Downloader.Ject.C

SUMMARY

Downloader.Ject.C is a variant of Download.Ject that attempts to download and execute files by exploiting two vulnerabilities in Internet Explorer (described in Microsoft Security Bulletin MS04-013).

The Trojan is triggered by opening an email that contains the exploit HTML code.

Note: Virus definitions dated June 7th, 2006 or earlier may detect this threat as Download.Ject.C.

Behavior

Symptoms

Transmission

Protection

• Virus Definitions (LiveUpdate™ Weekly) August 31, 2004
• Virus Definitions (Intelligent Updater) August 28, 2004

Threat Assessment

Wild

• Wild Level: Low
• Number of Infections: 0 - 49
• Number of Sites: More than 10
• Geographical Distribution: Low
• Threat Containment: Easy
• Removal: Moderate

Damage

• Damage Level: Medium
• Compromises Security Settings: Terminates processes related to various security programs.

Distribution

• Distribution Level: Low

TECHNICAL DETAILS

When Downloader.Ject.C is executed, it performs the following actions:

1. Downloads and opens default.chm, from the domain named www.vikord.com , using the Microsoft Outlook Express MHTML URL Processing Vulnerability (described in Microsoft Security Bulletin MS04-013).
   
2. Downloads an executable named default.exe, using the ADODB.Stream object vulnerability, and saves it as one of the following:
   
   • C:ProgrammerWindows Media Playerwmplayer.exe
   • C:ProgramWindows Media Playerwmplayer.exe
   • C:ProgrammeWindows Media Playerwmplayer.exe
   • C:ProgrammiWindows Media Playerwmplayer.exe
   • C:ProgramfilerWindows Media Playerwmplayer.exe
   • C:ProgramasWindows Media Playerwmplayer.exe
   • C:Archivos de programaWindows Media Playerwmplayer.exe
   • C:Program FilesWindows Media Playerwmplayer.exe
     
     
3. Executes the wmplayer.exe file, which creates following files:
   
   • %System%doriot.exe (A copy of itself.)
   • %System%gdqfw.exe (A downloader module.)
     
     Note: %System% is a variable that refers to the System folder. By default this is C:WindowsSystem (Windows 95/98/Me), C:WinntSystem32 (Windows NT/2000), or C:WindowsSystem32 (Windows XP).
     
     
4. Adds the value:
   
   "wersds" = "%System%doriot.exe"
   
   to the registry keys:
   
   HKEY_CURRENT_USERSoftwareMicrosoftWindowsCurrentVersionRun
   HKEY_LOCAL_MACHINESoftwareMicrosoftWindowsCurrentVersionRun
   
   so that the Trojan runs when you start Windows.
   
   
5. Injects gdqfw.exe into Explorer.exe as a remote thread. This thread attempts to do the following:
   
   1. Stops the SharedAccess service and then sets the Startup type of this service to Disabled.
      
      Note: The SharedAccess service is also known by the following names:
      
      • Windows XP Service Pack 2:
        Windows Firewall/Internet Connection Sharing (ICS)
      • Windows XP Service Pack 1 or earlier:
        Internet Connection Firewall (ICF) / Internet Connection Sharing (ICS)
      • Windows 2000:
        Internet Connection Sharing (ICS)
        
        
   2. Terminates the following process:
      
      • ATUPDATER.EXE
      • AUPDATE.EXE
      • AUTODOWN.EXE
      • AUTOTRACE.EXE
      • AUTOUPDATE.EXE
      • AVPUPD.EXE
      • AVWUPD32.EXE
      • AVXQUAR.EXE
      • CFIAUDIT.EXE
      • DRWEBUPW.EXE
      • ESCANH95.EXE
      • ESCANHNT.EXE
      • FIREWALL.EXE
      • ICSSUPPNT.EXE
      • ICSUPP95.EXE
      • LUALL.EXE
      • MCUPDATE.EXE
      • NUPGRADE.EXE
      • OUTPOST.EXE
      • UPDATE.EXE
        
        
   3. The Trojan attempts to download a file from one of the following domains. The file is saved as %Windir%\_re_file.exe and then executed.
      
      Note: %Windir% is a variable that refers to the Windows installation folder. By default, this is C:Windows or C:Winnt.
      
      • allianzsp.sk
      • coolweb.psg.sk
      • cryofthespirit.com
      • dollypop.com
      • execpage.com
      • helpdemos.com
      • helpingyouth.org
      • jamesbronner.com
      • koti.pl
      • miracle.v6.cz
      • mountainwings.com
      • mountainwings4.com
      • naturalpros.com
      • oracal.pl
      • shock.evernet.com.pl
      • SportLine.go.ro
      • stroipolymer.ru
      • theonlineword.com
      • virtualchurch.com
      • visionforsouls.org
      • wingsoverlife.com
      • www.1800thewoman.com
      • www.1944.pl
      • www.45partsdepot.com
      • www.7pe.friko.pl
      • www.air-computers.com.ar
      • www.ametist.spb.ru
      • www.apodis.pl
      • www.arrasy.pl
      • www.arthurspeaks.com
      • www.astermed.pl
      • www.atomique.pl
      • www.atw.hu
      • www.avatar.ee
      • www.avers.com.pl
      • www.baltexpo.spb.ru
      • www.bomart.cz
      • www.bravo.gliwice.pl
      • www.bronnerbros.com
      • www.buycare.com
      • www.cumparacd.go.ro
      • www.da-rom.co.il
      • www.domu.net
      • www.eastandard.co.ke
      • www.elblu.republika.pl
      • www.elcorsy.com
      • www.elite-style.com
      • www.enduser1.fast.net
      • www.enitex.by
      • www.enitex-m.by
      • www.eris.pl
      • www.europharm.pl
      • www.extreme-racing.lg.ua
      • www.fotel.pl
      • www.fotolab.sk
      • www.frater.hu
      • www.gardameditech.com
      • www.generex.de
      • www.goldgates.com
      • www.goodboy.dem.ru
      • www.hards.pl
      • www.healthcometh.com
      • www.holz-studio.at
      • www.ibplus.sk
      • www.icpnet.pl
      • www.icpnet.pl
      • www.inlan.sk
      • www.jamesbronner.com
      • www.jbplus.cz
      • www.justmatchit.com
      • www.kubtelecom.ru
      • www.kuda.com.ua
      • www.lacittadifiorenzuola.it
      • www.lotusdog.net
      • www.ltvo.spb.ru
      • www.master.pl
      • www.members.aon.at
      • www.moteplassen1.com
      • www.mountainwings2.com
      • www.multifoto.sk
      • www.nadodrze.pl
      • www.nairobiwebspace.com
      • www.nameitright.com
      • www.nardo.bbe.pl
      • www.netland.gda.pl
      • www.netta.pl
      • www.nikola.piwko.pl
      • www.ntrlab.com
      • www.nustep.sk
      • www.octava.pl
      • www.odevnictvo.sk
      • www.oftza.friko.pl
      • www.oktbroiler.ru
      • www.online40.com
      • www.online50.com
      • www.oto.lv
      • www.pancoopzsv.co.yu
      • www.pay5495.com
      • www.pc-hard.com.ua
      • www.perfect-beauty.at
      • www.pharmag.pl
      • www.polsl.katowice.pl
      • www.prophetcollins.com
      • www.propi.cz
      • www.pursuit.rv.ua
      • www.pyrlandia-boogie.pl
      • www.quatro.sk
      • www.r-bazar.ru
      • www.roszkowski.pl
      • www.silvic.ro
      • www.sincron.go.ro
      • www.skylive.pl
      • www.smgkrc.pl
      • www.soulring.com
      • www.star-max.it
      • www.sunbud.com.pl
      • www.swez.net
      • www.system5electronics.com
      • www.tcvwebtv.com.ar
      • www.thewoman.com
      • www.tivis.cz
      • www.ukpl.pl
      • www.vacation-network.net
      • www.wyspian.iap.pl
      • www.zasada-rowery.pl

Recommendations

Symantec Security Response encourages all users and administrators to adhere to the following basic security "best practices":

• Turn off and remove unneeded services. By default, many operating systems install auxiliary services that are not critical, such as an FTP server, telnet, and a Web server. These services are avenues of attack. If they are removed, blended threats have less avenues of attack and you have fewer services to maintain through patch updates.
• If a blended 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 (for example, all Windows-based computers should have the current Service Pack installed.). Additionally, please apply any security updates that are mentioned in this writeup, in trusted Security Bulletins, or on vendor Web sites.
• 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.
• Configure your email server to block or remove email that contains file attachments that are commonly used to spread viruses, such as .vbs, .bat, .exe, .pif and .scr files.
• Isolate infected computers quickly to prevent further compromising your organization. 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.

REMOVAL

The following instructions pertain to all current and recent Symantec antivirus products, including the Symantec AntiVirus and Norton AntiVirus product lines.

1. Disable System Restore (Windows Me/XP).
2. Update the virus definitions.
3. Restart the computer in Safe mode or VGA mode.
4. Run a full system scan and delete all the files detected as Downloader.Ject.C.
5. Delete the value that was added to the registry.
6. Re-enable the SharedAccess service.
   

For specific details on each of these steps, read the following instructions.

1. To disable System Restore (Windows Me/XP)
If you are running Windows Me or Windows XP, we recommend that you temporarily turn off System Restore. Windows Me/XP uses this feature, which is enabled by default, to restore the files on your computer in case they become damaged. If a virus, worm, or Trojan infects a computer, System Restore may back up the virus, worm, or Trojan on the computer.

Windows prevents outside programs, including antivirus programs, from modifying System Restore. Therefore, antivirus programs or tools cannot remove threats in the System Restore folder. As a result, System Restore has the potential of restoring an infected file on your computer, even after you have cleaned the infected files from all the other locations.

Also, a virus scan may detect a threat in the System Restore folder even though you have removed the threat.

For instructions on how to turn off System Restore, read your Windows documentation, or one of the following articles:

• "How to disable or enable Windows Me System Restore"
• "How to turn off or turn on Windows XP System Restore"

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Note: When you are completely finished with the removal procedure and are satisfied that the threat has been removed, re-enable System Restore by following the instructions in the aforementioned documents.

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For additional information, and an alternative to disabling Windows Me System Restore, see the Microsoft Knowledge Base article, "Antivirus Tools Cannot Clean Infected Files in the _Restore Folder," Article ID: Q263455.

2. To update the virus definitions
Symantec Security Response fully tests all the virus definitions for quality assurance before they are posted to our servers. There are two ways to obtain the most recent virus definitions:

• Running LiveUpdate, which is the easiest way to obtain virus definitions: These virus definitions are posted to the LiveUpdate servers once each week (usually on Wednesdays), unless there is a major virus outbreak. To determine whether definitions for this threat are available by LiveUpdate, refer to the Virus Definitions (LiveUpdate).
  
  

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  Note: If this Trojan is running, you may not be able to run LiveUpdate. If you cannot, download the definitions using the Intelligent Updater (see the next bulleted item).

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• Downloading the definitions using the Intelligent Updater: The Intelligent Updater virus definitions are posted on U.S. business days (Monday through Friday). You should download the definitions from the Symantec Security Response Web site and manually install them. To determine whether definitions for this threat are available by the Intelligent Updater, refer to the Virus Definitions (Intelligent Updater).
  
  The Intelligent Updater virus definitions are available: Read "How to update virus definition files using the Intelligent Updater" for detailed instructions.

3. To restart the computer in Safe mode or VGA mode
Shut down the computer and turn off the power. Wait for at least 30 seconds, and then restart the computer in Safe mode or VGA mode.

• For Windows 95, 98, Me, 2000, or XP users, restart the computer in Safe mode. For instructions, read the document, "How to start the computer in Safe Mode."
• For Windows NT 4 users, restart the computer in VGA mode.

4. To scan for and delete the infected files

1. Start your Symantec antivirus program and make sure that it is configured to scan all the files.
   • For Norton AntiVirus consumer products: Read the document, "How to configure Norton AntiVirus to scan all files."
   • For Symantec AntiVirus Enterprise products: Read the document, "How to verify that a Symantec Corporate antivirus product is set to scan all files."
2. Run a full system scan.
3. If any files are detected as infected with Downloader.Ject.C, write down the location and file name, and then click Delete.

5. To delete the value from the registry

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WARNING: Symantec strongly recommends that you back up the registry before making any changes to it. Incorrect changes to the registry can result in permanent data loss or corrupted files. Modify the specified keys only. Read the document, "How to make a backup of the Windows registry," for instructions.

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1. Click Start, and then click Run. (The Run dialog box appears.)
2. Type regedit
   
   Then click OK. (The Registry Editor opens.)
   
   
3. Navigate to the key:
   
   HKEY_CURRENT_USERSoftwareMicrosoftWindowsCurrentVersionRun
   
   
4. In the right pane, delete the value:
   
   "wersds" = "%System%doriot.exe"
   
   
5. Navigate to the key:
   
   HKEY_LOCAL_MACHINESoftwareMicrosoftWindowsCurrentVersionRun
   
   
6. In the right pane, delete the value:
   
   "wersds" = "%System%doriot.exe"
   
   
7. Exit the Registry Editor.

6. To re-enable the SharedAccess service
(Windows 2000/XP only)
The SharedAccess service is responsible for maintaining Internet Connection Sharing and the Windows Firewall/Internet Connection Firewall applications in Windows. (The presence and names of these applications varies depending on the operating system and service pack you are using.) In order to protect your PC and maintain network functionality, you will need to re-enable this service if you are using any of these applications.

In order to re-enable the SharedAccess service, complete the following steps:

Windows XP Service Pack 2
If you are running Windows XP with Service Pack 2 and are using the Windows Firewall, the operating system will alert you when the SharedAccess service is stopped by displaying an alert balloon saying that your Firewall status is unknown. Follow these steps to ensure that the Windows Firewall is re-enabled:

1. Click Start > Control Panel. The Control Panel appears.
   
   
2. Double-click the Security Center. The Windows Security Center appears.
   
   
3. Ensure that the Firewall security essential is marked ON.
   
   Note: If the Firewall security essential is marked on, your Windows Firewall is on and do not need to continue these steps.
   
   If it is not marked ON, click the Recommendations... button. The Recommendation window appears.
   
   
4. Under "Recommendation," click Enable Now. A window appears telling you that the Windows Firewall was successfully turned on.
   
   
5. Click Close and then click OK.
   
   
6. Close the Security Center.

Windows 2000 or Windows XP Service Pack 1 or earlier
Complete the following steps to re-enable the SharedAccess service:

1. Click Start > Run.
2. Type services.msc
   
   Then click OK.
   
   The Services window appears.
   
   
3. In Windows 2000:
   Under the Name column, locate the "Internet Connection Sharing (ICS)" service and double-click it.
   
   In Windows XP:
   Under the Named column, locate the "Internet Connection Firewall (ICF) / Internet Connection Sharing (ICS)" service and double-click it.
   
   
4. Under "Startup Type:", select "Automatic" from the drop-down menu.
   
   
5. Under "Service Status:", click the Start button.
   
   
6. Once the service has completed starting, click OK.
   
   
7. Close the Services window.