WORM_NGRBOT.AU


 ALIASES:

Worm:Win32/Dorkbot.A (Microsoft); PWS-Zbot.gen.ke (McAfee); W32.IRCBot.NG (Symantec); Worm.Win32.Ngrbot.gym (Kaspersky); Trojan.Win32.Generic!BT (Sunbelt); Trojan.Generic.6901143 (FSecure)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

This worm 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:

208,896 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

08 Dec 2011

Arrival Details

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

  • %User Profile%\Application Data\Zbigif.exe

(Note: %User Profile% is the current user's profile folder, which is usually C:\Windows\Profiles\{user name} on Windows 98 and ME, C:\WINNT\Profiles\{user name} on Windows NT, and C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003.)

It creates the following folders:

  • %User Profile%\Application Data\VMware
  • %User Profile%\Microsoft\Dr Watson
  • %System Root%\Documents and Settings
  • %System Root%\Documents and Settings\Administrator
  • %Start Menu%\Programs
  • %User Profile%\Application Data
  • %User Profile%\Application Data\kakao3

(Note: %User Profile% is the current user's profile folder, which is usually C:\Windows\Profiles\{user name} on Windows 98 and ME, C:\WINNT\Profiles\{user name} on Windows NT, and C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003.. %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.. %Start Menu% is the current user's Start Menu folder, which is usually C:\Windows\Profiles\{user name}\Start Menu on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Start Menu on Windows NT and C:\Windows\Start Menu or C:\Documents and Settings\{User name}\Start Menu on Windows 2000, XP, and Server 2003.)

Autostart Technique

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
Zbigif = "%User Profile%\Application Data\Zbigif.exe"

Other System Modifications

This worm deletes the following files:

  • %User Profile%\Application Data\1.tmp
  • %User Profile%\Application Data\2.tmp

(Note: %User Profile% is the current user's profile folder, which is usually C:\Windows\Profiles\{user name} on Windows 98 and ME, C:\WINNT\Profiles\{user name} on Windows NT, and C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003.)

It adds the following registry keys:

HKEY_CURRENT_USER\Software\WinRAR SFX

It adds the following registry entries:

HKEY_CURRENT_USER\Software\WinRAR SFX
C%%Documents and Settings%Administrator%Start Menu%Programs%Startup = "%User Startup%"

HKEY_CURRENT_USER\Software\WinRAR SFX
C%%Documents and Settings%Administrator%Application Data%kakao3 = {random characters}

It modifies the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
DrWatson
NumberOfCrashes = 1

(Note: The default value data of the said registry entry is 0.)

It deletes the following registry keys:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
PCHealth\ErrorReporting\DW

Dropping Routine

This worm drops the following files:

  • %User Profile%\Application Data\1.exe
  • %User Profile%\Application Data\2.exe
  • %User Profile%\Application Data\3.tmp
  • %User Profile%\Dr Watson\drwtsn32.log
  • %User Profile%\Dr Watson\user.dmp
  • __tmp_rar_sfx_access_check_74781
  • newmoon17.exe
  • __tmp_rar_sfx_access_check_77875
  • fuckHDZSDP.exe
  • new.exe

(Note: %User Profile% is the current user's profile folder, which is usually C:\Windows\Profiles\{user name} on Windows 98 and ME, C:\WINNT\Profiles\{user name} on Windows NT, and C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003.)

Other Details

This worm connects to the following possibly malicious URL:

  • http://api.{BLOCKED}ia.com/
  • http://img105.{BLOCKED}h.com/2011/11/11/751748664.gif
  • http://img103.{BLOCKED}h.com/2011/11/14/477334673.gif
  • http://img103.{BLOCKED}h.com/2011/11/14/955459483.gif

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine:

9.200

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

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
    • WinRAR SFX

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_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • Zbigif="%User Profile%\Application Data\Zbigif.exe"
  • In HKEY_CURRENT_USER\Software\WinRAR SFX
    • C%%Documents and Settings%Administrator%Start Menu%Programs%Startup="%User Startup%"
  • In HKEY_CURRENT_USER\Software\WinRAR SFX
    • C%%Documents and Settings%Administrator%Application Data%kakao3={random characters}

Step 5

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\DrWatson
    • From: NumberOfCrashes=1
      To: NumberOfCrashes=0

Step 6

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.
  • %User Profile%\Application Data\VMware
  • %User Profile%\Microsoft\Dr Watson
  • %System Root%\Documents and Settings
  • %System Root%\Documents and Settings\Administrator
  • %Start Menu%\Programs
  • %User Profile%\Application Data
  • %User Profile%\Application Data\kakao3

Step 7

Search and delete these files

[ Learn More ]
There may be some component 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.
  • %User Profile%\Application Data\1.exe
  • %User Profile%\Application Data\2.exe
  • %User Profile%\Application Data\3.tmp
  • %User Profile%\Dr Watson\drwtsn32.log
  • %User Profile%\Dr Watson\user.dmp
  • __tmp_rar_sfx_access_check_74781
  • newmoon17.exe
  • __tmp_rar_sfx_access_check_77875
  • fuckHDZSDP.exe
  • new.exe

Step 8

Restart in normal mode and scan your computer with your Trend Micro product for files detected as WORM_NGRBOT.AU. 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 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 Profile%\Application Data\1.tmp
  • %User Profile%\Application Data\2.tmp

Step 10

Restore these deleted registry keys/values from backup

*Note: Only Microsoft-related keys/values will be restored. If the malware/grayware also deleted registry keys/values related to programs that are not from Microsoft, please reinstall those programs on your computer.

  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\PCHealth\ErrorReporting
    • DW


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