W32.Formshared.A

Risk Level 1: Very Low

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Discovered: January 2, 2007

Updated: February 13, 2007 1:03:05 PM

Type: Worm

Systems Affected: Windows 2000, Windows 95, Windows 98, Windows Me, Windows NT, Windows Server 2003, Windows XP

When the worm executes, it performs the following actions:

Copies itself to the following location:

%Windir%\checkers5.exe

Note: %Windir% is a variable that refers to the Windows installation folder. By default, this is C:\Windows or C:\Winnt.
Adds the value:

"checkers" = "%Windir%\checkers5.exe"

to the registry subkey:

HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Run

so that it executes whenever Windows starts.
Creates the following folder, if it does not already exist:

%Windir%\Shared
Creates a number of .zip files containing an Infostealer in the above folder.
Randomly selects a name for the .zip file from a large list, including the following:
- @Stake LC4 v4.00 by JustJack.czip
- @stake LC 5 v5.02.czip
- !Tankz Battle in the City v1.1 for PalmOS.czip
- $Test v1.2.005.czip
- @udio Organizer v1.5 German.czip
- @udio Organizer v1.11 German.czip
- @uto-M@iler 2001 v1.0.24.czip
- 1+2.czip
- 1941 Operation Typhoon v1.0c.czip
- 1939 BattleFleet v1.55.czip
- 1939 BattleFleet v1.20.7.czip
- 18 Wheels Of Steel Pedal To The Metal by iND.czip
- 18 Wheels Of Steel Pedal To The Metal by Revelation.czip
- 18 Wheels of Steel Pedal to the Metal v1.07.czip
- 168 Digital Mixer Editor.czip
- 15 Slide 1.00.czip
- 15-Pack v1.29.czip
- 15-Pack v1.25 by Core.czip
- 15-Pack v1.25 by RP2K.czip
- 15-Pack v1.25 by TSRH.czip
- 1475 Leonardo da Vinci Calculator v1.22.czip
- 1475 Leonardo da Vinci Calculator v1.21 by Raid.czip
- 1475 Leonardo da Vinci Calculator v1.21 by TNT.czip
- 1-4-All HTML Editor 2.10.czip
- 13 Photos de Sandra Bullock Denudee ScreenSaver.czip
- 12!The Series... Pyramid 1.0.czip
- 128Gamma Encryption v3.0.czip
- 128Gamma Encryption v3.0c.czip
- 12345-Wizard v1.25.czip
- 123 Audio CD Ripper v2.10.czip
- 123 Audio CD Ripper v1.80.czip
- 123 AVI to GIF v1.0.czip
- 123 CD Extractor v1.50.czip
- 123 CD Ripper v1.50.czip
- 123 CD to MP3 Ripper v1.60.czip
- 123 File Splitter v4.0 by LasH.czip
- 123 File Splitter v4.0 by RP2K.czip
- 123 Flash Chat v3.0.czip
- 123 Flash Me 2.0 build 141 Keyfile.czip
- 123 Flash Me 2.0 build 141 Keygen.czip
- 123 Flash Me 2.0 build 132.czip
- 123 Flash Menu v1.02.czip
- 123 GIF-JPG Optimizer.czip
- 123 Graphic Converter v2.1.8.48.czip
- 123 Graphic Converter v1.5.czip
- 123 Graphic Converter XP v3.0.0.1.czip
- 123 Hidden Sender v2.41.czip
- 123 Icon Hunter v1.0.czip
- 123 MP3 WAV Converter and Player v3.1.czip
- 123 MP3 WAV Converter v3.1 by Scorpion.czip
- 123 MP3 WAV Converter v3.1 by TSRH.czip
- 123 Outlook Express Backup Enterprise Edition v1.10.052604.czip
- 123 Outlook Express Backup v1.02 by Quartex.czip
- 123 Outlook Express Backup v1.02 by SND.czip
- 123 Passwords 98 v1.0.czip
- 123 PosiTrax v1.02.czip
- 123 ScreenSaver Maker v3.0 by RP2K.czip
- 123 ScreenSaver Maker v3.0 by Scorpion.czip
- 123 ScreenSaver Maker v3.0 by TSRH.czip
- 123 Screensaver Maker v2.2.czip
- 123 Screensaver Maker v2.2 Crack by SND.czip
- 123 Screensaver Maker v2.2 Keygen by SND.czip
- 123 Sound Recorder v1.60.czip
  
  Note: Each of these .zip files will contain the following:
  - An executable file with the same name as the .zip file (a copy of Infostealer)
  - readme.txt
  - [RANDOM NAME].dll
Registers its file-sharing application on the compromised computer at the following servers:
- 72.51.38.140:8118
- 80.239.200.109:3000
- 213.251.133.129:6567
- 80.239.200.108:3000
- 209.204.61.161:10000
- 62.241.53.3:4242
- 72.51.37.237:8899
- 62.241.53.2:4242
- 209.204.61.170:6789
- 209.204.61.119:6611
- 62.241.53.16:4242
- 72.51.38.142:7822
- 209.204.61.178:6000
- 66.172.60.129:4661
- 209.204.61.110:4661
- 209.204.61.150:4611
- 209.204.61.124:4000
- 66.172.60.138:5000
- 72.51.35.78:7999
- 209.204.61.97:6006
- 62.241.53.17:4242
- 66.172.60.130:4661

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: Sean Kiernan

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