  . ...   .....
..... ....   ....  .     .  ....    .....  ....

The script then writes its "marker" file by creating C:\File0004.chk. The file consists of one line:

Estufa co.

This script then attempts to connect to mapped drives across a network and write itself as the file named Pulga.txt.shs

It also tries to modify the Script.ini file that is used by the mIRC chat clients to distribute itself when you join Internet Relay Chat channels. The mIRC script is modified to connect to the IRC channel irc.libnet.com.br and send a notification alert that the victim has become infected.

This script also drops two VBS files:
  • C:\File0001.chk.vbs This file will scan the local drive and create a listing of subfolders on the system.
  • C:\file0002.chk.vbs. This file will scan the local drive and create a listing of files found on the system.

These listings are then made available to a hacker using mIRC.

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.

Run LiveUpdate to make sure that you have the most recent virus definitions.
  1. Start Norton AntiVirus (NAV), and make sure that NAV is configured to scan all files. For instructions on how to do this, read the document How to configure Norton AntiVirus to scan all files.
  2. Run a full system scan.
  3. Delete all files that are detected as IRC.Pila.


Writeup By: Patrick Nolan