Symantec Security Response
http://securityresponse.symantec.com

Trojan.Gamqowi

Discovered on: October 20, 2005

Last Updated on: March 13, 2006 10:45:41 PM

Trojan.Gamqowi is a Trojan horse that opens a back door and lowers security settings on the compromised computer. It also attempts to end security-related processes.
Removal tool link: http://securityresponse1.symantec.com/sarc/sarc.nsf/html/w32.secefa.removal.tool.html

Type: Trojan Horse

Infection Length: 159,744 bytes

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

protection

Virus Definitions (LiveUpdate™ Plus)

October 20, 2005

Virus Definitions (LiveUpdate™ Daily)

October 20, 2005

Virus Definitions (LiveUpdate™ Weekly)

October 26, 2005

Virus Definitions (Intelligent Updater)

October 20, 2005

Wild

Threat Metrics

Wild: Low	Damage: Low	Distribution: Low

Damage

Payload Trigger: n/a
Payload: Opens back door.
- Large scale e-mailing: n/a
- Deletes files: n/a
- Modifies files: Adds entries to hosts file.
- Degrades performance: n/a
- Causes system instability: n/a
- Releases confidential info: n/a
- Compromises security settings: Ends security-related programs and blocks access to security-related Web sites.

Distribution

When Trojan.Gamqowi is executed, it performs the following actions:

Creates the following mutex:

lmnla

so that only one instance of the Trojan will run on the compromised computer.
Copies itself as the following files:
- %Windir%\mwfirewall.exe
- %Windir%\svch0st.exe
  
  Note: %Windir% is a variable that refers to the Windows installation folder. By default, this is C:\Windows or C:\Winnt.
Drops the following files:
- %Windir%\mscore32.dll
- %Windir%\dodrrr.exe
- %Windir%\msconfl.dat
Attempts to remove the entry:

"devsec"

from the registry subkey:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
Attempts to remove the entries:

"sp0furl" "upurl" "sockport" "emsss" "emsrv"

from the registry subkey

HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer
Adds the value:

"ms_anti_spyware" = "%Windir%\mwfirewall.exe"

to the registry subkeys:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\RunOnceHKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\RunHKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\RunOnce

and the value:

"WINRUN" = "svch0st.exe"

to the registry subkeys:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\OLEHKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\LsaHKEY_CURRENT_USER\Software\Microsoft\OLEHKEY_CURRENT_USER\System\CurrentControlSet\Control\Lsa

so that it runs every time Windows starts.
Modifies the values:

"SFCDisable" = "0" "SFCScan" = "0"

in the registry subkey:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon

in order to disable Windows File Protection.
Adds the entries:

"lmnla" "veer" "mtxnm"

to the registry subkey:

HKEY_CURRENT_USER\SOFTWARE\Microsoft\Internet Explorer
Modifies the value:

"DisableRegistryTools" = "0"

in the registry subkeys:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies
Injects the following file into the process which created the Shell_TrayWnd window:

mscore32.dll
Attempts to end the following processes, some of which are security-related:
- ccapp.exe
- zapro.exe
- armor2net.exe
- ZAPRO.EXE
- amon.exe
- MpfService.exe
- zonealarm.exe
- outpost.exe
- firewall.exe
- atguard.exe
- tpfw.exe
- kpf4ss.exe
- mrt.exe
- NPROTECT.EXE
- kpf4gui.exewintbp.exe
- svnlitup32.exe
- service32.exe
- mousebm.exe
- llsrv.exe
- pnpsrv.exe
- winpnp.exe
- csm.exe
- system32.exe
- botzor.exe
- upnp.exe
- wintbpx.exe
- winshost.exe
- windll2.exe
- firewall_anti.exe
- wintbpx.exe
- FirewallSvr.exe
Blocks access to several security-related Web sites by appending the following text to the hosts file:

127.0.0.1 avp.com 127.0.0.1 ca.com 127.0.0.1 customer.symantec.com 127.0.0.1 dispatch.mcafee.com 127.0.0.1 download.mcafee.com 127.0.0.1 downloads-eu1.kaspersky-labs.com 127.0.0.1 downloads-us1.kaspersky-labs.com 127.0.0.1 downloads1.kaspersky-labs.com 127.0.0.1 downloads2.kaspersky-labs.com 127.0.0.1 downloads3.kaspersky-labs.com 127.0.0.1 downloads4.kaspersky-labs.com 127.0.0.1 f-secure.com 127.0.0.1 kaspersky-labs.com 127.0.0.1 kaspersky.com 127.0.0.1 liveupdate.symantec.com 127.0.0.1 liveupdate.symantecliveupdate.com 127.0.0.1 mast.mcafee.com 127.0.0.1 mcafee.com 127.0.0.1 microsoft.com 127.0.0.1 my-etrust.com 127.0.0.1 nai.com 127.0.0.1 networkassociates.com 127.0.0.1 oxyd.fr 127.0.0.1 pandasoftware.com 127.0.0.1 rads.mcafee.com 127.0.0.1 secure.nai.com 127.0.0.1 securityresponse.symantec.com 127.0.0.1 sophos.com 127.0.0.1 symantec.com 127.0.0.1 t35.com 127.0.0.1 t35.net 127.0.0.1 trendmicro.com 127.0.0.1 update.symantec.com 127.0.0.1 updates.symantec.com 127.0.0.1 us.mcafee.com 127.0.0.1 viruslist.com 127.0.0.1 virustotal.com 127.0.0.1 www.avp.com 127.0.0.1 www.ca.com 127.0.0.1 www.f-secure.com 127.0.0.1 www.grisoft.com 127.0.0.1 www.kaspersky.com 127.0.0.1 www.mcafee.com 127.0.0.1 www.microsoft.com 127.0.0.1 www.my-etrust.com 127.0.0.1 www.nai.com 127.0.0.1 www.networkassociates.com 127.0.0.1 www.oxyd.fr 127.0.0.1 www.pandasoftware.com 127.0.0.1 www.sophos.com 127.0.0.1 www.symantec.com 127.0.0.1 www.t35.com 127.0.0.1 www.t35.net 127.0.0.1 www.trendmicro.com 127.0.0.1 www.viruslist.com 127.0.0.1 www.virustotal.com
Connects to an IRC channel on the server 195.245.244.243 on TCP port 4661 and listens for commands that allow a remote attacker to perform any of the following actions:
- Obtain system information
- Download files
- Send e-mails
Downloads the following file from [http:]//qanmqqoiw.com/[REMOVED]/up.php:

%Windir%\ajlkqjlk.exe

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 using the Trojan.Gamqowi Removal Tool
Symantec Security Response has developed a removal tool to clean the infections of Trojan.Gamqowi. Use this removal tool first, as it is the easiest way to remove this threat.

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

Disable System Restore (Windows Me/XP).
Remove all the entries that the risk added to the hosts file.
Update the virus definitions.
Run a full system scan and delete all the files detected.
Delete any values added to the registry.

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:

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

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 remove all the entries that the risk added to the hosts file

Navigate to the following location:
- Windows 95/98/Me:
  %Windir%
- Windows NT/2000/XP:
  %Windir%\System32\drivers\etc
  
  Notes:
- The location of the hosts file may vary and some computers may not have this file. There may also be multiple copies of this file in different locations. If the file is not located in these folders, search your disk drives for the hosts file, and then complete the following steps for each instance found.
- %Windir% is a variable that refers to the Windows installation folder. By default, this is C:\Windows (Windows 95/98/Me/XP) or C:\Winnt (Windows NT/2000).
Double-click the hosts file.
If necessary, deselect the "Always use this program to open this program" check box.
Scroll through the list of programs and double-click Notepad.
When the file opens, delete all the entries added by the risk. (See the Technical Details section for a complete list of entries.)
Close Notepad and save your changes when prompted.

3. 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 Virus Definitions (LiveUpdate).
Downloading the definitions using the Intelligent Updater: The Intelligent Updater virus definitions are posted daily. 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 Virus Definitions (Intelligent Updater).

The latest Intelligent Updater virus definitions can be obtained here: Intelligent Updater virus definitions. For detailed instructions read the document: How to update virus definition files using the Intelligent Updater.

4. To scan for and delete the infected files

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.
Run a full system scan.
If any files are detected, click Delete.

Important: If you are unable to start your Symantec antivirus product or the product reports that it cannot delete a detected file, you may need to stop the risk from running in order to remove it. To do this, run the scan in Safe mode. For instructions, read the document, How to start the computer in Safe Mode. Once you have restarted in Safe mode, run the scan again.

After the files are deleted, restart the computer in Normal mode and proceed with the next section.

Warning messages may be displayed when the computer is restarted, since the threat may not be fully removed at this point. You can ignore these messages and click OK. These messages will not appear when the computer is restarted after the removal instructions have been fully completed. The messages displayed may be similar to the following:

Title: [FILE PATH]
Message body: Windows cannot find [FILE NAME]. Make sure you typed the name correctly, and then try again. To search for a file, click the Start button, and then click Search.

5. To delete the value from the registry
Important: 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 subkeys only. For instructions refer to the document: How to make a backup of the Windows registry.

Click Start > Run.
Type regedit
Click OK.

Note: If the registry editor fails to open the threat may have modified the registry to prevent access to the registry editor. Security Response has developed a tool to resolve this problem. Download and run this tool, and then continue with the removal.
Navigate to the subkey:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
In the right pane, delete the values:

"devsec"
"ms_anti_spyware" = "%Windir%\mwfirewall.exe"
Navigate to the subkey:

HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer
In the right pane, delete the values:

"sp0furl" "upurl" "sockport" "emsss" "emsrv" "lmnla" "veer" "mtxnm"
Navigate to the subkeys:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\RunOnce HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\RunOnce
In the right pane, delete the value:

"ms_anti_spyware" = "%Windir%\mwfirewall.exe"
Navigate to the subkeys:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\OLE HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Lsa HKEY_CURRENT_USER\Software\Microsoft\OLE HKEY_CURRENT_USER\System\CurrentControlSet\Control\Lsa
In the right pane, delete the value:

"WINRUN" = "svch0st.exe"
Navigate to the subkey:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon
In the right pane, reset the values to the original values if applicable:

"SFCDisable" = "0" "SFCScan" = "0"
Navigate to the subkeys:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies
In the right pane, reset the value to the original value if applicable:

"DisableRegistryTools" = "0"
Exit the Registry Editor.

Revision History:

December 3, 2005: Updated with link to removal tool.

Write-up by: Hatsuho Honda