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WORM_DORKBOT.XYV

April 24, 2014
 ALIASES:

Worm:Win32/Dorkbot.I (Microsoft); PWS-Zbot-FBDR!1949AD832856 (McAfee); Worm.Win32.Dorkbot.aq (Kaspersky); Mal/EncPk-AKC (Sophos); Trojan.Win32.Zbot.fdm (v) (Sunbelt); Trojan horse SHeur4.BKNO (AVG)

 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.

It deletes itself after execution.

  TECHNICAL DETAILS

File Size:

141,824 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

24 Apr 2014

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\temp.bin
  • %User Profile%\Application Data\ScreenSaverPro.scr
  • %User Profile%\Microsoft\Errare.exe

(Note: %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.)

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
Screen Saver Pro 3.1 = "%User Profile%\Application Data\ScreenSaverPro.scr"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
Errare = "%User Profile%\Microsoft\Errare.exe"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
Trrart = "%User Profile%\Microsoft\Trrart.exe"

Other System Modifications

This worm modifies the following file(s):

  • %Windows%\wiadebug.log

(Note: %Windows% is the Windows folder, which is usually C:\Windows.)

It deletes the following files:

  • %User Profile%\Application Data\temp.bin
  • %User Profile%\Application Data\ScreenSaverPro.scr
  • %User Temp%\wipmania.com
  • %User Profile%\Application Data\37.tmp
  • %Windows%\SoftwareDistribution\DataStore\Logs\edbtmp.log
  • 37.exe.gonewiththewings

It adds the following registry keys:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Applets\
Paint

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Applets\
Paint\Recent File List

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Applets\
Paint\Settings

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Applets\
Paint\View

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Applets\
Paint\Text

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Applets\
Paint\Colors

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Applets\
Paint\General-Summary

Dropping Routine

This worm drops the following files:

  • %User Profile%\Application Data\37.exe
  • %User Profile%\Application Data\temp.bin
  • %User Profile%\Application Data\ScreenSaverPro.scr

(Note: %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.)

Other Details

This worm connects to the following possibly malicious URL:

  • http://app.{BLOCKED}ia.net/icon/n.api
  • http://api.{BLOCKED}ia.com
  • http://{BLOCKED}.78.239/6521.exe
  • http://{BLOCKED}5.246.160/6521.exe
  • http://{BLOCKED}5.246.218/av.txt

It deletes itself after execution.

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine:

9.300

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\Microsoft\Windows\CurrentVersion\Applets
    • Paint
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Applets\Paint
    • Recent File List
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Applets\Paint
    • Settings
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Applets\Paint
    • View
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Applets\Paint
    • Text
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Applets\Paint
    • Colors
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Applets\Paint
    • General-Summary

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
    • Screen Saver Pro 3.1 = "%User Profile%\Application Data\ScreenSaverPro.scr"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • Errare = "%User Profile%\Microsoft\Errare.exe"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • Trrart = "%User Profile%\Microsoft\Trrart.exe"

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 Profile%\Application Data\37.exe
  • %User Profile%\Application Data\temp.bin
  • %User Profile%\Application Data\ScreenSaverPro.scr

Step 6

Restart in normal mode and scan your computer with your Trend Micro product for files detected as WORM_DORKBOT.XYV. 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 deleted/modified files and/or registry entries from backup

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

    • %Windows%\wiadebug.log

Step 8

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\temp.bin
  • %User Profile%\Application Data\ScreenSaverPro.scr
  • %User Temp%\wipmania.com
  • %User Profile%\Application Data\37.tmp
  • %Windows%\SoftwareDistribution\DataStore\Logs\edbtmp.log
  • 37.exe.gonewiththewings


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