BKDR_WINNTI.OWNB

September 01, 2015
 Analysis by: Sammy Chua
 ALIASES:

Trojan.Win32.Kriskynote.bg (Kaspersky); Backdoor.Win32.Winnti.gl(Kaspersky); Trojan:Win32/Raizy.A (Microsoft);Troj/Raizy-A (Sophos);

 PLATFORM:

Windows

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Downloaded from the Internet, Dropped by other malware

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. It arrives as a component bundled with malware/grayware packages.

It does not have any propagation routine.

It executes commands from a remote malicious user, effectively compromising the affected system.

  TECHNICAL DETAILS

File Size:

467,468 bytes

File Type:

DLL

Memory Resident:

Yes

Initial Samples Received Date:

11 Aug 2015

Payload:

Drops files

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.

It arrives as a component bundled with malware/grayware packages.

Installation

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

  • %System%\wmm2.dll
  • %User Temp%\tmp{random}.tmp - is deleted when the system reboots

(Note: %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.. %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)

It drops the following files:

  • %Temp%\deskcpl.tff - contains date/time information, process name and process id of the process that injects code into svchost.exe, process id of the injected svchost.exe, status of code injection (sucess or fail)

(Note: %Temp% is the Windows temporary folder, where it usually is C:\Windows\Temp on all Windows operating system versions.)

It adds the following processes:

  • %System%\sysprep\sysprep.exe

(Note: %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.)

It adds the following mutexes to ensure that only one of its copies runs at any one time:

  • Global\3625989615E3806C118A76FAAC1AE93B
  • Global\Notify_Event_{3ec05b4a-ea88-1378-3389-66706ba27600}
  • Global\59C4D43D3C135DAA2C40390C1FD370F2-{process id}

It injects codes into the following process(es):

  • explorer.exe
  • services.exe
  • the svchost.exe with "netsvcs" as parameter

Autostart Technique

This Trojan starts the following services:

  • {service name}

It creates the following service using its DLL component:

  • Service Name: {service name}
  • Display Name: "Device Wmm Services"
  • Binary Path Name: "%SystemRoot%\System32\svchost.exe -k netsvcs"

Other System Modifications

This Trojan adds the following registry keys:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\{service name}

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\{service name}\Parameters

It adds the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\{service name}
Description = "Monitoring of Hardwares And Automatically Updates The Device Drivers."

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\{service name}\Parameters
ServiceDll = "%System%\wmm2.dll"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\{service name}\Parameters
ServiceMain = "sqlite3_get_error"

It modifies the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\IpFilterDriver
Start = "2"

(Note: The default value data of the said registry entry is "3".)

Propagation

This Trojan does not have any propagation routine.

Backdoor Routine

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

  • arbitrary commands

Other Details

This Trojan requires the following additional components to properly run:

  • %System%\wmm2.dat -> also detected as BKDR_WINNTI.OWNB

(Note: %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.)

It does the following:

  • It starts the IpFilterDriver
  • It lists all services and description to check if the service "Device Wmm Services" is already installed
  • It may delete the following files: %system%\winmm.update, %system%\wmm2.dat and %system%\wmm2.dll
  • It drops a copy of itself as %system%\wmm2.dll
  • It copies the filetime of %system%\cmd.exe to %system%\wmm2.dat and %system%\wmm2.dll
  • It reads %System%\winmm.update to get a updated copy of the component %System%\wmm2.dat
  • It deletes one of the following files depending on the operating system: %System%\sysprep\oleacc.dll, %System%\sysprep\cryptsp.dll or %System%\sysprep\cryptbase.dll
  • It reads the first entry of "netsvcs" key in SOFTWARE\Microsoft\Windows NT\CurrentVersion\Svchost to use it as {service name}

(Note: %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.)

NOTES:
The content of the component file may have already been overwritten.

  SOLUTION

Minimum Scan Engine:

9.750

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

Note that not all files, folders, and registry keys and entries are installed on your computer during this malware's/spyware's/grayware's execution. This may be due to incomplete installation or other operating system conditions. If you do not find the same files/folders/registry information, please proceed to the next step.

Step 3

Scan your computer with your Trend Micro product and note files detected as BKDR_WINNTI.OWNB

Step 4

Restart in Safe Mode

[ Learn More ]

Step 5

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\SYSTEM\CurrentControlSet\Services\{service name}
    • Description = "Monitoring of Hardwares And Automatically Updates The Device Drivers."
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\{service name}\Parameters
    • ServiceDll = "%System%\wmm2.dll"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\{service name}\Parameters
    • ServiceMain = "sqlite3_get_error"

Step 6

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_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\{service name}
    • HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\{service name}\Parameters

Step 7

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_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\IpFilterDriver
    • From: Start = "2"
      To: Start = "3"

Step 8

Search and delete the files detected as BKDR_WINNTI.OWNB

*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 File name* 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.
    *Note: The file name input box title varies depending on the Windows version (e.g. Search for files or folders named or All or part of the file name.).

For Windows Vista, Windows 7, Windows Server 2008, Windows 8, Windows 8.1, and Windows Server 2012 (R2):

  1. Open a Windows Explorer window.
    • For Windows Vista, 7, and Server 2008 users, click Start>Computer.
    • For Windows 8, 8.1, and Server 2012 users, right-click on the lower left corner of the screen,then click File Explorer.
  2. In the Search Computer/This PC input box, type the name of the file that was detected earlier.
  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.

Step 9

Search and delete this file

[ 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.
  • %System%\wmm2.dll
  • %System%\wmm2.dat
  • %User Temp%\tmp{random}.tmp
  • %Temp%\deskcpl.tff
  • %system%\winmm.update

Step 10

Restart in normal mode and scan your computer with your Trend Micro product for files detected as BKDR_WINNTI.OWNB. 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 11

Scan your computer with your Trend Micro product to delete files detected as BKDR_WINNTI.OWNB. 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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