W32/Mytob-G

Please follow the instructions for removing worms.

Replace the Hosts file from a backup or edit it in Notepad to remove the changes that the worm has made.

You will also need to edit the following registry entries, if they are present. Please read the warning about editing the registry.

At the taskbar, click Start|Run. Type 'Regedit' and press Return. The registry editor opens.

Before you edit the registry, you should make a backup. On the 'Registry' menu, click 'Export Registry File'. In the 'Export range' panel, click 'All', then save your registry as Backup.

Locate the HKEY_LOCAL_MACHINE entries:

HKLM\Software\Microsoft\Windows\CurrentVersion\Run

HKLM\Software\Microsoft\Windows\CurrentVersion\RunServices

and remove any reference to any file you deleted.

Each user has a registry area named HKEY_USERS\[code number indicating user]\. For each user locate the entry:

HKU\[code number]\Software\Microsoft\Windows\
CurrentVersion\Run\

and remove any reference to any file you deleted.

Close the registry editor.

Check the following items

• The HKLM\SYSTEM\CurrentControlSet\Control\Lsa\restrictanonymous = "1" setting does not allow enumeration of SAM accounts and names. The default is "0". It can be changed in Local Security Policy. See Microsoft article 246261 for details.
• Check your administrator passwords and review network security.

W32/Mytob-G is a mass-mailing worm and backdoor Trojan that targets
users of Internet Relay Chat programs. W32/Mytob-G is a mass-mailing worm and backdoor Trojan that targets users of Internet Relay Chat programs.

When first run W32/Mytob-G copies itself to the Windows system folder as tagmr.exe and creates the following registry entries:

HKCU\Software\Microsoft\OLE
Windows Tagmsnger
tagmr.exe

HKCU\SYSTEM\CurrentControlSet\Control\Lsa
Windows Tagmsnger
tagmr.exe

HKCU\Software\Microsoft\Windows\CurrentVersion\Run
Windows Tagmsnger
tagmr.exe

HKLM\SOFTWARE\Microsoft\Ole
Windows Tagmsnger
tagmr.exe

HKLM\SYSTEM\CurrentControlSet\Control\Lsa
Windows Tagmsnger
tagmr.exe

HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
Windows Tagmsnger
tagmr.exe

HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\RunServices
Windows Tagmsnger
tagmr.exe

W32/Mytob-G copies itself to the root folder as:

funny_pic.scr
my_photo2005.scr
see_this!!.scr

and creates the helper file hellmsn.exe (detected by Sophos as W32/Mytob-D) in the same location.

W32/Mytob-G also appends the following to the HOSTS file to deny access to security related websites:

127.0.0.1 www.symantec.com
127.0.0.1 securityresponse.symantec.com
127.0.0.1 symantec.com
127.0.0.1 www.sophos.com
127.0.0.1 sophos.com
127.0.0.1 www.mcafee.com
127.0.0.1 mcafee.com
127.0.0.1 liveupdate.symantecliveupdate.com
127.0.0.1 www.viruslist.com
127.0.0.1 viruslist.com
127.0.0.1 viruslist.com
127.0.0.1 f-secure.com
127.0.0.1 www.f-secure.com
127.0.0.1 kaspersky.com
127.0.0.1 www.avp.com
127.0.0.1 www.kaspersky.com
127.0.0.1 avp.com
127.0.0.1 www.networkassociates.com
127.0.0.1 networkassociates.com
127.0.0.1 www.ca.com
127.0.0.1 ca.com
127.0.0.1 mast.mcafee.com
127.0.0.1 my-etrust.com
127.0.0.1 www.my-etrust.com
127.0.0.1 download.mcafee.com
127.0.0.1 dispatch.mcafee.com
127.0.0.1 secure.nai.com
127.0.0.1 nai.com
127.0.0.1 www.nai.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 liveupdate.symantec.com
127.0.0.1 customer.symantec.com
127.0.0.1 rads.mcafee.com
127.0.0.1 trendmicro.com
127.0.0.1 www.microsoft.com
127.0.0.1 www.trendmicro.com