WORM_DORKBOT.IEB


 PLATFORM:

Windows

 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:

114,176 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

15 Aug 2015

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\c731200
  • %User Temp%\Adobe\Reader_sl.exe
  • %User Profile%\Identities\Jrrarj.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.. %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 creates the following folders:

  • %User Temp%\Adobe
  • %Program Files%\Common Files\CreativeAudio

(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.. %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.)

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
Adobe System Incorporated = "%User Temp%\Adobe\Reader_sl.exe"

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

Other System Modifications

This worm deletes the following files:

  • %User Profile%\Application Data\c731200
  • %User Profile%\Application Data\ScreenSaverPro.scr
  • %User Profile%\Application Data\temp.bin
  • %User Temp%\Adobe\Reader_sl.exe
  • %User Profile%\Application Data\6.tmp
  • %User Profile%\Application Data\9.tmp
  • %Program Files%\Common Files\CreativeAudio\lgzovlzqe.exe:Zone.Identifier

(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.. %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.)

It adds the following registry keys:

HKEY_CURRENT_USER\Software\Win7zip

HKEY_CURRENT_USER\Software\Classes\
CLSID\{EFFB3E78-7C4C-9643-A73B-BC78F4C3E267}\0E7302EC\
CG1

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Image File Execution Options\
lgzovlzqe.exe

It adds the following registry entries:

HKEY_CURRENT_USER\Software\Win7zip
Uuid = "{random values}"

Dropping Routine

This worm drops the following files:

  • %User Profile%\Application Data\6.exe
  • %User Profile%\Application Data\9.exe
  • %Program Files%\Common Files\CreativeAudio\desktop.ini

(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.. %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 Details

This worm connects to the following possibly malicious URL:

  • http://api.{BLOCKED}ia.com
  • http://{BLOCKED}.255.146/bet9.exe
  • http://{BLOCKED}.255.146/and.exe
  • {BLOCKED}170.190
  • {BLOCKED}69.142

It deletes itself after execution.

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
    • Win7zip
  • In HKEY_CURRENT_USER\Software\Classes\CLSID\{EFFB3E78-7C4C-9643-A73B-BC78F4C3E267}\0E7302EC
    • CG1
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options
    • lgzovlzqe.exe

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
    • Adobe System Incorporated = "%User Temp%\Adobe\Reader_sl.exe"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • Jrrarj = "%User Profile%\Identities\Jrrarj.exe"
  • In HKEY_CURRENT_USER\Software\Win7zip
    • Uuid = "{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 Profile%\Application Data\6.exe
  • %User Profile%\Application Data\9.exe
  • %Program Files%\Common Files\CreativeAudio\desktop.ini

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 Temp%\Adobe
  • %Program Files%\Common Files\CreativeAudio

Step 7

Restart in normal mode and scan your computer with your Trend Micro product for files detected as WORM_DORKBOT.IEB. 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 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\c731200
  • %User Profile%\Application Data\ScreenSaverPro.scr
  • %User Profile%\Application Data\temp.bin
  • %User Temp%\Adobe\Reader_sl.exe
  • %User Profile%\Application Data\6.tmp
  • %User Profile%\Application Data\9.tmp
  • %Program Files%\Common Files\CreativeAudio\lgzovlzqe.exe:Zone.Identifier


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