WORM_CRIDEX.AJ
Worm:Win32/Cridex.E (Microsoft), PWS-Zbot.gen.aow (McAfee)
Windows 2000, Windows XP, Windows Server 2003
Threat Type: Worm
Destructiveness: No
Encrypted: Yes
In the wild: Yes
OVERVIEW
This worm arrives via removable drives. It arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.
It drops an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system.
It executes commands from a remote malicious user, effectively compromising the affected system. However, as of this writing, the said sites are inaccessible.
It deletes the initially executed copy of itself.
TECHNICAL DETAILS
Arrival Details
This worm arrives via removable drives.
It arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.
Installation
This worm drops the following copies of itself into the affected system and executes them:
- %User Profile%\Application Data\KB{random number}.exe
(Note: %User Profile% is the current user's profile folder, which is usually C:\Windows\Profiles\{user name} on Windows 98 and ME, C:\WINNT\Profiles\{user name} on Windows NT, and C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003.)
It creates the following folders:
- %User Profile%\Application Data\{random folder name}
(Note: %User Profile% is the current user's profile folder, which is usually C:\Windows\Profiles\{user name} on Windows 98 and ME, C:\WINNT\Profiles\{user name} on Windows NT, and C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003.)
It adds the following mutexes to ensure that only one of its copies runs at any one time:
- Local\XME{8 random characters}
- Local\XMI{8 random characters}
- Local\XMM{8 random characters}
- Local\XMF{8 random characters}
- Local\XMS{8 random characters}
- Local\XMR{8 random characters}
It injects codes into the following process(es):
- explorer.exe
Autostart Technique
This worm adds the following registry entries to enable its automatic execution at every system startup:
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
KB{random number}.exe = "%User Profile%\Application Data\KB{random number}.exe"
Other System Modifications
This worm adds the following registry keys:
HKEY_CURRENT_USER\Software\Microsoft\
Windows NT\S{8 random characters}
HKEY_CURRENT_USER\Software\Microsoft\
Windows NT\C{8 random characters}
It adds the following registry entries:
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings
GlobalUserOffline = "0"
Propagation
This worm creates the following folders in all removable drives:
- {drive letter}:\{random folder}
It drops the following copy(ies) of itself in all removable drives:
- {drive letter}:\{random folder}\{random file name}.exe
It drops an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system.
The said .INF file contains the following strings:
[autorun]
open={random folder}\{random file name}.exe
shell\Open\Command={random folder}\{random file name}.exe
shell\Open\Default=1
shell\Explore\Command={random folder}\{random file name}.exe
shell\Autoplay\command={random folder}\{random file name}.exe
Backdoor Routine
This worm executes the following commands from a remote malicious user:
- Monitor browser cookies
- Download and execute arbitrary files
- Upload stolen information
- Download configuration files
It connects to the following URL(s) to send and receive commands from a remote malicious user:
- http://{BLOCKED}8.{BLOCKED}0.0.138:8080/LvI/xCA/GoZZkCAAAA/Noy6SAAAA/
- http://{BLOCKED}1.{BLOCKED}5.83.189:8080/LvI/xCA/GoZZkCAAAA/Noy6SAAAA/
- http://{BLOCKED}3.{BLOCKED}7.147.52:8080/LvI/xCA/GoZZkCAAAA/Noy6SAAAA/
- http://{BLOCKED}7.{BLOCKED}2.144.115:8080/LvI/xCA/GoZZkCAAAA/Noy6SAAAA/
- http://{BLOCKED}1.{BLOCKED}8.5.140:8080/LvI/xCA/GoZZkCAAAA/Noy6SAAAA/
- http://{BLOCKED}0.{BLOCKED}6.23.100:8080/LvI/xCA/GoZZkCAAAA/Noy6SAAAA/
- http://{BLOCKED}1.{BLOCKED}.235.35:8080/LvI/xCA/GoZZkCAAAA/Noy6SAAAA/
- http://{BLOCKED}9.{BLOCKED}0.221.6:8080/LvI/xCA/GoZZkCAAAA/Noy6SAAAA/
- http://{BLOCKED}8.{BLOCKED}8.2.214:8080/LvI/xCA/GoZZkCAAAA/Noy6SAAAA/
- http://{BLOCKED}0.{BLOCKED}9.13.84:8080/LvI/xCA/GoZZkCAAAA/Noy6SAAAA/
- http://{BLOCKED}1.{BLOCKED}1.168.98:8080/LvI/xCA/GoZZkCAAAA/Noy6SAAAA/
- http://{BLOCKED}9.{BLOCKED}5.134.110:8080/LvI/xCA/GoZZkCAAAA/Noy6SAAAA/
- http://{BLOCKED}3.{BLOCKED}8.208.55:8080/LvI/xCA/GoZZkCAAAA/Noy6SAAAA/
- http://{BLOCKED}3.{BLOCKED}9.61.59:8080/LvI/xCA/GoZZkCAAAA/Noy6SAAAA/
- http://{BLOCKED}5.{BLOCKED}2.167.193:8080/mx/5/A/in/
- http://{BLOCKED}8.{BLOCKED}0.0.138:8080/mx/5/A/in/
- http://{BLOCKED}2.{BLOCKED}0.101.32:8080/mx/5/A/in/
- http://{BLOCKED}8.{BLOCKED}0.22.72:8080/mx/5/A/in/
- http://{BLOCKED}3.{BLOCKED}7.147.52:8080/mx/5/A/in/
- http://{BLOCKED}1.{BLOCKED}8.5.140:8080/mx/5/A/in/
- http://{BLOCKED}0.{BLOCKED}6.23.100:8080/mx/5/A/in/
- http://{BLOCKED}8.{BLOCKED}8.2.214:8080/mx/5/A/in/
- http://{BLOCKED}1.{BLOCKED}1.168.98:8080/mx/5/A/in/
- http://{BLOCKED}0.{BLOCKED}9.13.84:8080/mx/5/A/in/
- http://{BLOCKED}9.{BLOCKED}5.134.110:8080/mx/5/A/in/
- http://{BLOCKED}3.{BLOCKED}8.208.55:8080/mx/5/A/in/
However, as of this writing, the said sites are inaccessible.
Information Theft
This worm monitors the Internet Explorer (IE) activities of the affected system, specifically the address bar. It recreates a legitimate website with a spoofed login page if a user visits banking sites with the following strings in the address bar and/or title bar:
- \.com/k1/
- /ach/
- /authentication/zbf/k/
- /bb/logon/
- chase\.com
- /cashman/
- /cashplus/
- /clkccm/
- /cmmain\.cfm
- /cmserver/
- /cmwire
- achredirect\.aspx
- cbonline
- /ebc_ebc1961/
- /ibs\.
- /ibws/
- /icm/
- /icm2/
- /inets/
- /livewire/
- /loginolb/loginolb
- /netbnx/
- /olbb/
- /phcp
- /sbuser/
- /smallbiz/
- /wcmpw/
- /webcm/
- /wire/
- /wires/
- 2checkout\.com
- ablv\.com
- access\.jpmorgan\.com
- access\.usbank\.com
- accessbankplc\.com
- accountoverview\.aspx
- accurint\.com
- achieveaccess\.citizensbank\.com
- achpayment
- achweb\.unionbank\.com
- achworks\.com
- alltimetreasury\.pacificcapitalbank\.com
- alphabank\.com
- amegybank\.com/
- anb\.portalvault\.com
- atbonlinebusiness\.com
- auth\.umb\.com
- authmaster\.nationalcity\.com
- baltikums\.com
- baltikums\.eu
- banesco\.com\.pa
- bankbyweb
- bankfirst\.com
- banking\.calbanktrust\.com
- banking\.firsttennessee\.biz
- accurint\.com
- plainscapital\.gfxwebwire\.com
- sterlingpayment\.com
- rbsm\.com
- business\.swedbank\.lv
- secure\.accesshorizon\.com
- myonline\.bankbv\.com
- cencorpcu\.com/
- banknet\.lv
- bankofbermuda\.com
- bankofcyprus\.com
- bankonline\.sboff\.com
- bankonline\.umpquabank\.com
- bbo\.1stsource\.com
- bib\.lv
- billauth
- billmenu
- bizcurrency\.com
- blilk
- bmo\.com/
- bmoharrisprivatebankingonline\.com
- bmomutualfunds\.com
- bnycash\.bankofny\.com
- bob\-w\.
- bob\.sovereignbank\.com
- bolb\-east\.associatedbank\.com
- bolb\-west\.associatedbank\.com
- bolb\.
- boveda\.banamex\.com\.mx
- bscincky\.com
- business\.macu\.com
- business\.netbankerplus\.com
- business_solutions
- businessaccess\.citibank\.citigroup\.com
- businessappshome
- businessbanking\.cibc\.com
- businessclassonline\.compassbank\.com
- businesslogin
- businessmanager\.com
- businessonline
- businessportal\.mibank\.com
- butterfieldonline\.ky
- bxs\.com
- cashanalyzer\.com
- cashmanager\.mizuhoe\-treasurer\.com
- cashmgmt
- cashmgt
- cashproonline\.bankofamerica\.com
- bankofamerica\.com
- cashproweb\.com/cpwportal
- cbbusinessonline\.com
- cencorpcu\.com
- cfgbusinessaccess\.com
- checkgateway
- checkout\.com/va/login
- cib\.bankofthewest
- cibconline\.cibc\.com
- cimbanque\.net
- citizensbankmoneymanagergps\.com
- cmachm\.w
- cmbmnt\.w
- cmol\.bbt\.com/auth
- cmwirp\.w
- cnbsec1\.
- colb\.
- comerica\.com
- commercebusinessdirect\.com
- commercial\.wachovia\.com
- commercialservices
- connect\.bankcolonial\.com
- connect\.colonialbank\.com
- constitutioncorp\.org
- corpach
- corporate\.epfc\.com
- corporateaccounts
- corporatebankingweb
- corporateconnect\.net
- corpower\.coop
- createcorpwire
- createwire
- cu\.com
- cu\.org
- danskebanka\.lv
- db\-direct\.db\.com
- directline4biz\.com
- directnet\.com
- e\-moneyger
- e\-norvik\.lv
- easywebcpo\.td\.com/waw/idp
- ebanking\-services
- ebemo\.bemobank\.com
- ebill\.highmark\.com
- ecash\.
- ecm\-transfers\.unionbank\.com
- ecms\.unionbank\.com
- efirstbank\.com
- ekp\.lv
- enternetbank\.com
- enterprise2\.openbank\.com
- epd\.uscentral\.org
- eurobankefg\.com
- exact4web
- exness\.com
- express\.53\.com
- expressdeposit\.colonialbank\.com
- fbmedirect\.com
- ffinonline\.com
- ffrontier\.com
- fir
Other Details
This worm deletes the initially executed copy of itself
NOTES:
It monitors the following browsers:
- firefox.exe
It does not have rootkit capabilities.
It does not exploit any vulnerability.
SOLUTION
Step 1
For Windows XP and Windows Server 2003 users, before doing any scans, please make sure you disable System Restore to allow full scanning of your computer.
Step 2
Scan your computer with your Trend Micro product and note files detected as WORM_CRIDEX.AJ
Step 3
Restart in Safe Mode
Step 4
Delete this registry key
Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry.
- In HKEY_CURRENT_USER\Software\Microsoft\Windows NT
- S{8 random characters}
- S{8 random characters}
- In HKEY_CURRENT_USER\Software\Microsoft\Windows NT
- C{8 random characters}
- C{8 random characters}
Step 5
Delete this registry value
Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry.
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
- KB{random number}.exe = "%User Profile%\Application Data\KB{random number}.exe"
- KB{random number}.exe = "%User Profile%\Application Data\KB{random number}.exe"
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings
- GlobalUserOffline = "0"
- GlobalUserOffline = "0"
Step 6
Search and delete these folders
- {drive letter}:\{random folder}
- %User Profile%\Application Data\{random folder name}
Step 7
Search and delete AUTORUN.INF files created by WORM_CRIDEX.AJ that contain these strings
[autorun]
open={random folder}\{random file name}.exe
shell\Open\Command={random folder}\{random file name}.exe
shell\Open\Default=1
shell\Explore\Command={random folder}\{random file name}.exe
shell\Autoplay\command={random folder}\{random file name}.exe
Step 8
Restart in normal mode and scan your computer with your Trend Micro product for files detected as WORM_CRIDEX.AJ. If the detected files have already been cleaned, deleted, or quarantined by your Trend Micro product, no further step is required. You may opt to simply delete the quarantined files. Please check this Knowledge Base page for more information.
Step 9
Scan your computer with your Trend Micro product to delete files detected as WORM_CRIDEX.AJ. If the detected files have already been cleaned, deleted, or quarantined by your Trend Micro product, no further step is required. You may opt to simply delete the quarantined files. Please check this Knowledge Base page for more information.
NOTES:
The created registry keys HKEY_CURRENT_USER\Software\Microsoft\Windows NT\S{8 random characters} and HKEY_CURRENT_USER\Software\Microsoft\Windows NT\C{8 random characters} cannot be identified by the users since there are no reference values in the created keys.
The only way these keys can be identified is by comparing the present keys with a backup if the users have one. Note that these keys need not be deleted since it won't cause the user system any harm.
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