ALIASES:

DDoS:Win32/Nitol.B (Microsoft); RDN/Generic PWS.y (McAfee); Trojan-PSW.Win32.Fareit.bcnq (Kaspersky); Trojan.Win32.Generic!BT (Sunbelt); Trojan horse Zbot.AFHX (AVG)

 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: 311,808 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 07 Aug 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:

  • %User Temp%\IXP000.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.)

Autostart Technique

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

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\RunOnce
wextract_cleanup0 = "rundll32.exe %System%\advpack.dll,DelNodeRunDLL32 %User Temp%\IXP000.TMP\ "

Other System Modifications

This Trojan adds the following registry keys:

HKEY_CURRENT_USER\Software\Local AppWizard-Generated Applications

HKEY_CURRENT_USER\Software\Local AppWizard-Generated Applications\
ImgSeg

HKEY_CURRENT_USER\Software\Local AppWizard-Generated Applications\
ImgSeg\Recent File List

HKEY_CURRENT_USER\Software\Local AppWizard-Generated Applications\
ImgSeg\Settings

HKEY_CURRENT_USER\Software\WinRAR

It adds the following registry entries:

HKEY_CURRENT_USER\Software\WinRAR
HWID = "{random values}"

HKEY_CURRENT_USER\Software\WinRAR
Client Hash = "{random values}"

Dropping Routine

This Trojan drops the following files:

  • %User Temp%\IXP000.TMP\TMP4351$.TMP
  • %User Temp%\IXP000.TMP\5.scr
  • %User Temp%\IXP000.TMP\5.sc_
  • %Application Data%\CSIDL_
  • %Application Data%\CSIDL_X
  • %Start Menu%\Programs\Startupx\system.pif

(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.. %Application Data% is the Application Data folder, where it usually is C:\Documents and Settings\{user name}\Application Data on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Roaming 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.. %Start Menu% is the Start Menu folder, where it usually is C:\Documents and Settings\{user name}\Start Menu on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Roaming\Microsoft\Windows\Start Menu 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.)

Other Details

This Trojan connects to the following possibly malicious URL:

  • {BLOCKED}0.24.244

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

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
    • Local AppWizard-Generated Applications
  • In HKEY_CURRENT_USER\Software\Local AppWizard-Generated Applications
    • ImgSeg
  • In HKEY_CURRENT_USER\Software\Local AppWizard-Generated Applications\ImgSeg
    • Recent File List
  • In HKEY_CURRENT_USER\Software\Local AppWizard-Generated Applications\ImgSeg
    • Settings
  • In HKEY_CURRENT_USER\Software
    • WinRAR

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_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\RunOnce
    • wextract_cleanup0 = "rundll32.exe %System%\advpack.dll,DelNodeRunDLL32 %User Temp%\IXP000.TMP\ "
  • In HKEY_CURRENT_USER\Software\WinRAR
    • HWID = "{random values}"
  • In HKEY_CURRENT_USER\Software\WinRAR
    • Client Hash = "{random values}"

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%\IXP000.TMP\TMP4351$.TMP
  • %User Temp%\IXP000.TMP\5.scr
  • %User Temp%\IXP000.TMP\5.sc_
  • %Application Data%\CSIDL_
  • %Application Data%\CSIDL_X
  • %Start Menu%\Programs\Startupx\system.pif

Step 6

Search and delete this folder

[ 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.
  • %User Temp%\IXP000.TMP

Step 7

Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_NITOL.DUKMH. 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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