PLATFORM:

Windows

 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: 4,179,474 bytes
File Type: EXE
Memory Resident: No
Initial Samples Received Date: 11 Sep 2015

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%\Documents and Settings\Wilbert
  • %User Profile%\Application Data\Windows
  • %User Profile%\Windows\control
  • %User Temp%\8.tmp
  • %Program Files% (x86)\AIMP4
  • %Program Files% (x86)

(Note: %System Root% is the Windows root folder, where it usually is C:\ on all Windows operating system versions.. %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.. %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.. %Program Files% is the Program Files folder, where it usually is C:\Program Files on all Windows operating system versions; C:\Program Files (x86) for 32-bit applications running on Windows 64-bit operating systems.)

Other System Modifications

This Trojan deletes the following files:

  • %User Temp%\8.tmp
  • %User Temp%\C.tmp

(Note: %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 adds the following registry keys:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon\
Notify\RWLN

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Control\SafeBoot\Network\
RManService

HKEY_LOCAL_MACHINE\SYSTEM\Remote Manipulator System

HKEY_LOCAL_MACHINE\SYSTEM\Remote Manipulator System\
v4

HKEY_LOCAL_MACHINE\SYSTEM\Remote Manipulator System\
v4\Server

HKEY_LOCAL_MACHINE\SYSTEM\Remote Manipulator System\
v4\Server\Parameters

It adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon\
Notify\RWLN
Asynchronous = "0"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon\
Notify\RWLN
Impersonate = "0"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon\
Notify\RWLN
DllName = "RWLN.dll"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon\
Notify\RWLN
Logoff = "WLEventLogoff"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon\
Notify\RWLN
Logon = "WLEventLogon"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon\
Notify\RWLN
Startup = "WLEventStartup"

HKEY_LOCAL_MACHINE\SYSTEM\Remote Manipulator System\
v4\Server\Parameters
Options = "{random values}"

HKEY_LOCAL_MACHINE\SYSTEM\Remote Manipulator System\
v4\Server\Parameters
InternetId = "{random values}"

HKEY_LOCAL_MACHINE\SYSTEM\Remote Manipulator System\
v4\Server\Parameters
Password = "{random values}"

HKEY_LOCAL_MACHINE\SYSTEM\Remote Manipulator System\
v4\Server\Parameters
UserAccess = "{random values}"

HKEY_LOCAL_MACHINE\SYSTEM\Remote Manipulator System\
v4\Server\Parameters
FUSClientPath = "%Program Files% (x86)\AIMP4\rfusclient.exe"

HKEY_LOCAL_MACHINE\SYSTEM\Remote Manipulator System\
v4\Server\Parameters
CalendarRecordSettings = "{random values}"

Dropping Routine

This Trojan drops the following files:

  • __tmp_rar_sfx_access_check_229468
  • run.exe
  • data.exe
  • regedit.reg
  • __tmp_rar_sfx_access_check_235296
  • rutserv.exe
  • start.vbs
  • vp8decoder.dll
  • vp8encoder.dll
  • install.bat
  • rfusclient.exe
  • %Program Files% (x86)\AIMP4\rfusclient.exe
  • %Program Files% (x86)\AIMP4\rutserv.exe
  • %Program Files% (x86)\AIMP4\vp8decoder.dll
  • %Program Files% (x86)\AIMP4\vp8encoder.dll
  • %Program Files% (x86)\AIMP4\regedit.reg
  • %System%\RWLN.dll

(Note: %Program Files% is the Program Files folder, where it usually is C:\Program Files on all Windows operating system versions; C:\Program Files (x86) for 32-bit applications running on Windows 64-bit operating systems.. %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.)

Other Details

This Trojan connects to the following possibly malicious URL:

  • {BLOCKED}4.156.179

This report is generated via an automated analysis system.

  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

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\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon\Notify
    • RWLN
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SafeBoot\Network
    • RManService
  • In HKEY_LOCAL_MACHINE\SYSTEM
    • Remote Manipulator System
  • In HKEY_LOCAL_MACHINE\SYSTEM\Remote Manipulator System
    • v4
  • In HKEY_LOCAL_MACHINE\SYSTEM\Remote Manipulator System\v4
    • Server
  • In HKEY_LOCAL_MACHINE\SYSTEM\Remote Manipulator System\v4\Server
    • Parameters

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 NT\CurrentVersion\Winlogon\Notify\RWLN
    • Asynchronous = "0"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon\Notify\RWLN
    • Impersonate = "0"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon\Notify\RWLN
    • DllName = "RWLN.dll"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon\Notify\RWLN
    • Logoff = "WLEventLogoff"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon\Notify\RWLN
    • Logon = "WLEventLogon"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon\Notify\RWLN
    • Startup = "WLEventStartup"
  • In HKEY_LOCAL_MACHINE\SYSTEM\Remote Manipulator System\v4\Server\Parameters
    • Options = "{random values}"
  • In HKEY_LOCAL_MACHINE\SYSTEM\Remote Manipulator System\v4\Server\Parameters
    • InternetId = "{random values}"
  • In HKEY_LOCAL_MACHINE\SYSTEM\Remote Manipulator System\v4\Server\Parameters
    • Password = "{random values}"
  • In HKEY_LOCAL_MACHINE\SYSTEM\Remote Manipulator System\v4\Server\Parameters
    • UserAccess = "{random values}"
  • In HKEY_LOCAL_MACHINE\SYSTEM\Remote Manipulator System\v4\Server\Parameters
    • FUSClientPath = "%Program Files% (x86)\AIMP4\rfusclient.exe"
  • In HKEY_LOCAL_MACHINE\SYSTEM\Remote Manipulator System\v4\Server\Parameters
    • CalendarRecordSettings = "{random values}"

Step 4

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.
  • __tmp_rar_sfx_access_check_229468
  • run.exe
  • data.exe
  • regedit.reg
  • __tmp_rar_sfx_access_check_235296
  • rutserv.exe
  • start.vbs
  • vp8decoder.dll
  • vp8encoder.dll
  • install.bat
  • rfusclient.exe
  • %Program Files% (x86)\AIMP4\rfusclient.exe
  • %Program Files% (x86)\AIMP4\rutserv.exe
  • %Program Files% (x86)\AIMP4\vp8decoder.dll
  • %Program Files% (x86)\AIMP4\vp8encoder.dll
  • %Program Files% (x86)\AIMP4\regedit.reg
  • %System%\RWLN.dll

Step 5

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%\Documents and Settings\Wilbert
  • %User Profile%\Application Data\Windows
  • %User Profile%\Windows\control
  • %User Temp%\8.tmp
  • %Program Files% (x86)\AIMP4
  • %Program Files% (x86)

Step 6

Scan your computer with your Trend Micro product to delete files detected as TROJ_RECONYC.WEZ. 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

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%\8.tmp
  • %User Temp%\C.tmp


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