TROJ_AGENT.BEKB
Backdoor:Win32/Jukbot.B (Microsoft); Suspicious.MH690 (Symantec)
Windows 2000, Windows XP, Windows Server 2003
![](/vinfo/imgFiles/legend.jpg)
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
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
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
Step 3
Delete this registry key
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
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
- %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
- %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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