W32/Mytob-H

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-H is a mass-mailing worm and backdoor Trojan that targets users of Internet Relay Chat programs.

W32/Mytob-H is capable of spreading through various operating system vulnerabilities such as LSASS (MS04-011). W32/Mytob-H is a mass-mailing worm and backdoor Trojan that targets users of Internet Relay Chat programs.

W32/Mytob-H is capable of spreading through various operating system vulnerabilities such as LSASS (MS04-011).

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

HKCU\Software\Microsoft\OLE
WINTASK
taskgmr.exe

HKCU\System\CurrentControlSet\Control\Lsa
WINTASK
taskgmr.exe

HKCU\Software\Microsoft\Windows\CurrentVersion\Run
WINTASK
taskgmr.exe

HKLM\Software\Microsoft\Windows\CurrentVersion\Run
WINTASK
taskgmr.exe

HKLM\Software\Microsoft\Windows\CurrentVersion\RunServices
WINTASK
taskgmr.exe

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

funny pic.scr
eminem vs 2pac.scr
photo album.scr

W32/Mytob-H 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

Emails sent by W32/Mytob-H have the following characteristics:

Subject line chosen from:

Error
Status
Server Report
Mail Transaction Failed
Mail Delivery System
hello
thanks!
read it immediately

Message text chosen from:

Here are your banks documents.

The original message was included as an attachment.

The message cannot be represented in 7-bit ASCII encoding and has been sent as a binary attachment.

The message contains Unicode characters and has been sent as a binary attachment.

Mail transaction failed. Partial message is available.

The message cannot be represented in 7-bit ASCII encoding and has been sent as a binary attachment.

The attached file consists of a base name followed by the extentions BAT, CMD, PIF, SCR, EXE or ZIP. The worm may optionally create double extensions where the first extension is DOC, TXT or HTM and the final extension is PIF, SCR, EXE or ZIP.

W32/Mytob-H harvests email addresses from files on the infected computer and from the Windows address book.