TROJ_YAKES.JZ

 Modified by: Kathleen Notario

 ALIASES:

Troj/Bredo-RK (Sophos); W32/Yakes.B!tr (Fortinet)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW


This Trojan arrives as an attachment to email messages spammed by other malware/grayware or malicious users.

It deletes the initially executed copy of itself.

  TECHNICAL DETAILS

File Size:

77,312 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

10 Feb 2012

Arrival Details

This Trojan arrives as an attachment to email messages spammed by other malware/grayware or malicious users.

Installation

This Trojan drops and executes the following files:

  • %Program Files%\Trusteer\Rapport\bin\RapportService.exe - also detected as TROJ_YAKES.JZ
  • %System%\RPService.exe - also detected as TROJ_YAKES.JZ

(Note: %Program Files% is the default Program Files folder, usually C:\Program Files.. %System% is the Windows system folder, which is usually C:\Windows\System on Windows 98 and ME, C:\WINNT\System32 on Windows NT and 2000, or C:\Windows\System32 on Windows XP and Server 2003.)

It drops the following copies of itself into the affected system:

  • %System%\{random filename}.exe
  • %User Temp%\{random filename}.exe

(Note: %System% is the Windows system folder, which is usually C:\Windows\System on Windows 98 and ME, C:\WINNT\System32 on Windows NT and 2000, or C:\Windows\System32 on Windows XP and Server 2003.. %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.)

It adds the following processes:

  • svchost.exe

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

  • {user name}-{random}

Autostart Technique

This Trojan modifies the following registry entries to ensure it automatic execution at every system startup:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon
Userinit = "%System%\userinit.exe,%System%\{random filename}.exe"

(Note: The default value data of the said registry entry is %System%\userinit.exe,.)

HKEY_CURRENT_USER\Software\Microsoft\
Windows NT\CurrentVersion\Windows
load = "%User Temp%\{random filename}.exe"

(Note: The default value data of the said registry entry is {blank}.)

Other System Modifications

This Trojan adds the following registry entries:

HKEY_CLASSES_ROOT\MyEze.1\shell\
open\command
(default) = "%System%\RPService.exe %0 %1 %2"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Image File Execution Options\
RapportMgmtService.exe
Debugger = "RPService.exe"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Image File Execution Options\
RapportService.exe
Debugger = "RPService.exe"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Image File Execution Options\
RapportSetup-Full.exe
Debugger = "RPXService.exe"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Image File Execution Options\
RapportSetup.exe
Debugger = "RPXService.exe"

It adds the following registry keys as part of its installation routine:

HKEY_CLASSES_ROOT\.eze

HKEY_CLASSES_ROOT\MyEze.1

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\RapportMgmtService

Other Details

This Trojan deletes the initially executed copy of itself

NOTES:

It connects to the following URL to inform a remote malicious user of its installation:

  • http://{BLOCKED}.{BLOCKED}.94.165/asdfasdgfs/Fiur5sDzx2col.php

It moves the following files/directories:

  • %Program Files%\Trustee\Rapport\bin\RapportService.exe
  • %Program Files%\Trusteer
  • %System Root%\Documents and Settings\All Users\Application Data\Trusteer
  • %System%\drivers\RapportKELL.sys

as follows:

  • %Program Files%\Trustee\Rapport\bin\RapportService.eze
  • %Program Files%\Trustee
  • %System Root%\Documents and Settings\All Users\Application Data\Trustee
  • %System%\drivers\RaportKELL.sys

  SOLUTION

Minimum Scan Engine:

9.200

FIRST VSAPI PATTERN FILE:

8.766.04

FIRST VSAPI PATTERN DATE:

10 Feb 2012

VSAPI OPR PATTERN File:

8.767.00

VSAPI OPR PATTERN Date:

10 Feb 2012

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 delete files detected as TROJ_YAKES.JZ using either the Startup Disk or Recovery Console

[ Learn More ]

Step 3

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\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon
    • From: Userinit = "%System%\userinit.exe,%System%\{random filename}.exe"
      To: Userinit = "%System%\userinit.exe,"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\Windows
    • From: load = "%User Temp%\{random filename}.exe"
      To: load = "{blank}"

Step 4

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. Before you could do this, you must restart in Safe Mode. For instructions on how to do this, you may refer to this page If the preceding step requires you to restart in safe mode, you may proceed to edit the system registry.

  • In HKEY_CLASSES_ROOT
    • .eze
  • In HKEY_CLASSES_ROOT
    • MyEze.1
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services
    • RapportMgmtService

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\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\RapportMgmtService.exe
    • Debugger = "RPService.exe"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\RapportService.exe
    • Debugger = "RPService.exe"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\RapportSetup-Full.exe
    • Debugger = "RPXService.exe"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\RapportSetup.exe
    • Debugger = "RPXService.exe"

Step 6

Scan your computer with your Trend Micro product to delete files detected as TROJ_YAKES.JZ. 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.

NOTES:

To Restore Renamed Files:

  1. Search for the following files:
    • %Program Files%\Trustee
    • %Program Files%\Trustee\Rapport\bin\RapportService.eze
    • %System Root%\Documents and Settings\All Users\Application Data\Trustee
    • %System%\drivers\RaportKELL.sys
  2. Rename these files as follows:
    • %Program Files%\Trustee\Rapport\bin\RapportService.exe
    • %Program Files%\Trusteer
    • %System Root%\Documents and Settings\All Users\Application Data\Trusteer
    • %System%\drivers\RapportKELL.sys


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