W32/Mytob-CU

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

W32/Mytob-CU is capable of spreading through email and through various operating system vulnerabilities such as LSASS (MS04-011). W32/Mytob-CU is a mass-mailing worm and backdoor Trojan that can be controlled through the Internet Relay Chat (IRC) network.

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

HKLM\Software\Microsoft\Windows\CurrentVersion\Run
WINDOWS SYSTEM
"xxx.exe"

HKLM\Software\Microsoft\Windows\CurrentVersion\RunServices
WINDOWS SYSTEM
"xxx.exe"

W32/Mytob-CU 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

W32/Mytob-CU is capable of spreading through email and through various operating system vulnerabilities such as LSASS (MS04-011). Email sent by W32/Mytob-CU has the following properties:

Subject line:

Notice: **Last Warning**
*DETECTED* Online User Violation
Your Email Account is Suspended For Security Reasons
Account Alert
Important Notification
*WARNING* Your Email Account Will Be Closed
Security measures
Email Account Suspension
Notice of account limitation

Message text:

Once you have completed the form in the attached file , your account records will not be interrupted and will continue as normal.
The original message has been included as an attachment.
We regret to inform you that your account has been suspended due to the violation of our site policy, more info is attached.
We attached some important information regarding your account.
Please read the attached document and follow it's instructions.

The attached file consists of a base name followed by the extensions 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. The base filenames are randomly chosen from:

email-info
email-doc
information
account-details
document
instructions
info-texg
information

W32/Mytob-CU harvests email addresses from files on the infected computer and from the Windows address book. The worm avoids sending email to addresses that contain the following:

michael
george
andrew
robert
brenda
claudia
icrosof
hotmail
borlan
inpris
example
mydomai
nodomai
ruslis
berkeley
ibm.com
google
kernel
usenet
rfc-ed
sendmail
acketst
tanford.e
utgers.ed
mozilla
be_loyal:
samples
postmaster
webmaster
nobody
nothing
anyone
someone
rating
contact
somebody
privacy
service
submit
gold-certs
the.bat
icrosoft
support
listserv
certific
google
accoun
administrator
service
register