This detection is for a worm that exploits the MS08-067 vulnerability as the main vehicle of infection. It also uses other common technique for spreading as underlined in the Method of infeciton section. It also download and execute various files onto the affected system.
|
Minimum DAT
6875 (2012-10-24) Updated DAT6965 (2013-01-24) |
Minimum Engine
5400.1158 File Lengthvaries |
Description Added
2009-01-06 Description Modified2013-01-25 |
-------Updated on Jan 25, 2013 -----------------
Aliases –
Characteristics –
"W32/Conficker.worm.gen.a" is a worm that spreads across a network by exploiting vulnerability in the Windows Server service [Microsoft Security Bulletin MS08-067]. If the vulnerability is successfully exploited, it could allow remote code execution when file sharing is enabled. It may also spread via removable drive and weak administrator passwords.
W32/Conficker.worm.gen.a targets the Microsoft Windows operating system. It uses flaws in Windows software and dictionary attacks on administrator passwords to propagate using a botnet, and has been unusually difficult to counter because it get injected with windows server services.
W32/Conficker.worm.gen.a runs an HTTP server on a port between 1024 and 10000; the target shell code connects back to this HTTP server to download a copy of the virus in DLL form, which it then attaches to Services.exe and remotely execute copies of themselves through the ADMIN$ share on computers visible over NetBIOS.
W32/Conficker.worm.gen.a disables system security services in order to avoid detection and also tries to flood the network.
Upon execution, the Worm tries to connect the following URL/IP Address through remote port 53/137/http.
The following are the files dropped by the worm:
This Worm also attempts to create an autorun.inf file on the root of any accessible disk volumes:
The file "AutoRun.inf" is pointing to the malware binary executable. When the removable or networked drive is accessed from a machine supporting the Autorun feature, the malware is launched automatically.
The autorun.inf is configured to launch the Worm file via the following command syntax.
;
ÅA¯˜ölÜŠq¦…tÎKVWœý¸¤¬ ¬ AcTION ¬ = Open folder to view files
icon = %syStEmrOot%\sySTEM32\sHELL32.Dll ,4
;Pr×SoàDWWCfDnhTvVQyaã¾
; «GáÊ
; qTJ¥•r€ÕoÍgwDqçÚJûKEí´û
shelLExECUte =RuNdLl32.EXE .\RECYCLER\S-5-3-42-2819952290-8240758988-879315005-3665\jwgkvsq.vmx,ahaezedrn ;
zD¾pl¿›cà½ÂuDbËyF½ÚG ¬ ; f›yÊlÌÃèŠdGµBwAsUmF ¬
; »Ÿobz²q•GEìªiSøµväF˜Ø¤ò¼fîNŒDs±
useAuTopLAY = 1
; Fª†g•¿úoÖMÊc°¹tYcÈìkdQeæØnD§äâÙrˆe…C¿ùlÝ„ôC
‘±jHÙE¼€PšxEAb«¬µÞ˜ãñIzg›AÉdǸæÄ†•‘bçÇ
blGkNaAOAStfJarztHQsDTE = X
; Cnˆº´ðôãƒke´j÷gWÚ©ÖçJÇtþ¨iMUÒ‘çtáæVJd
; UNÜaBYùfsÊ c¢a’nGHP¯TpZ¢wo
; ûÀzñIhMÖùîVÛXeäõÖrGa§”Z“FySÝIIUìHk¸¡ÍE®fWˆÞLÅ
The following are the registry keys have been added to the system
The above registry entries ensures that the worm create a firewall rule for the TCP port 2105 and 6962 to bypass the normal authentication.
The following are the registry key values modified to the system.
The above registry confirms that the worm tries to hide itself from the user.
The above registry key values confirms that the worm tries to disable the following security services “Security Center, Automatic Updates, Error Reporting Service, Background Intelligent Transfer Service”
--Updated on December 29, 2011---
Aliases –
Upon execution, the worm first queries the following websites to get the public IP Address of the infected machines.
It broadcasts the following SNMP message on the network:
M-SEARCH * HTTP/1.1
HOST: 239.255.255.250:1900
ST: urn:schemas-upnp-org:device:InternetGatewayDevice:1
MAN: "ssdp:discover"
MX: 3
(router, modem, switch, etc...) with UPNP enabled and the urn:schemas-upnp-org:device:InternetGatewayDevice:1 service, will respond to the SNMP message.
The worm performs further malicious activities based on response from the above request.
The following services are disabled or fail to run:
It also disables any process that has a module name containing any of the following strings from sending network traffic or data.
virus
spyware
malware
rootkit
defender
microsoft
symantec
norton
mcafee
trendmicro
sophos
panda
etrust
networkassociates
computerassociates
The following registry keys have been added
The following registry values have been added
-------
--Updated on November 2, 2011---
Aliases
The following value has been modified.
The above mentioned registry entries confirms that the Worm prevents the compromised user to view the hidden files and folders in the system.
In order to exploit the vulnerability, the worm attempts to connect to the Administrator account on the remote machine. The worm uses the following passwords to brute force the account:
99999999
9999999
999999
99999
88888888
8888888
888888
88888
77777777
7777777
777777
77777
66666666
6666666
666666
66666
55555555
5555555
555555
55555
44444444
4444444
444444
44444
33333333
3333333
333333
33333
22222222
2222222
222222
22222
11111111
1111111
111111
11111
0
0
0
987654321
987654321
87654321
7654321
654321
54321
zzzzz
xxxxx
qqqqq
aaaaa
intranet
controller
killer
games
private
market
coffee
cookie
forever
freedom
student
account
academia
files
windows
monitor
unknown
anything
letitbe
letmein
domain
access
money
campus
explorer
exchange
customer
cluster
nobody
codeword
codename
changeme
desktop
security
secure
public
system
shadow
office
supervisor
superuser
share
super
secret
server
computer
owner
backup
database
lotus
oracle
business
manager
temporary
ihavenopass
nothing
nopassword
nopass
Internet
internet
example
sample
love123
boss123
work123
home123
mypc123
temp123
test123
qwe123
abc123
pw123
root123
pass123
pass12
pass1
admin123
admin12
admin1
password123
password12
password1
default
foobar
foofoo
temptemp
testtest
rootroot
adminadmin
mypassword
mypass
Login
login
Password
password
passwd
zxcvbn
zxcvb
zxccxz
zxcxz
qazwsxedc
qazwsx
q1w2e3
qweasdzxc
asdfgh
asdzxc
asddsa
asdsa
qweasd
qwerty
qweewq
qwewq
nimda
administrator
Admin
admin
a1b2c3
1q2w3e
1234qwer
1234abcd
123asd
123qwe
123abc
123321
12321
123123
1234567890
123456789
12345678
1234567
123456
12345
-- Updated October 19, 2011---
Aliases
When executed the Worm it tries to connects to the site max[Removed]nd.com through a remote port 80.
The following registry key has been added to the system.
The following registry value has been added.
A mutex is created to ensure only one instance of the worm is running at a time.
----------------------------------------------------------------------------
-- Update May 19, 2010 --File Information -
This "W32/Conficker.worm.gen.a" spreads via Local networks and removable media and it is packed with packer.
Upon execution, the worm copies itself into the following locations:
And it attempts to create an autorun.inf file on the root any accessible disk volume
Also it changes the following registry values in attempt to change the windows explorer view settings
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Advanced\Folder\Hidden\SHOWALL
CheckedValue = 0
In order to exploit the vulnerability, the worm attempts to connect to the Administrator account on the remote machine. The worm uses the following passwords to brute force the account:
Also, it connects to the following ip addresses 239.[removed].250 using remote port: 1900
------------------------------
When executed, the worm copies itself using a random name to the %Sysdir% folder.
(Where %Sysdir% is the Windows system folder; e.g. C:\Windows\System32 and %RemovableDrive% = Removable drive inserted into the system)
New variants have been observed dropping copies of themselfs aslo into:
Where [random] is a 4 to 8 long letters only random name.
On NTFS filesystems the dropped files do have often modified access permissions. Access is completely removed on the file for all users and groups. This is done to make detection and cleaning more difficult.
It modifies the following registry key to create a randomly-named service on the affected syetem:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\{random}\Parameters\"ServiceDll" = "Path to worm"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\{random}\"ImagePath" = %SystemRoot%\system32\svchost.exe -k netsvcs
Several variants do remove access to the above registry key by changing the key ACLs. This also in an attempt to make detection and removal of the serive key more difficult. The service name is generated dinamically by associating words from an hardcoded list:
It will inject intelf into various running processes. Different variant have been observer injecting into one or more of:
Attempts connections to one or more of the following websites to obtain the public ip address of the affected computer.
Attempts to download a malware file from the remote website
hxxp://trafficconverter.biz/[Removed]antispyware/[Removed].exe
New variants are connecting to various other hosts.
Starts a HTTP server on a random port on the infected machine to host a copy of the worm.
Continuously scans the subnet of the infected host for vulnerable machines and executes the exploit. If the exploit is successful, the remote computer will then connect back to the http server and download a copy of the worm. The http connection is performed on a random port and the file transferred will have an extension of
Later variants of w32/Conficker.worm do attempt to connect to remote hosts using the local credentials and a list of username retrieved from the target system and a long list of hardcoded passwords. In doing so it may lock down domain accounts where the policy is set to allow only a limited number of wrong passwords.
On succesfully exploited remote systems the worm drops a copy of itself in the $sysdir% folder and creates a scheduled tasks to execute it. It may olso create a copy in the remote "Recycle Bin" folder and an Autorun.inf file.
Using these techniques the worm may replicate on to non vulnerable systems or reinfect previously infected systems after they have been cleaned.
The worm hooks system APIs to prevent access to security websites. A list of some of the locked domains is:
Some security services may also be disabled by the infection.
-------Updated on Jan 25, 2013 ----------------- --Updated on December 29, 2011--- This worm exploits the MS08-067 Microsoft Windows Server Service vulnerability in order to propagate. Machines should be patched and rebooted to protect against this worm re-infecting the system after cleaning. It also spread by brute forcing remote systems password and installing scheduled tasks and/or autorun.inf files on the victim.
This worm may be spread by its intended method of infected removable drives. Alternatively this may be installed by visiting a malicious web page (either by clicking on a link), or by the website hosting a scripted exploit which installs the worm onto the user's system with no user interaction.
All Users:
Use current engine and DAT files for detection and removal.
Modifications made to the system Registry and/or INI files for the purposes of hooking system startup, will be successfully removed if cleaning with the recommended engine and DAT combination (or higher).