BKDR_CYCBOT.SS

October 09, 2012
 Analysis by: Sabrina Lei Sioting
 ALIASES:

Backdoor:Win32/Cycbot.G (Microsoft); BackDoor-EXI.gen.c (Nai); W32/Goolbot.D.gen!Eldorado (FProt)

 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 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:

187,392 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

23 Jul 2012

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\Microsoft\svchost.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 files:

  • %User Profile%\Application Data\Microsoft\stor.cfg

(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
svchost = "%User Profile%\Application Data\Microsoft\svchost.exe"

Other System Modifications

This backdoor modifies the following registry key(s)/entry(ies) as part of its installation routine:

HKEY_CURRENT_USER\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.)

Other Details

This backdoor connects to the following possibly malicious URL:

  • http://{BLOCKED}edating.com/images/attend_for_free/attend{number}.jpg?tq={random characters}
  • http://{BLOCKED}edating.com/successStories.cgi?tq={random characters}
  • http://{BLOCKED}emonitoring.com/images/im13{number}.jpg?tq={random characters}
  • http://{BLOCKED}sstore.com/images/im13{number}.jpg?tq={random characters}
  • http://{BLOCKED}udiodevice.com/images/im13{number}.jpg?tq={random characters}
  • http://{BLOCKED}linedatingtips.net/images/dating1.jpg?tq={random characters}
  • http://{BLOCKED}ykillerpro.com/img/eslogo.gif?tq={random characters}
  • http://{BLOCKED}wcounter.com/images/im13{number}.jpg?tq={random characters}
  • http://{BLOCKED}boardstest.com/images/im13{number}.jpg?tq={random characters}
  • http://{BLOCKED}rchive.com/images/im13{number}.jpg?tq={random characters}
  • http://{BLOCKED}ro.com/images/logo-1.jpg?tq={random characters}
  • http://{BLOCKED}tyourpc-11.com/cgi-bin/cycle_report.cgi
  • http://{BLOCKED}mywebconnection.com/images/im13{number}.jpg?tq={random characters}
  • http://{BLOCKED}driversonline.com/images/im13{number}.jpg?tq={random characters}
  • http://{BLOCKED}.cn/2010/10/10/20101010095345843723.jpg?tq={random characters}
  • http://{BLOCKED}.cn/2010/10/10/20101010095345843724.jpg?tq={random characters}
  • http://{BLOCKED}n/jianfei/dier.jpg?tq={random characters}
  • http://{BLOCKED}n/jianfei/dier2.jpg?tq={random characters}
  • http://{BLOCKED}.com/images/im13{number}.jpg?tq={random characters}
  • http://{BLOCKED}.com/images/im13{number}.jpg?tq={random characters}

  SOLUTION

Minimum Scan Engine:

9.200

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.SS

[ 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

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_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    • svchost = "%User Profile%\Application Data\Microsoft\svchost.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_CONFIG\Software\Microsoft\windows\CurrentVersion\Internet Settings
    • From: ProxyEnable = "1"
      To: ProxyEnable = 0

Step 5

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\Microsoft\stor.cfg

Step 6

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