TROJ_AGENT.BEKB


 ALIASES:

Backdoor:Win32/Jukbot.B (Microsoft); Suspicious.MH690 (Symantec)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW


This Trojan 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:

1,562,689 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

06 Feb 2013

Arrival Details

This Trojan 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 Trojan creates the following folders:

  • %System Root%\DOCUME~1
  • %System Root%\DOCUME~1\ADMINI~1
  • %User Profile%\LOCALS~1
  • %User Profile%\Application Data\uTorrent
  • %System Root%\Documents and Settings\Administrator
  • %User Profile%\uTorrent\Cache
  • %Program Files%\uTorrent
  • %User Profile%\uTorrent\apps

(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.. %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.. %Program Files% is the default Program Files folder, usually C:\Program Files in Windows 2000, Server 2003, and XP (32-bit), Vista (32-bit), and 7 (32-bit), or C:\Program Files (x86) in Windows XP (64-bit), Vista (64-bit), and 7 (64-bit).)

Autostart Technique

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
uTorrent = "%Program Files%\uTorrent\uTorrent.exe /MINIMIZED"

Other System Modifications

This Trojan modifies the following file(s):

  • %User Profile%\Application Data\Microsoft

(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 deletes the following files:

  • %User Temp%\nsa1.tmp
  • %User Temp%\9F0A~1.EXE

(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 adds the following registry keys:

HKEY_CURRENT_USER\Software\Classes\
FalconBetaAccount

HKEY_CURRENT_USER\Software\Classes\
.torrent

HKEY_CURRENT_USER\Software\Classes\
uTorrent\DefaultIcon

HKEY_CLASSES_ROOT\MIME\Database\
Content Type\application/x-bittorrent

HKEY_CURRENT_USER\Software\Classes\
MIME\Database\Content Type\
application/x-bittorrent

HKEY_CURRENT_USER\Software\Classes\
uTorrent\shell\open\
command

HKEY_CURRENT_USER\Software\Classes\
uTorrent\Content Type

HKEY_CURRENT_USER\Software\Classes\
.btsearch

HKEY_CLASSES_ROOT\MIME\Database\
Content Type\application/x-bittorrentsearchdescription+xml

HKEY_CURRENT_USER\Software\Classes\
MIME\Database\Content Type\
application/x-bittorrentsearchdescription+xml

HKEY_CURRENT_USER\Software\Classes\
Magnet

HKEY_CURRENT_USER\Software\Classes\
Magnet\shell\open\
command

HKEY_CURRENT_USER\Software\Classes\
Magnet\DefaultIcon

HKEY_CURRENT_USER\Software\Classes\
.torrent\OpenWithProgids

HKEY_CURRENT_USER\Software\Classes\
.btsearch\OpenWithProgids

HKEY_CURRENT_USER\Software\Classes\
Applications\uTorrent.exe\shell

HKEY_CURRENT_USER\Software\Classes\
Applications\uTorrent.exe\shell\
open\command

HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows\CurrentVersion\Uninstall\
uTorrent

HKEY_CURRENT_USER\Software\BitTorrent\
uTorrent

It adds the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\rcmdsvc
Description = "Windows Resource Kit"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\AuthorizedApplications\
List
%System%\cipzab.exe = "%System%\cipzab.exe:*:Enabled:Microsoft (R) Internetal IExplore"

HKEY_CURRENT_USER\FalconBetaAccount
remote_access_client_id = "6620459923"

HKEY_CURRENT_USER\.torrent
Content Type = "application/x-bittorrent"

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
MIME\Database\Content Type\
application/x-bittorrent
Extension = ".torrent"

HKEY_CURRENT_USER\MIME\Database\
Content Type\application/x-bittorrent
Extension = ".torrent"

HKEY_CURRENT_USER\.btsearch
Content Type = "application/x-bittorrentsearchdescription+xml"

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
MIME\Database\Content Type\
application/x-bittorrentsearchdescription+xml
Extension = ".btsearch"

HKEY_CURRENT_USER\MIME\Database\
Content Type\application/x-bittorrentsearchdescription+xml
Extension = ".btsearch"

HKEY_CURRENT_USER\Magnet
Content Type = "application/x-magnet"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
uTorrent
DisplayIcon = "%Program Files%\uTorrent\uTorrent.exe,0"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
uTorrent
DisplayName = "µTorrent"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
uTorrent
DisplayVersion = "3.2.0"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
uTorrent
UninstallString = "%Program Files%\uTorrent\uTorrent.exe /UNINSTALL"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
uTorrent
InstallLocation = "%Program Files%\uTorrent"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
uTorrent
NoModify = "1"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
uTorrent
NoRepair = "1"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
uTorrent
URLInfoAbout = "http://www.{BLOCKED}nt.com"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\AuthorizedApplications\
List
%Program Files%\uTorrent\uTorrent.exe = "%Program Files%\uTorrent\uTorrent.exe:*:Enabled:µTorrent"

HKEY_CURRENT_USER\Software\BitTorrent\
uTorrent
Revision = "6a9f"

Dropping Routine

This Trojan drops the following files:

  • %User Temp%\Å©·¢¹æÁö.exe
  • %User Temp%\uTorrent-3.2.exe
  • %User Profile%\Microsoft\Crypto
  • %User Profile%\Crypto\RSA
  • %User Profile%\RSA\S-1-5-21-4025279379-4087772427-2915903831-500
  • %User Profile%\uTorrent\settings.dat.new
  • %Program Files%\uTorrent\uTorrent.exe
  • %Start Menu%\µTorrent.lnk
  • %Desktop%\µTorrent.lnk
  • %User Profile%\Quick Launch\µTorrent.lnk
  • %User Profile%\apps\player.btapp
  • %System%\cipzab.exe

(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.. %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.. %Program Files% is the default Program Files folder, usually C:\Program Files in Windows 2000, Server 2003, and XP (32-bit), Vista (32-bit), and 7 (32-bit), or C:\Program Files (x86) in Windows XP (64-bit), Vista (64-bit), and 7 (64-bit).. %Start Menu% is the current user's Start Menu folder, which is usually C:\Windows\Start Menu or C:\Documents and Settings\{User name}\Start Menu on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Roaming\Microsoft\Windows\Start Menu on Windows Vista and 7.. %Desktop% is the current user's desktop, which is usually C:\Documents and Settings\{User Name}\Desktop on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\Desktop on Windows Vista and 7.. %System% is the Windows system folder, which is usually C:\Windows\System32.)

Other Details

This Trojan connects to the following possibly malicious URL:

  • http://update.{BLOCKED}nt.com/installstats.php?{random characters}

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine:

9.300

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

Restart in Safe Mode

[ Learn More ]

Step 3

Delete this registry key

[ 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\Classes
    • FalconBetaAccount
  • In HKEY_CURRENT_USER\Software\Classes
    • .torrent
  • In HKEY_CURRENT_USER\Software\Classes\uTorrent
    • DefaultIcon
  • In HKEY_CLASSES_ROOT\MIME\Database\Content Type
    • application/x-bittorrent
  • In HKEY_CURRENT_USER\Software\Classes\MIME\Database\Content Type
    • application/x-bittorrent
  • In HKEY_CURRENT_USER\Software\Classes\uTorrent\shell\open
    • command
  • In HKEY_CURRENT_USER\Software\Classes\uTorrent
    • Content Type
  • In HKEY_CURRENT_USER\Software\Classes
    • .btsearch
  • In HKEY_CLASSES_ROOT\MIME\Database\Content Type
    • application/x-bittorrentsearchdescription+xml
  • In HKEY_CURRENT_USER\Software\Classes\MIME\Database\Content Type
    • application/x-bittorrentsearchdescription+xml
  • In HKEY_CURRENT_USER\Software\Classes
    • Magnet
  • In HKEY_CURRENT_USER\Software\Classes\Magnet\shell\open
    • command
  • In HKEY_CURRENT_USER\Software\Classes\Magnet
    • DefaultIcon
  • In HKEY_CURRENT_USER\Software\Classes\.torrent
    • OpenWithProgids
  • In HKEY_CURRENT_USER\Software\Classes\.btsearch
    • OpenWithProgids
  • In HKEY_CURRENT_USER\Software\Classes\Applications\uTorrent.exe
    • shell
  • In HKEY_CURRENT_USER\Software\Classes\Applications\uTorrent.exe\shell\open
    • command
  • In HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Uninstall
    • uTorrent
  • In HKEY_CURRENT_USER\Software\BitTorrent
    • uTorrent

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
    • uTorrent = "%Program Files%\uTorrent\uTorrent.exe /MINIMIZED"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\rcmdsvc
    • Description = "Windows Resource Kit"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\AuthorizedApplications\List
    • %System%\cipzab.exe = "%System%\cipzab.exe:*:Enabled:Microsoft (R) Internetal IExplore"
  • In HKEY_CURRENT_USER\FalconBetaAccount
    • remote_access_client_id = "6620459923"
  • In HKEY_CURRENT_USER\.torrent
    • Content Type = "application/x-bittorrent"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\MIME\Database\Content Type\application/x-bittorrent
    • Extension = ".torrent"
  • In HKEY_CURRENT_USER\MIME\Database\Content Type\application/x-bittorrent
    • Extension = ".torrent"
  • In HKEY_CURRENT_USER\.btsearch
    • Content Type = "application/x-bittorrentsearchdescription+xml"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\MIME\Database\Content Type\application/x-bittorrentsearchdescription+xml
    • Extension = ".btsearch"
  • In HKEY_CURRENT_USER\MIME\Database\Content Type\application/x-bittorrentsearchdescription+xml
    • Extension = ".btsearch"
  • In HKEY_CURRENT_USER\Magnet
    • Content Type = "application/x-magnet"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\uTorrent
    • DisplayIcon = "%Program Files%\uTorrent\uTorrent.exe,0"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\uTorrent
    • DisplayName = "µTorrent"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\uTorrent
    • DisplayVersion = "3.2.0"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\uTorrent
    • UninstallString = "%Program Files%\uTorrent\uTorrent.exe /UNINSTALL"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\uTorrent
    • InstallLocation = "%Program Files%\uTorrent"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\uTorrent
    • NoModify = "1"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\uTorrent
    • NoRepair = "1"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\uTorrent
    • URLInfoAbout = "http://www.{BLOCKED}nt.com"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\AuthorizedApplications\List
    • %Program Files%\uTorrent\uTorrent.exe = "%Program Files%\uTorrent\uTorrent.exe:*:Enabled:µTorrent"
  • In HKEY_CURRENT_USER\Software\BitTorrent\uTorrent
    • Revision = "6a9f"

Step 5

Search and delete these components

[ Learn More ]
There may be some components 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 Temp%\Å©·¢¹æÁö.exe
  • %User Temp%\uTorrent-3.2.exe
  • %User Profile%\Microsoft\Crypto
  • %User Profile%\Crypto\RSA
  • %User Profile%\RSA\S-1-5-21-4025279379-4087772427-2915903831-500
  • %User Profile%\uTorrent\settings.dat.new
  • %Program Files%\uTorrent\uTorrent.exe
  • %Start Menu%\µTorrent.lnk
  • %Desktop%\µTorrent.lnk
  • %User Profile%\Quick Launch\µTorrent.lnk
  • %User Profile%\apps\player.btapp
  • %System%\cipzab.exe

Step 6

Search and delete these folders

[ 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.
  • %System Root%\DOCUME~1
  • %System Root%\DOCUME~1\ADMINI~1
  • %User Profile%\LOCALS~1
  • %User Profile%\Application Data\uTorrent
  • %System Root%\Documents and Settings\Administrator
  • %User Profile%\uTorrent\Cache
  • %Program Files%\uTorrent
  • %User Profile%\uTorrent\apps

Step 7

Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_AGENT.BEKB. 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 8

Restore deleted/modified files and/or registry entries from backup

*Note: Only Microsoft-related files/keys/values will be restored. If this malware/grayware also deleted registry keys/values related to programs that are not from Microsoft, please reinstall those programs on your computer.

    • %User Profile%\Application Data\Microsoft

Step 9

Restore this file from backup only Microsoft-related files will be restored. If this malware/grayware also deleted files related to programs that are not from Microsoft, please reinstall those programs on you computer again.

  • %User Temp%\nsa1.tmp
  • %User Temp%\9F0A~1.EXE


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