W32/Mytob-CA

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

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

HKLM\Software\Microsoft\Windows\CurrentVersion\Run
Windows Shell
"shell.exe"

HKLM\Software\Microsoft\Windows\CurrentVersion\RunServices
Windows Shell
"shell.exe"

W32/Mytob-CA also appends the following to the HOSTS file to deny access to security-related websites:

avp.com
ca.com
customer.symantec.com
dispatch.mcafee.com
download.mcafee.com
f-secure.com
kaspersky-labs.com
kaspersky.com
liveupdate.symantec.com
liveupdate.symantecliveupdate.com
mast.mcafee.com
mcafee.com
my-etrust.com
nai.com
networkassociates.com
rads.mcafee.com
secure.nai.com
securityresponse.symantec.com
sophos.com
symantec.com
trendmicro.com
update.symantec.com
updates.symantec.com
viruslist.com
viruslist.com
www.avp.com
www.ca.com
www.grisoft.com
www.kaspersky.com
www.mcafee.com
www.microsoft.com
www.my-etrust.com
www.nai.com
www.networkassociates.com
www.sophos.com
www.symantec.com
www.trendmicro.com
www.viruslist.com

W32/Mytob-CA is capable of spreading through email. Email sent by W32/Mytob-CA has the following properties:

Subject line:

Error
hello
Here is your documents.
Mail Delivery System
Mail Transaction Failed
Re: Thank you for delivery
something for you
Status

Message text:

'Mail transaction failed. Partial message is available.'
'Mail transaction failed. Partial message is available.'
'The message cannot be represented in 7-bit ASCII encoding 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 message contains Unicode characters and has been sent as a binary attachment.'
'The message contains Unicode characters and has been sent as a binary attachment.'
'The original message was included as an attachment.'
'The original message was included as an attachment.'

The attached file consists of a base name followed by the extentions PIF, SCR, EXE or ZIP. The base names will be one of the following:

DOCUMENT
README
ATTACHMENT
creditcard
LETTER
PayPal

W32/Mytob-CA 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:

.gov
.mil
accoun
acketst
admin
anyone
arin.
avp
berkeley
borlan
bsd
bsd
bugs
ca
certific
contact
example
feste
fido
foo.
fsf.
gnu
gold-certs
google
google
gov.
help
iana
ibm.com
icrosof
icrosoft
ietf
info
inpris
isc.o
isi.e
kernel
linux
linux
listserv
math
me
mit.e
mozilla
mydomai
no
nobody
nodomai
noone
not
nothing
ntivi
page
panda
pgp
postmaster
privacy
rating
rfc-ed
ripe.
root
ruslis
samples
secur
sendmail
service
site
soft
somebody
someone
sopho
submit
support
syma
tanford.e
the.bat
unix
unix
usenet
utgers.ed
webmaster
you
your

W32/Mytob-CA may produce the file helllogger.txt which is a harmless text file used to log the activity of the user.