Threat Encyclopedia

BKDR_CRIDEX.CHX

Publish date: April 18, 2013

ANALYSIS BY

Anthony Joe Melgarejo


ALIASES:

Win32.Malware!Drop (Sunbelt), W32/Bublik.AKVS!tr (Fortinet)

PLATFORM:

Windows 2000, Windows Server 2003, Windows XP (32-bit, 64-bit), Windows Vista (32-bit, 64-bit), Windows 7 (32-bit, 64-bit)

OVERALL RISK RATING:
DAMAGE POTENTIAL:
DISTRIBUTION POTENTIAL:
REPORTED INFECTION:

  • Threat Type:Backdoor

  • Destructiveness:No

  • Encrypted: Yes

  • In the wild: Yes

OVERVIEW

Infection Channel:

Dropped by other malware, Downloaded from the Internet, Spammed via email


This backdoor is served via a spammed message that leads to a Blackhole Exploit Kit. It monitors the Internet Explorer address bar and title bar for strings that are related to certain banking websites.

To get a one-glance comprehensive view of the behavior of this Backdoor, refer to the Threat Diagram shown below.

This backdoor arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

It executes commands from a remote malicious user, effectively compromising the affected system. It connects to a website to send and receive information.

It deletes the initially executed copy of itself.

TECHNICAL DETAILS

File Size:

Varies

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

18 Apr 2013

Payload:

Compromises system security, Connects to URLs/IPs, Steals information

Arrival Details

This backdoor 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 backdoor drops the following copies of itself into the affected system and executes them:

  • %Application Data%\KB{random number}.exe

(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Roaming on Windows Vista and 7.)

It drops the following files:

  • %User Temp%\exp{number}.tmp.bat - used to delete the initially executed copy. This file is deleted after execution

(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista and 7.)

It creates the following folders:

  • %Application Data%\{random folder name}

(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Roaming on Windows Vista and 7.)

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\XMS{8 random characters}
  • Local\XMF{8 random characters}
  • Local\XMR{8 random characters}
  • Local\XMQ{8 random characters}
  • Local\XMB{8 random characters}

It injects codes into the following process(es):

  • explorer.exe

Autostart Technique

This backdoor 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 = "%Application Data%\KB{random number}.exe"

Other System Modifications

This backdoor adds the following registry keys:

HKEY_CURRENT_USER\Software\Microsoft\
Windows NT\{random value 1}

HKEY_CURRENT_USER\Software\Microsoft\
Windows NT\{random value 2}

It adds the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings
GlobalUserOffline = "0"

HKEY_CURRENT_USER\Software\Microsoft\
Windows NT\{random value 2}
Default = "{script containing bank-related strings}"

Backdoor Routine

This backdoor 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 websites to send and receive information:

  • http://{BLOCKED}.{BLOCKED}.90.92:8080/jsbqmCA/hCpyb/Cnw/ED
  • http://{BLOCKED}.{BLOCKED}.204.148:8080/jsbqmCA/hCpyb/Cnw/ED
  • http://{BLOCKED}.{BLOCKED}.167.124:8080/jsbqmCA/hCpyb/Cnw/ED
  • http://{BLOCKED}.{BLOCKED}.36.93:8080/jsbqmCA/hCpyb/Cnw/ED
  • http://{BLOCKED}.{BLOCKED}.143.90:8080/jsbqmCA/hCpyb/Cnw/ED
  • http://{BLOCKED}.{BLOCKED}.201.180:8080/jsbqmCA/hCpyb/Cnw/ED
  • http://{BLOCKED}.{BLOCKED}.155.222:8080/jsbqmCA/hCpyb/Cnw/ED
  • http://{BLOCKED}.{BLOCKED}.156.20:8080/jsbqmCA/hCpyb/Cnw/ED
  • http://{BLOCKED}.{BLOCKED}.208.130:8080/jsbqmCA/hCpyb/Cnw/ED
  • http://{BLOCKED}.{BLOCKED}.218.123:8080/jsbqmCA/hCpyb/Cnw/ED
  • http://{BLOCKED}.{BLOCKED}.130.98:8080/jsbqmCA/hCpyb/Cnw/ED
  • http://{BLOCKED}.{BLOCKED}.94.212:8080/jsbqmCA/hCpyb/Cnw/ED
  • http://{BLOCKED}.{BLOCKED}.160.142:8080/jsbqmCA/hCpyb/Cnw/ED
  • http://{BLOCKED}.{BLOCKED}.200.151:8080/jsbqmCA/hCpyb/Cnw/ED
  • http://{BLOCKED}.{BLOCKED}.99.48:8080/jsbqmCA/hCpyb/Cnw/ED
  • http://{BLOCKED}.{BLOCKED}.207.52:8080/jsbqmCA/hCpyb/Cnw/ED
  • http://{BLOCKED}.{BLOCKED}.135.227:8080/jsbqmCA/hCpyb/Cnw/ED
  • http://{BLOCKED}.{BLOCKED}.53.168:8080/jsbqmCA/hCpyb/Cnw/ED
  • http://{BLOCKED}.{BLOCKED}.5.195:8080/jsbqmCA/hCpyb/Cnw/ED
  • http://{BLOCKED}.{BLOCKED}.74.5:8080/jsbqmCA/hCpyb/Cnw/ED
  • http://{BLOCKED}.{BLOCKED}.3.246:8080/jsbqmCA/hCpyb/Cnw/ED
  • http://{BLOCKED}.{BLOCKED}.3.246:8080/jsbqmCA/hCpyb/Cnw/ED
  • http://{BLOCKED}.{BLOCKED}.106.162:8080/jsbqmCA/hCpyb/Cnw/ED

Other Details

This backdoor deletes the initially executed copy of itself

NOTES:

This backdoor monitors browser activities of the affected system, specifically the address bar or title bar, using the following strings:

  • \.com/k1/
  • /ach/
  • /authentication/zbf/k/
  • /bb/logon/
  • /cashman/
  • /cashplus/
  • ebanking-ch2\.ubs\.com
  • /clkccm/
  • /cmmain\.cfm
  • nbad\.com
  • postfinance\.ch
  • abnamro\.nl
  • rabobank\.nl
  • anz\.com
  • nab\.com\.au
  • ing\.nl
  • snsbank\.nl
  • directnet\.com
  • /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
  • firstbancorp\.com
  • firstbanks\.com
  • firstcitizens\.com
  • fnfgbusinessonline\.enterprisebanker\.com
  • fxpayments\.americanexpress\.com
  • geonline\.lv
  • global\-ebanking\.com
  • global1\.onlinebank\.com
  • globalink\.leumiusa\.com
  • goldleaf
  • guard\.scotiabank\.com
  • handelsbanken\.lv
  • hbcash\.exe
  • hblibank\.com
  • hbproxy\.exe
  • hellenicnetbanking\.com
  • hillsbank\.com
  • hiponet\.lv
  • hkbea
  • hsbc\.com\.mx
  • i\-linija\.lt
  • ib\.dnb\.lv
  • ibanking\-services\.com
  • ibbpl2\.com
  • ibbpowerlink\.com
  • ibbusinessnet\.com
  • ibcbankonline\.ibc\.com
  • ifxmanager\.bankofny\.com
  • ifxmanager\.bnymellon\.com
  • inetbanker
  • injectreceiver
  • internationalbanking\.
  • internationalpayments\.
  • internet\-ebanking\.com
  • internetbanker\.cc
  • itinternet\.net
  • itreasury\.amsouth\.com
  • ktt\.key\.com
  • lakelandbank\.com
  • libertymutualbusinessdirect\.com
  • lionbank\.com
  • login_business\.asp
  • logincm
  • loyalbank\.com
  • lv\.unicreditbanking\.net
  • marfinbank\.com\.cy
  • mbachexpress\.com
  • mcb\-home\.com/online
  • memberach
  • metrobankdirect\.com
  • midatlanticcorp\.org
  • moneymanagergps\.com
  • multinetbank\.eu
  • my\.statestreet\.com
  • mycorporate\.org
  • myonlineservices\.cbolobank\.com
  • nashvillecitizensbank\.com
  • nationalcity\.com/consultnc
  • nbarizona\.com/login_business\.jsp
  • nbb\.controlsecure\.com
  • ncms\-inc\.com
  • netteller
  • nfbconnect\.com
  • northbaybancorp\.com
  • northerntrust\.com
  • norvik\.lv
  • nsbank\.com
  • ntrs\.com
  • nubi
  • olb\.
  • olb\.ent\.com/business/
  • online\-offshore\.lloydstsb\.com
  • online\.1stnb\.com

SOLUTION

Minimum Scan Engine:

9.300

FIRST VSAPI PATTERN FILE:

9.864.03

FIRST VSAPI PATTERN DATE:

18 Apr 2013

VSAPI OPR PATTERN File:

9.865.00

VSAPI OPR PATTERN Date:

19 Apr 2013

Step 1

Before doing any scans, Windows XP, Windows Vista, and Windows 7 users must disable System Restore to allow full scanning of their computers.

Step 2

Scan your computer with your Trend Micro product and note files detected as BKDR_CRIDEX.CHX

Step 3

Restart in Safe Mode

[ Learn More ]

Step 4

Delete this registry value

[ Learn More ]

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 = "%Application Data%\KB{random number}.exe"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings
    • GlobalUserOffline = "0"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows NT\{random value 2}
    • Default = "{script containing bank-related strings}"

Step 5

Search and delete this folder

[ Learn More ]
Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden folders in the search result.
  • %Application Data%\{random folder name}

Step 6

Restart in normal mode and scan your computer with your Trend Micro product for files detected as BKDR_CRIDEX.CHX. 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 7

The following created registry key(s) cannot be identified by the user since there are no reference values in the created key. The only way it can be identified is by comparing the present keys with a backup of the system registry. Note that the said key(s) do not have to be deleted since it won't be harmful to the system:

  • In HKEY_CURRENT_USER\Software\Microsoft\Windows NT
    • {random value 2}
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows NT
    • {random value 1}


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