BKDR_CYCBOT.BU

October 08, 2012
 Analysis by: Roland Marco Dela Paz
 ALIASES:

Microsoft : Backdoor:Win32/Cycbot.B; Symantec : Backdoor.Cycbot!gen3

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

This backdoor drops copies of itself onto the affected system. It executes certain commands from a remote malicious user, and connects to certain websites in order to download more malicious files or an updated copy of itself.

This backdoor may be downloaded by other malware/grayware/spyware from remote sites. It may be unknowingly downloaded by a user while visiting malicious websites.

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

  TECHNICAL DETAILS

File Size:

166,912 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

15 Apr 2011

Payload:

Drops files, Connects to URLs/Ips, Downloads files, Compromises system security

Arrival Details

This backdoor may be downloaded by other malware/grayware/spyware from remote sites.

It may be unknowingly downloaded by a user while visiting malicious websites.

Installation

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

  • %User Profile%\Application Data\Microsoft\conhost.exe
  • %User Profile%\Application Data\dwm.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 drops the following non-malicious file:

  • %User Profile%\Application Data\9EAE.6BA - log file

(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.)

Autostart Technique

This backdoor adds the following registry entries to enable its automatic execution at every system startup:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
conhost = %User Profile%\Application Data\Microsoft\conhost.exe

HKEY_CURRENT_USER\Software\Microsoft\
Windows NT\CurrentVersion\Winlogon
Shell = explorer.exe,%User Profile%\Application Data\dwm.exe

Other System Modifications

This backdoor adds the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings
ProxyServer = http=127.0.0.1:{port number}

It modifies the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings
ProxyEnable = 1

(Note: The default value data of the said registry entry is 0.)

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Hardware Profiles\0001\Software\
Microsoft\windows\CurrentVersion\
Internet Settings
ProxyEnable = 1

(Note: The default value data of the said registry entry is 0.)

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Hardware Profiles\Current\Software\
Microsoft\windows\CurrentVersion\
Internet Settings
ProxyEnable = 1

(Note: The default value data of the said registry entry is 0.)

HKEY_CURRENT_CONFIG\Software\Microsoft\
windows\CurrentVersion\Internet Settings
ProxyEnable = 1

(Note: The default value data of the said registry entry is 0.)

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile
EnableFirewall = 0

(Note: The default value data of the said registry entry is 1.)

Backdoor Routine

This backdoor executes the following commands from a remote malicious user:

  • search and open files
  • download updated copy of itself
  • download and execute other possibly malicious file(s)
  • send installation report to the server
  • redirect HTTP traffic to a specific website
  • uninstall itself

It connects to the following websites to send and receive information:

  • http://{BLOCKED}234.motostyleclub.com
  • http://{BLOCKED}inewarez.com
  • http://{BLOCKED}space.com
  • http://{BLOCKED}santa.com
  • http://{BLOCKED}ebookshop.com
  • http://{BLOCKED}temsonline.com
  • http://{BLOCKED}programmingshool.com
  • http://{BLOCKED}rddrivesoft.com
  • http://{BLOCKED}bilesoftonline.com
  • http://{BLOCKED}otostoreonline.com
  • http://{BLOCKED}devicescatalog.com
  • http://{BLOCKED}sonline.com
  • http://{BLOCKED}rshoponline.com
  • http://{BLOCKED}lddisordervideo.com
  • http://{BLOCKED}esbee.com
  • http://{BLOCKED}futures.com
  • http://{BLOCKED}inpeoplelist.com
  • http://{BLOCKED}ack-1.com
  • http://{BLOCKED}etalfunclub.com
  • http://{BLOCKED}amplestore.com
  • http://{BLOCKED}ilesoftonline.com
  • http://{BLOCKED}pportcenter.com

NOTES:
It monitors Internet browser's activity and checks for the following strings of popular websites such as search engines and social networking sites in order to alter HTTP traffic:

  • &query=
  • .2mdn.
  • .abmr.
  • .adtechus.
  • .aol.
  • .atdmt.
  • .atwola.
  • .autodatadirect.
  • .bing.net
  • .dartsearch.
  • .doubleclick.
  • .doubleclick.net
  • .ggpht.
  • .google
  • .ivwbox.
  • .mapquestapi.
  • .microsoft.
  • .opera.
  • .tacoda.
  • .thawte.
  • .tlowdb.
  • .truveo.
  • .virtualearth.
  • .wsod.
  • .yimg.com
  • .ypcdn.
  • /complete/search
  • /gen_204
  • /images
  • /imglanding
  • ?query=
  • amazon.
  • aol/search
  • aolcdn.
  • aolsvc.
  • bing.com
  • bing.com/search
  • blogger
  • brightcove.com
  • doubleclick.
  • doubleclick.net
  • ebay.
  • err069
  • facebook.
  • flickr
  • google-analytics.
  • google.
  • googlesyndication.
  • googleusercontent.
  • gstatic.
  • http%3A%2F%2F
  • imdb.
  • mapq.st
  • msn.com
  • scorecardresearch.com
  • search.aol.
  • search.yahoo.com/search
  • searcht2.aol.
  • start=
  • start=0
  • suche.aol.
  • twitter.
  • wikimedia.
  • wikipedia.
  • yahoo.
  • yahoo.com
  • youtube.
  • ytimg.
It acts as a proxy server to intercept requests of the following Internet browsers and points them to its configured proxy server:
  • Internet Explorer
  • Mozilla Firefox
  • Opera
It connects to the following compromised sites to download updated copy(ies) of itself and other possibly malicious file(s):
  • http://{BLOCKED}eafdesign.com/blog/images/share/facebook.png
  • http://{BLOCKED}eafdesign.com/blog/images/share/stumble.png
  • http://{BLOCKED}o.com/wp-content/uploads/2010/09/web-20-what-is-300x251.jpg
  • http://{BLOCKED}ar.com/avatar.php?gravatar_id=f2a3889aff6fc9711a3cbcfe64067be1
  • http://{BLOCKED}ar.com/avatar.php?gravatar_id=f2a3889aff6fc9711a3cbcfe64067be2
  • http://{BLOCKED}erbalteaonline.com/images/greenherbalteagirlholdingcup250.gif
  • http://{BLOCKED}erbalteaonline.com/images/greenherbalteagirlholdingcup350.gif
  • http://{BLOCKED}ylifenow.com/templates/7348/images/header_logo.jpg
  • http://{BLOCKED}hylifenow.com/templates/7349/images/header_logo.jpg
  • http://{BLOCKED}dandbarrett.com/images/footer/account.gif
  • http://{BLOCKED}dandbarrett.com/images/footer/account.jpg
  • http://{BLOCKED}segreenteaonline.com/assets/images/greentea-cha-1.gif
  • http://{BLOCKED}egreenteaonline.com/assets/images/greentea-cha-2.gif
  • http://{BLOCKED}paganda.net/blog/pics/3321.jpg
  • http://{BLOCKED}opaganda.net/blog/pics/3322.jpg
  • http://{BLOCKED}rom.at/polytheism/pictures/TanzenderShiva.jpg
  • http://{BLOCKED}sautoelectric.com/images/50-217-1_F_1_.jpg
  • http://{BLOCKED}sautoelectric.com/images/50-217-1_F_2_.jpg
  • http://{BLOCKED}bizdirectory.com/images/PowerHideBanner.gif
  • http://{BLOCKED}bizdirectory.com/images/PowerShowBanner.gif
  • http://{BLOCKED}atingsecretfriends.com/images/im133.jpg
  • http://{BLOCKED}datingsecretfriends.com/images/im134.jpg
  • http://{BLOCKED}institute.com/g7/images/logo.jpg
  • http://{BLOCKED}institute.com/g7/images/logo2.jpg
  • http://{BLOCKED}institute.com/g7/images/logo3.jpg
  • http://{BLOCKED}institute.com/g7/images/logo4.jpg
  • http://{BLOCKED}k.com/img/icons/facebook.png
  • http://{BLOCKED}k.com/img/icons/twitter.png
  • http://{BLOCKED}ftwaredevelopment.com/WindowsLiveWriter/web-2_0_thumb_1.gif
It disables services containing any of the following strings:
  • AlwilSoftware*
  • Avast
  • Avast*
  • AvastUI.exe
  • Avira
  • Avira*
  • BitDefender
  • Dr.Web
  • ESETNOD32
  • Kaspersky
  • McAfee
  • McAfee*
  • Norton
  • Norton*
  • Symantec*
  • WindowsDefender
  • avast
  • avgnt.exe
  • avira
  • bitdef
  • ccsvchst.exe
  • drweb
  • kasper
  • mcafee
  • mcagent.exe
  • nod32
  • norton

  SOLUTION

Minimum Scan Engine:

8.900

FIRST VSAPI PATTERN FILE:

7.978.11

FIRST VSAPI PATTERN DATE:

15 Apr 2011

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

Identify and terminate files detected as BKDR_CYCBOT.BU

[ Learn More ]
  1. If the detected file is displayed in either Windows Task Manager or Process Explorer but you cannot delete it, restart your computer in safe mode. To do this, refer to this link for the complete steps.
  2. If the detected file is not displayed in either Windows Task Manager or Process Explorer, continue doing the next steps.

Step 3

Search and delete this file

[ Learn More ]
There may be some component files that are hidden. Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden files and folders in the search result.  %User Profile%\Application Data\9EAE.6BA

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\Internet Settings
    • ProxyServer = http=127.0.0.1:{port}
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    • conhost = %User Profile%\Application Data\Microsoft\conhost.exe
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\Winlogon
    • Shell = explorer.exe,%User Profile%\Application Data\dwm.exe

Step 5

Restore this modified 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\Internet Settings
    • From: ProxyEnable = 1
      To: ProxyEnable = 0
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Hardware Profiles\0001\Software\Microsoft\windows\CurrentVersion\Internet Settings
    • From: ProxyEnable = 1
      To: ProxyEnable = 0
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Hardware Profiles\Current\Software\Microsoft\windows\CurrentVersion\Internet Settings
    • From: ProxyEnable = 1
      To: ProxyEnable = 0
  • In HKEY_CURRENT_CONFIG\Software\Microsoft\windows\CurrentVersion\Internet Settings
    • From: ProxyEnable = 1
      To: ProxyEnable = 0
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile
    • From: EnableFirewall = 0
      To: EnableFirewall = 1

Step 6

Scan your computer with your Trend Micro product to delete files detected as BKDR_CYCBOT.BU. 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.


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