Analysis by: Ryan Paolo Maglaque

 PLATFORM:

Windows

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

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel: Dropped by other malware, Downloaded from the Internet

This information stealing malware was one of the IoCs found in recent attacks targeting hospitals in Israel. This malware is also notable for its stealth. It terminates itself after detecting anti-virus products, script file names, analysis, forensics, and debugging tools, as well as sandboxes and virtual machines.

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 executes commands from a remote malicious user, effectively compromising the affected system.

It steals system information. It retrieves specific information from the affected system. It logs a user's keystrokes to steal information.

  TECHNICAL DETAILS

File Size: 799,980 bytes
File Type: AU3
Memory Resident: No
Initial Samples Received Date: 27 Jun 2017
Payload: Steals information, Drops files, Downloads files, Collects system information, Logs keystrokes

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 component file(s):

  • C:\WinddowsUpdateCheck\WinddowsUpdater.zip

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

  • C:\WinddowsUpdateCheck\WinddowsUpdater.exe

It creates the following folders:

  • C:\WinddowsUpdateCheck

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
WinddowsUpdater = "C:\WinddowsUpdater\WinddowsUpdater.exe C:\WinddowsUpdater\WinddowsUpdater.zip"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
WinddowsUpdate = "C:\WinddowsUpdater\WinddowsUpdater.exe C:\WinddowsUpdater\WinddowsUpdater.zip"

HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows\CurrentVersion\Run
WinddowsUpdater = "C:\WinddowsUpdater\WinddowsUpdater.exe C:\WinddowsUpdater\WinddowsUpdater.zip"

HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows\CurrentVersion\Run
WinddowsUpdate = "C:\WinddowsUpdater\WinddowsUpdater.exe C:\WinddowsUpdater\WinddowsUpdater.zip"

It drops the following file(s) in the Windows Common Startup folder to enable its automatic execution at every system startup:

  • %User Startup%\WinddowsUpdater.lnk

(Note: %User Startup% is the current user's Startup folder, which is usually C:\Documents and Settings\{user}\Start Menu\Programs\Startup on Windows 2000 and XP, and C:\Documents and Settings\{User name}\Start Menu\Programs\Startup on Windows Vista, 7, and 8.)

Other System Modifications

This Worm deletes the following files:

  • %User Startup%\AntiWormUpdate.lnk
  • %User Startup%\AntiUsbWormUpdate.lnk

(Note: %User Startup% is the current user's Startup folder, which is usually C:\Documents and Settings\{user}\Start Menu\Programs\Startup on Windows 2000 and XP, and C:\Documents and Settings\{User name}\Start Menu\Programs\Startup on Windows Vista, 7, and 8.)

It adds the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
ShowSuperHidden = 0

Backdoor Routine

This Worm executes the following commands from a remote malicious user:

  • Download files
  • Connect to URLs
  • Open a cmd to execute commands
  • Install a keylogger
  • Take a screenshot
  • Extract password from browsers(Firefox, Opera, Chrome)
  • Process start, terminate, restart

It connects to the following URL(s) to send and receive commands from a remote malicious user:

  • http://{BLOCKED}stineop.com/myblog/user
  • {BLOCKED}othere.publicvm.com
  • {BLOCKED}016.linkpc.net
  • {BLOCKED}016.publicvm.com
  • {BLOCKED}al.publicvm.com
  • {time-based hash}.linkpc.net
  • {time-based hash}.ddns.net
  • {time-based hash}.no-ip.info
  • {time-based hash}.no-ip.biz
  • {time-based hash}.zapto.org
  • {time-based hash}.publicvm.com

Dropping Routine

This Worm drops the following file(s), which it uses for its keylogging routine:

  • C:\WinddowsUpdateCheck\__.BIN

Information Theft

This Worm steals system information.

It retrieves the following information from the affected system:

  • Information from browser (Chrome, Opera, Firefox)
  • OS Version
  • OS Architecture
  • OS Service Pack
  • Computer name
  • Username
  • Country Code
  • Installed Antivirus product

It logs a user's keystrokes to steal information.

NOTES:

Anti-analysis Techniques

It checks the existence of AV products and analysis tools:

  • avp.exe
  • zonealarm.exe
  • avguard.exe
  • tcpview.exe
  • procmon.exe
  • nod32kui.exe
  • kavmm.exe
  • procmon.exe
  • fsbwsys.exe
  • vmacthlp.exe
  • avp.exe
  • Kavsvc.exe
  • snxhk.dll
  • tracer.dll
  • SbieDll.dll
  • api_log.dll
  • dir_watch.dll
  • dbghelp.dll
  • monitornet.dll
  • cuckoo
  • SandCastle
  • sandbox
  • tracer.dll
  • tracer.dll
It checks if the following processes related to sandbox exists:
  • BehaviorDumper.exe
  • FakeHTTPServer.exe
  • FakeServer.exe
  • FortiTracer.exe
  • SbieSvc.exe
  • VBoxService.exe
  • VBoxTray.exe
  • VMwareService.exe
  • VMwareUser.exe
  • guninraik.exe
  • vmtoolsd.exe

Checks script filenames if containing the strings below, and must not have length greater than 35:

  • "artifact"
  • "sample"
  • "."

Checks folder where it is being executed:

  • "C:\virus"
  • "C:\"

Checks if the following folders exist:

  • "C:\CWSandbox\"
  • "C:\Python26\"
  • "C:\cuckoo\"

Checks Virtual Machines:

  • "Bochs"
  • "VirtualBox"
  • "innotek"
  • "VMware"

If any of the above are confirmed, the script will not continue.

Propagation

It drops copies of itself in all drives:

  • {drive}\WinddowsUpdateCheck\WinddowsUpdater.exe
  • {drive}\WinddowsUpdateCheck\WinddowsUpdater.zip

It drops the following shortcut files in all removable drives:

  • {Drive}\My Pictures.lnk
  • {Drive}\My Videos.lnk
  • {Drive}\My Downloads.lnk

It also drops copies of itself inside the existing folders on removable drives

  • {Drive}\{folder name}\Games.lnk
  • {Drive}\{folder name}\Downloads.lnk
  • {Drive}\{folder name}\{folder name}.lnk

Backdoor Commands

It is capable of the following commands:

  • download_file ← download and execute files
  • download_a3x ← download and execute autoit script
  • msgbox ← display msgbox
  • url ← visit url
  • cmd ← execute command shell
  • GoTorat ← execute RAT commands

If the backdoor command contains "GoTorat", it may perform the following commands:

  • FILE_MANAGER_DOWNLOAD
  • SCREEN_SHUT_INIT
  • SCREEN_SHUT_STOP
  • KEYLOGGER_INIT
  • KEYLOGGER_STOP
  • PASSWORD_INIT
  • PASSWORD_STOP
  • FILE_MANAGER_ROOT
  • FILE_MANAGER_STOP
  • SCREEN_THUMB
  • MISC_INIT
  • MISC_STOP
  • RUN_SIMPLE_DISK
  • RUN_SIMPLE_URL
  • RUN_SCRIPT_DISK
  • RUN_SCRIPT_URL

If the backdoor command contains "radbot", it may perform the following commands:

  • GETINFO
  • SLEEP
  • EXIT
  • RECONNECT
  • MSGBOX
  • URL
  • CMD
  • UPDATEE
  • DOWNLOAD
  • SHUTDOWN
  • RESTART
  • LOGOFF
  • STANDBY

It checks for the presence of the following files:

  • C:\WinddowsUpdateCheck\ebay.lnk
  • C:\WinddowsUpdateCheck\hamazon.lnk
  • C:\WinddowsUpdateCheck\hebay.lnk
  • C:\WinddowsUpdateCheck\hmoneygram.lnk
  • C:\WinddowsUpdateCheck\hpaypal.lnk
  • C:\WinddowsUpdateCheck\hpayza.lnk
  • C:\WinddowsUpdateCheck\hskrill.lnk
  • C:\WinddowsUpdateCheck\hukash.lnk
  • C:\WinddowsUpdateCheck\hwestern union.lnk
  • C:\WinddowsUpdateCheck\moneygram.lnk
  • C:\WinddowsUpdateCheck\paypal.lnk
  • C:\WinddowsUpdateCheck\skrill.lnk
  • C:\WinddowsUpdateCheck\ukash.lnk
  • C:\WinddowsUpdateCheck\western union.lnk

  SOLUTION

Minimum Scan Engine: 9.850
FIRST VSAPI PATTERN FILE: 13.500.09
FIRST VSAPI PATTERN DATE: 28 Jun 2017
VSAPI OPR PATTERN File: 13.501.00
VSAPI OPR PATTERN Date: 29 Jun 2017

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

Note that not all files, folders, and registry keys and entries are installed on your computer during this malware's/spyware's/grayware's execution. This may be due to incomplete installation or other operating system conditions. If you do not find the same files/folders/registry information, please proceed to the next step.

Step 3

Identify and terminate files detected as WORM_RETADUP.A

[ Learn More ]
  1. Windows Task Manager may not display all running processes. In this case, please use a third-party process viewer, preferably Process Explorer, to terminate the malware/grayware/spyware file. You may download the said tool here.
  2. If the detected file is displayed in either Windows Task Manager or Process Explorer but you cannot delete it, restart your computer in safe mode. To do this, refer to this link for the complete steps.
  3. If the detected file is not displayed in either Windows Task Manager or Process Explorer, continue doing the next steps.

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
    • WinddowsUpdater = "C:\WinddowsUpdater\WinddowsUpdater.exe C:\WinddowsUpdater\WinddowsUpdater.zip"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • WinddowsUpdate = "C:\WinddowsUpdater\WinddowsUpdater.exe C:\WinddowsUpdater\WinddowsUpdater.zip"
  • In HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run
    • WinddowsUpdater = "C:\WinddowsUpdater\WinddowsUpdater.exe C:\WinddowsUpdater\WinddowsUpdater.zip"
  • In HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run
    • WinddowsUpdate = "C:\WinddowsUpdater\WinddowsUpdater.exe C:\WinddowsUpdater\WinddowsUpdater.zip"

Step 5

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.
C:\WinddowsUpdateCheck\
{drive}\WinddowsUpdateCheck\

Step 6

Search and delete this file

[ Learn More ]
There may be some 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.
{Drive}\My Pictures.lnk
{Drive}\My Videos.lnk
{Drive}\My Downloads.lnk
{Drive}\{folder name}\Games.lnk
{Drive}\{folder name}\Downloads.lnk
{Drive}\{folder name}\{folder name}.lnk
%User Startup%\WinddowsUpdater.lnk
C:\WinddowsUpdateCheck\__.BIN

Step 7

Scan your computer with your Trend Micro product to delete files detected as WORM_RETADUP.A. 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 Startup%\AntiWormUpdate.lnk
%User Startup%\AntiUsbWormUpdate.lnk


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