W32/Mytob-CX

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.

Close the registry editor.

W32/Mytob-CX is a mass-mailing worm and IRC backdoor Trojan for the Windows platform.

W32/Mytob-CX 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.

Email sent by W32/Mytob-CX have the following properties:

Subject line chosen from:

'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'

Message text chosen from:

'Dear <company name> Member,

We have temporarily suspended your email account <Email address>.

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 <company name> account.

Sincerely,The <company name> Support Team

+++ Attachment: No Virus (Clean)
+++ <company name> Antivirus - <web address>'

'Dear <company name> 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 <company name> Support Team

+++ Attachment: No Virus found
+++ <company name> Antivirus - <web address>'

'Dear user <username>,

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

If you did not authorize this change or if you need assistance with your account, please contact <company name> customer service at: <email address>

Thank you for using <company name>!The <company name> Support Team

+++ Attachment: No Virus (Clean)
+++ <company name> Antivirus - <web address>'

'Dear user <username>,

It has come to our attention that your <company name> User Profile ( x ) records are out of date. For further details see the attached document.

Thank you for using <company name>!
The <company name> Support Team

+++ Attachment: No Virus (Clean)
+++ <company name> Antivirus - <web address>'

The attached file consists of any of the following base names followed by the extension ZIP:

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

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-CX harvests email addresses from files on the infected computer and from the Windows address book. The worm will also terminate security-related processes and Windows applications.

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

HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\RunServices
WINDOWS SYSTEM
skybot.exe

HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
WINDOWS SYSTEM
skybot.exe

W32/Mytob-CX also disables the Windows XP firewall by changing the following default registry entry:

from:
HKLM\SYSTEM\CurrentControlSet\Services\SharedAccess
Start
3

to:
HKLM\SYSTEM\CurrentControlSet\Services\SharedAccess
Start
4

W32/Mytob-CX also includes functionality to silently download, install and run new software.

Registry changes may also be made under the following registry entry:

HKCU\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Zones\3\Current Level

W32/Mytob-CX modifies the HOSTS file, changing the URL-to-IP mappings for selected websites, therefore preventing normal access to these sites. The new HOSTS file will typically contain the following:

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 kaspersky-labs.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 pandasoftware.com
127.0.0.1 www.pandasoftware.com
127.0.0.1 www.trendmicro.com
127.0.0.1 www.grisoft.com
127.0.0.1 www.microsoft.com
127.0.0.1 microsoft.com
127.0.0.1 www.virustotal.com
127.0.0.1 virustotal.com
127.0.0.1 www.amazon.com
127.0.0.1 www.amazon.co.uk
127.0.0.1 www.amazon.ca
127.0.0.1 www.amazon.fr
127.0.0.1 www.paypal.com
127.0.0.1 paypal.com
127.0.0.1 moneybookers.com
127.0.0.1 www.moneybookers.com
127.0.0.1 www.ebay.com
127.0.0.1 ebay.com