W32/Mytob-FW

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.

Close the registry editor.

W32/Mytob-FW is a mass-mailing worm and backdoor Trojan that can be controlled
through the Internet Relay Chat (IRC) network.

W32/Mytob-FW 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.

When W32/Mytob-FW is installed it creates the file <System>\syst.exe.

The file syst.exe is detected as Troj/Monurl-Fam.

W32/Mytob-FW creates the following registry entries:

HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
Debugger
dbg32.exe

HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\RunServices
Debugger
dbg32.exe

W32/Mytob-FW sets the following registry entries, disabling the automatic
startup of other software:

HKLM\SYSTEM\CurrentControlSet\Services\SharedAccess
Start
4

Note: disabling autostart for the SharedAccess service deactivates the
Microsoft Internet Connection Firewall (ICF).

Emails sent by W32/Mytob-FW sends emails in the following format, with details
filled in to make the email look more authentic:

Subject line chosen from:

Your password has been updated
Your password has been successfully updated
You have successfully updated your password
Your new account password is approved
Your Account is Suspended
*DETECTED* Online User Violation
Your Account is Suspended For Security Reasons
Warning Message: Your services near to be closed.
Important Notification
Members Support
Security measures
Email Account Suspension
Notice of account limitation
<random characters>

Message text chosen from (the worm will insert the username and the email
domain of the addressee into the email):

'Dear user <UserName>,

You have successfully updated the password of your <domain> account.

If you did not authorize this change or if you need assistance with your
account, please contact <domain> customer service at:
Thank you for using <domain>!
The Support Team

+++ Attachment: No Virus (Clean)
+++ <domain> Antivirus - www.<domain>'

'Dear user <UserName>,

It has come to our attention that your <domain> User Profile ( x ) records are
out of date. For further details see the attached document.
Thank you for using <domain>!
The <domain> Support Team

+++ Attachment: No Virus (Clean)
+++ <domain> Antivirus - www.<domain>'

'Dear <domain> Member,

We have temporarily suspended your email account <UserEmailAddress>.

This might be due to either of the following reasons:

1. A recent change in your personal information (i.e. change of address).
2. Submiting invalid information during the initial sign up process.
3. An innability to accurately verify your selected option of subscription due
to an internal error within our processors.
See the details to reactivate your <domain> account.

Sincerely,The <domain> Support Team

+++ Attachment: No Virus (Clean)
+++ <domain> Antivirus - www.<domain>'

'Dear <domain> Member,

Your e-mail account was used to send a huge amount of unsolicited spam messages
during the recent week. If you could please take 5-10 minutes out of your
online experience and confirm the attached document so you will not run into
any future problems with the online service.
If you choose to ignore our request, you leave us no choice but to cancel your
membership.

Virtually yours,
The <domain> Support Team

+++ Attachment: No Virus found
+++ <domain> Antivirus - www.<domain>'

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

updated-password
email-password
new-password
password
approved-password
account-password
accepted-password
important-details
account-details
email-details
account-info
document
readme
account-report
<random characters>

The zip file will contain the worm with double extension. The first extension
will be one of DOC, HTM, TXT followed by spaces and the second extension is
EXE, SCR or PIF.

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