Zotob.C is a new variant of Zotob. It spreads using a vulnerability in Windows Plug and Play service (MS05-039) and ASN.1 (MS04-007). This variant also has Mydoom e-mail spreading routine.
The worm is a packed PE executable file 31744 bytes long.
Installation to system
When run, the worm copies under %SYSTEM% directory using the name 'per.exe' and creates a named mutex 'B-O-T-Z-O-R' for making sure that only one copy of the worm is run at the same time.
Then it adds the following registry entries to ensure that it is started when a user logs on or the system is restarted:
The worm can spread by sending its infected attachment to e-mail addresses found on an infected computer. E-mail addresses are harvested from Windows address book and from files with the following extensions:
txt
htm
sht
jsp
cgi
xml
php
asp
dbx
tbb
adb
wab
pl
The worm avoids sending e-mails to e-mail addresses that contain any of the following substrings:
avp
syma
icrosof
msn.
hotmail
panda
sopho
borlan
inpris
example
mydomai
nodomai
ruslis
.gov
gov.
.mil
foo.
berkeley
unix
math
mit.e
fsf.
ibm.com
google
kernel
linux
fido
usenet
iana
ietf
rfc-ed
sendmail
arin.
ripe.
isi.e
isc.o
secur
acketst
tanford.e
utgers.ed
mozilla
be_loyal:
root
info
samples
postmaster
webmaster
noone
nobody
nothing
anyone
someone
your
bugs
rating
site
contact
soft
somebody
privacy
service
help
submit
feste
gold-certs
the.bat
page
admin
icrosoft
support
ntivi
unix
linux
listserv
certific
google
accoun
fcnz
secur
abuse
The e-mail message is composed from randomly chose subject line, body text and additional parts. The worm has a selection of attachment names that it uses for its attachment. The subject of infected e-mails are selected from the following variants:
Warning!!
**Warning**
Hello
Confirmed...
Important!
Body of the text is selected from the following list:
looooool
We found a photo of you in ...
That's your photo!!?
hey!!
0K here is it!
The attachment name is composed using predefined keywords. The keywords set is:
photo
your_photo
image
picture
sample
loool
webcam_photo
And extension keywords set are:
bat
cmd
exe
scr
pif
Spreading using exploits
The worm scans for systems vulnerable to Microsoft Windows Plug and Play service (MS05-039) and ASN.1 vulnerability (MS04-007) through TCP/445.
It creates 200 threads that connect to random IP addresses within the B-class (255.255.0.0) network of the infected system. First it tests connection to port 445 and if successful, it tries to exploit the PnP vulnerability. If the attack is successful, a shell (cmd.exe) is started and FTP script is transferred and executed on the remote machine. This script then downloads and executes the worm's file from the attacking machine. Please see the details of this attack from Zotob.A description:
http://www.f-secure.com/v-descs/zotob_a.shtml
If the PnP attack fails, the worm tries to exploit ASN.1 vulnerability (MS04-007). The attack is very similair to PnP attack - an FTP script is executed on a remote host and the built-in FTP server is then used to transfer the worm's file to exploited system. ASN.1 exploit is reported to work on (unpatched) Windows 2000 SP 2-4 and Windows XP SP 0-1.
Please see the following pages for detailed information on the vulnerabilities:
The worm tries to connect to IRC channel at predefined address. The attacker who knows channel password can instruct the bot to execute the following actions:
Disconnect/reconnect from the IRC channel
Request system information
Download and execute files
Remove worm from the system
Manipulate system security settings
Additional details
Zotob.C modifies system hosts file in order to disable access to certain sites. Following hostnames are redirected to localhost IP address (127.0.0.1):
avp.com
ca.com
customer.symantec.com
dispatch.mcafee.com
download.mcafee.com
ebay.com
f-secure.com
kaspersky.com
kaspersky-labs.com
liveupdate.symantec.com
liveupdate.symantecliveupdate.com
mast.mcafee.com
mcafee.com
microsoft.com
moneybookers.com
my-etrust.com
nai.com
networkassociates.com
pandasoftware.com
paypal.com
rads.mcafee.com
secure.nai.com
securityresponse.symantec.com
sophos.com
symantec.com
trendmicro.com
updates.symantec.com
update.symantec.com
us.mcafee.com
viruslist.com
virustotal.com
www.amazon.com
www.avp.com
www.ca.com
www.ebay.com
www.f-secure.com
www.grisoft.com
www.kaspersky.com
www.mcafee.com
www.microsoft.com
www.moneybookers.com
www.my-etrust.com
www.nai.com
www.networkassociates.com
www.pandasoftware.com
www.paypal.com
www.sophos.com
www.symantec.com
www.trendmicro.com
www.virustotal.com
The worm also writes the following text to hosts file:
Botzor2 pnp+asn+mail spread. Greetz to good friend Coder. Based On HellBot3 f-secure,sophos ok wait bitchs!!!
