W32/Mytob-DC

Please follow the instructions for removing worms.

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.

Sophos's anti-virus products include Genotype ™ detection technology, which can proactively protect against new threats without requiring an update. Sophos customers have been protected against W32/Mytob-DC (detected as W32/Mytob-Fam) since version 3.94.

W32/Mytob-DC is a mass-mailing worm with backdoor functionality for the Windows platform.

W32/Mytob-DC runs continuously in the background, providing a backdoor server which allows a remote intruder to gain access and control over the computer via IRC channels.

W32/Mytob-DC spreads by exploiting computers vulnerable to the LSASS (MS04-011) exploit and by sending itself as an email attachment. Emails sent by the worm have the following characteristics:

Subject:

Error
Status
Server Report
Mail Transaction Failed
Mail Delivery System
hello
Good day

Body:

Mail transaction failed. Partial message is available.

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

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

The original message was included as an attachment.

Here are your banks documents.

Attachment filenames:

body
message
test
data
file
text
readme
document

When first run W32/Mytob-DC copies itself to:

\mypic003.scr
\mypic004.scr
\mypic005.scr
<Windows system folder>\taskgmrr.exe

and creates the file \mngr32.exe.

The file mngr32.exe is detected as W32/Mytob-D.

The following registry entries are created to run taskgmrr.exe on startup:

HKCU\Software\Microsoft\Windows\CurrentVersion\Run
WINTASK32
taskgmrr.exe

HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
WINTASK32
taskgmrr.exe

HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\RunServices
WINTASK32
taskgmrr.exe

Registry entries are set as follows:

HKCU\SYSTEM\CurrentControlSet\Control\Lsa
WINTASK32
taskgmrr.exe

HKLM\SYSTEM\CurrentControlSet\Control\Lsa
WINTASK32
taskgmrr.exe

HKCU\Software\Microsoft\OLE
WINTASK32
taskgmrr.exe

HKLM\SOFTWARE\Microsoft\Ole
WINTASK32
taskgmrr.exe

The following patches for the operating system vulnerabilities exploited by W32/Mytob-DC can be obtained from the Microsoft website:

MS04-011