W32/Mytob-FH

Category: Viruses and Spyware
Type: Win32 worm
Prevalence: Several Reports

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

W32/Mytob-FH 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.

Emails sent by the worm have characteristics from the following:

Subject line:
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 - a formatted version of one of the following:
Dear user <recipient's username>,

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

If you did not authorize this change or if you need assistance with your account, please contact <recipient's domain> customer service at: <spoofed sender address>

Thank you for using <recipient's domain>!
The <recipient's domain> Support Team <BR>

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

Dear user <recipient's username>,

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 User Profile ( x ) records are out of date.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

Thank you for using <recipient's domain>!
The <recipient's domain> Support Team

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

Dear <recipient's username> Member,

We have temporarily suspended your email account <recipient's domain>.

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 <recipient's domain> account.

Sincerely,The <recipient's domain> Support Team

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

Dear <recipient's 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 <recipient's domain> Support Team

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

Attachment name:
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

First extension (of attachment or of file inside zip):
doc
htm
txt

Second extension (of attachment or of file inside zip):
pif
scr
exe
cmd
bat

If the attachment is a zip file it will have the same base name as the double-extension file inside. W32/Mytob-FH is a mass-mailing worm and IRC backdoor Trojan for the Windows platform.

W32/Mytob-FH 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.

Emails sent by the worm have characteristics from the following:

Subject line:
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 - a formatted version of one of the following:
Dear user <recipient's username>,

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

If you did not authorize this change or if you need assistance with your account, please contact <recipient's domain> customer service at: <spoofed sender address>

Thank you for using <recipient's domain>!
The <recipient's domain> Support Team <BR>

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

Dear user <recipient's username>,

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

Thank you for using <recipient's domain>!
The <recipient's domain> Support Team

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

Dear <recipient's username> Member,

We have temporarily suspended your email account <recipient's domain>.

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 <recipient's domain> account.

Sincerely,The <recipient's domain> Support Team

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

Dear <recipient's 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 <recipient's domain> Support Team

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

Attachment name:
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

First extension (of attachment or of file inside zip):
doc
htm
txt

Second extension (of attachment or of file inside zip):
pif
scr
exe
cmd
bat

If the attachment is a zip file it will have the same base name as the double-extension file inside.

Example attachment names include document.txt.pif and information.doc.cmd, usually with a large number of spaces between the extensions.

The following registry entries are created:

HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
NAMEDPIPE SYSTEM
\namedpipe.exe

HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\RunServices
NAMEDPIPE SYSTEM
\namedpipe.exe

W32/Mytob-FH 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).

W32/Mytob-FH 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

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