BKDR_CYCBOT.SME3

October 18, 2013
 Analysis by: Roland Marco Dela Paz
 Modified by: Erika Bianca Mendoza
 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

This backdoor appends certain strings to certain URLs and performs HTTP GET requests. It also accesses non-malicious URLs.

This backdoor also acts as a proxy server that intercepts requests from Internet browsers and points them to the proxy server on a port set on the registry. It then monitors the affected system's browsing activity by checking strings related to search engines, social networking, shopping websites, etc. It also checks for antivirus applications by looking at the running processes and checking %Program Files% directory. It also checks a registry below to check Windows Defender installation. Once an AV is found, it sends this information along with the OS version as parameter to a certain URL.

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.

  TECHNICAL DETAILS

File Size:

Varies

Memory Resident:

Yes

Initial Samples Received Date:

13 Jul 2011

Payload:

Compromises system security, Connects to URLs/IPs

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:

  • %User Profile%\Application Data\dwn.exe

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

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:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003, or C:\Users\{user name} on Windows Vista and 7.)

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\dwn.exe"

It modifies the following registry entries to ensure it automatic execution at every system startup:

HKEY_CURRENT_USER\Software\Microsoft\
Windows NT\CurrentVersion\Windows
load = "%User Temp%\csrss.exe"

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

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.)

Download Routine

This backdoor downloads an updated copy of itself from the following website(s):

  • http://{BLOCKED}memory.com
  • http://{BLOCKED}diaportal.com
  • http://{BLOCKED}agearchive.com
  • http://{BLOCKED}4image.com
  • http://{BLOCKED}ontainer.com
  • http://{BLOCKED}oeurosys.com
  • http://{BLOCKED}toblo.com
  • http://{BLOCKED}ogportal.com
  • http://{BLOCKED}stoyou.com
  • http://{BLOCKED}t4you.com

NOTES:

It appends the following strings to the above-mentioned URLs and performs HTTP GET request:

  • {BLOCKED}og/images/{BLOCKED}21.jpg?{params}

The updated version of the backdoor are saved as follows:

  • %Application Data%\Microsoft\conhost.exe
  • %User Temp%\csrss.exe

It also accesses the following non-malicious URLs:

  • http://monochrom.at/polytheism/pictures/TanzenderShiva.jpg
  • http://crazyleafdesign.com/blog/images/share/stumble.png
  • http://crazyleafdesign.com/blog/images/share/facebook.png
  • http://realsoftwaredevelopment.com/WindowsLiveWriter/web-2_0_thumb_1.gif
  • http://gravatar.com/avatar.php?gravatar_id=f2a3889aff6fc9711a3cbcfe64067be1
  • http://gravatar.com/avatar.php?gravatar_id=f2a3889aff6fc9711a3cbcfe64067be2
  • http://folusho.com/wp-content/uploads/2010/09/web-20-what-is-300x251.jpg
  • http://psfk.com/img/icons/twitter.png
  • http://psfk.com/img/icons/facebook.png
  • http://healthylifenow.com/templates/7348/images/header_logo.jpg
  • http://healthylifenow.com/templates/7349/images/header_logo.jpg
  • http://hollandandbarrett.com/images/footer/account.jpg
  • http://hollandandbarrett.com/images/footer/account.gif
  • http://nationsautoelectric.com/images/50-217-1_F_1_.jpg
  • http://nationsautoelectric.com/images/50-217-1_F_2_.jpg
  • http://onlinebizdirectory.com/images/PowerShowBanner.gif
  • http://onlinebizdirectory.com/images/PowerHideBanner.gif
  • http://lostpropaganda.net/blog/pics/3321.jpg
  • http://lostpropaganda.net/blog/pics/3322.jpg
  • http://japanesegreenteaonline.com/assets/images/greentea-cha-1.gif
  • http://japanesegreenteaonline.com/assets/images/greentea-cha-2.gif
  • http://greenherbalteaonline.com/images/greenherbalteagirlholdingcup250.gif
  • http://greenherbalteaonline.com/images/greenherbalteagirlholdingcup350.gif
  • http://onlineinstitute.com/g7/images/logo.jpg
  • http://onlineinstitute.com/g7/images/logo2.jpg
  • http://onlineinstitute.com/g7/images/logo3.jpg
  • http://onlineinstitute.com/g7/images/logo4.jpg
  • http://onlinedatingsecretfriends.com/images/im133.jpg
  • http://onlinedatingsecretfriends.com/images/im134.jpg

Since the extension names of the file downloaded are similar to the above-mentioned malicious URLs, this routine may prevent easy analysis of the backdoor's network activities.

This backdoor also acts as a proxy server that intercepts requests from Internet browsers below and points them to the proxy server on a port set on the registry.

  • Internet Explorer
  • Mozilla Firefox
  • Opera

It then monitors the affected system's browsing activity by checking the following strings related to search engines, social networking, shopping websites, etc.:

  • google.
  • bing.com
  • yahoo.com
  • search.aol.
  • suche.aol.
  • searcht2.aol.
  • gstatic.
  • .yimg.com
  • .bing.net
  • yahoo.
  • aolcdn.
  • scorecardresearch.com
  • brightcove.com
  • .aol.
  • aolsvc.
  • .atwola.
  • .ivwbox.
  • .google
  • .atdmt.
  • .abmr.
  • .tacoda.
  • .adtechus.
  • .autodatadirect.
  • .mapquestapi.
  • .ggpht.
  • .virtualearth.
  • .opera.
  • .microsoft.
  • .wsod.
  • .doubleclick.
  • .ypcdn.
  • .truveo.
  • .tlowdb.
  • mapq.st
  • .dartsearch.
  • .thawte.
  • .2mdn.
  • ytimg.
  • doubleclick.
  • /complete/search
  • start=
  • start=0
  • /imglanding
  • /images
  • http%3A%2F%2F
  • /gen_204
  • err069
  • bing.com/search
  • search.yahoo.com/search
  • aol/search
  • &query=
  • ?query=
  • imdb.
  • wikipedia.
  • youtube.
  • facebook.
  • twitter.
  • amazon.
  • blogger
  • ebay.
  • flickr
  • wikimedia.
  • googleusercontent.
  • googlesyndication.
  • google-analytics.

It stores the gathered information in the following file:

  • %Application Data%\Microsoft\stor.cfg

It also checks for antivirus applications by looking at the running processes and checking %Program Files% directory.

Processes

  • avgnt.exe
  • ccsvchst.exe
  • AvastUI.exe
  • mcagent.exe

Program Files

  • Avira*
  • Norton*
  • Symantec*
  • Alwil Software*
  • Avast*
  • McAfee*

It also checks the registry below to check Windows Defender installation:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows Defender

Once an AV is found, it sends this information along with the OS version as parameter to the URL below:

  • http://{BLOCKED}ats.com/images/logo.png

  SOLUTION

Minimum Scan Engine:

9.200

FIRST VSAPI PATTERN FILE:

8.288.10

FIRST VSAPI PATTERN DATE:

14 Jul 2011

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

Identify and terminate files detected as BKDR_CYCBOT.SME3

[ Learn More ]
  1. Windows Task Manager may not display all running processes. In this case, please use a third-party process viewer, preferably Process Explorer, to terminate the malware/grayware/spyware file. You may download the said tool here.
  2. 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.
  3. If the detected file is not displayed in either Windows Task Manager or Process Explorer, continue doing the next steps.

Step 3

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 number}
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\Winlogon
    • Shell = explorer.exe,%User Profile%\Application Data\dwn.exe
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    • conhost = %User Profile%\Application Data\Microsoft\conhost.exe

Step 4

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_CURRENT_USER\Softwar\\Microsoft\Windows NT\CurrentVersio\\Windows
    • From: load = %User Temp%\csrss.exe
      To: load = ""
  • 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

Step 5

Search and delete these files

[ Learn More ]
There may be some 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
  • %Application Data%\Microsoft\stor.cfg

Step 6

Scan your computer with your Trend Micro product to delete files detected as BKDR_CYCBOT.SME3. 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

Search and delete the files detected as BKDR_CYCBOT.SME3

*Note: Some component files may be 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.

To stop the malware/grayware from running when certain files are opened:

For Windows 2000, Windows XP, and Windows Server 2003:

  1. Right-click Start then click Search....
  2. In the Named input box, type the name of the file that was detected earlier.
  3. In the Look In drop-down list, select My Computer then press Enter.
  4. Once located, select the file then press SHIFT+DELETE to delete it.

For Windows Vista and Windows 7:

  1. Click Start>Computer.
  2. In the Search Computer input box, type the name of the file detected earlier, and press Enter.
  3. Once located, select the file then press SHIFT+DELETE to delete it.
    *Note: Read the following Microsoft page if these steps do not work on Windows 7.

NOTES:

RECOMMENDATIONS

This malware is detected and removed by the latest Trend Micro anti-malware engine and pattern. Always keep pattern files and engines up-to-date. To know more about updating your Trend Micro product's pattern, please refer to the following Trend Micro support page:


Note: The steps apply for specific products indicated in the page.

To actively detect and protect your machine, enable real-time scanning of your Trend Micro anti-malware product. Refer to the following Trend Micro support page to know more about enabling real-time scanning in your Trend Micro product:

To enable Firewall to protect against threats: How do I enable or disable the Personal Firewall of Trend Micro Internet Security?

  • Be aware of social engineering attacks.
  • Avoid accessing the listed malicious URLs to prevent possible re-infection.
  • Monitor network connections for any suspicious connection or connectivity.
  • Regularly update list of untrusted websites.
  • Avoid downloading software cracks and/or pirated applications.
  • Block malware related websites.
  • Delete files in the %User Temp% folder.


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