Worm.Win32.DORKBOT.TIGAAAR

 Analysis by: Carl Maverick Pascual

 ALIASES:

Trojan.Win32.Zonidel.elr (Kaspersky) ; W32/Zonidel.ELR!tr (Fortinet)

 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 drops copies of itself in all removable drives.

  TECHNICAL DETAILS

File Size:

327,680 bytes

File Type:

EXE

Initial Samples Received Date:

25 Jul 2019

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 adds the following folders:

  • {Removable Drive}:\__

It drops the following files:

  • %Application Data%\winsvcs.txt
  • {Removable Drive}:\.lnk

(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Roaming on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).)

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

  • {Removable Drive}:\__\DriveMgr.exe
  • %Windows%\2032827881\sysyrxs.exe

(Note: %Windows% is the Windows folder, where it usually is C:\Windows on all Windows operating system versions.)

It adds the following processes:

  • %Windows%\2032827881\sysyxrs.exe

(Note: %Windows% is the Windows folder, where it usually is C:\Windows on all Windows operating system versions.)

Autostart Technique

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

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
Microsoft Windows Driver = %Windows%\2032827881\sysyrxs.exe

HKEY_CURRENT_USER\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
Microsoft Windows Driver = %Windows%\2032827881\sysyrxs.exe

Other System Modifications

This Worm also creates the following registry entry(ies) as part of its installation routine:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center
AntiVirusOverride = 1

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

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center
UpdatesOverride = 1

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

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center
FirewallOverride = 1

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

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center
AntiVirusDisableNotify = 1

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

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center
UpdatesDisableNotify = 1

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

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center
AutoUpdateDisableNotify = 1

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

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center
FirewallDisableNotify = 1

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

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center
DisableSR = 1

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

Propagation

This Worm drops copies of itself in all removable drives.

Other Details

This Worm connects to the following possibly malicious URL:

  • {BLOCKED}uhufdr.cc
  • {BLOCKED}hrguhr.cc
  • {BLOCKED}uuruur.cc
  • {BLOCKED}guguur.cc
  • {BLOCKED}eghuur.cc
  • {BLOCKED}fiheir.cc
  • {BLOCKED}ieirdr.cc
  • {BLOCKED}gihisr.cc
  • {BLOCKED}uhfuhr.cc
  • {BLOCKED}ezfzgr.cc
  • {BLOCKED}efuhgr.cc
  • {BLOCKED}huefur.cc
  • {BLOCKED}eitter.cc
  • {BLOCKED}aeofkr.cc
  • {BLOCKED}zueutr.cc
  • {BLOCKED}hrguho.co
  • {BLOCKED}uhufdo.co
  • {BLOCKED}uuruuo.co
  • {BLOCKED}guguuo.co
  • {BLOCKED}eghuuo.co
  • {BLOCKED}fiheio.co
  • {BLOCKED}ieirdo.co
  • {BLOCKED}gihiso.co
  • {BLOCKED}uhfuho.co
  • {BLOCKED}ezfzgo.co
  • {BLOCKED}efuhgo.co
  • {BLOCKED}huefuo.co
  • {BLOCKED}eitteo.co
  • {BLOCKED}aeofko.co
  • {BLOCKED}zueuto.co
  • {BLOCKED}hrguhp.io
  • {BLOCKED}uhufdp.io
  • {BLOCKED}uuruup.io
  • {BLOCKED}guguup.io
  • {BLOCKED}eghuup.io
  • {BLOCKED}fiheip.io
  • {BLOCKED}ieirdp.io
  • {BLOCKED}gihisp.io
  • {BLOCKED}uhfuhp.io
  • {BLOCKED}ezfzgp.io
  • {BLOCKED}efuhgp.io
  • {BLOCKED}huefup.io
  • {BLOCKED}eittep.io
  • {BLOCKED}aeofkp.io
  • {BLOCKED}zueutp.io
  • {BLOCKED}hrguhl.su
  • {BLOCKED}uhufdl.su
  • {BLOCKED}uuruul.su
  • {BLOCKED}guguul.su
  • {BLOCKED}eghuul.su
  • {BLOCKED}fiheil.su
  • {BLOCKED}ieirdl.su
  • {BLOCKED}gihisl.su
  • {BLOCKED}uhfuhl.su
  • {BLOCKED}ezfzgl.su
  • {BLOCKED}efuhgl.su
  • {BLOCKED}hueful.su
  • {BLOCKED}eittel.su
  • {BLOCKED}aeofkl.su
  • {BLOCKED}zueutl.su

It does the following:

  • It moves all files and folders in the removable or network drive inside the created {removable}:\__ folder

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

15.258.04

FIRST VSAPI PATTERN DATE:

26 Jul 2019

VSAPI OPR PATTERN File:

15.259.00

VSAPI OPR PATTERN Date:

27 Jul 2019

Step 1

Before doing any scans, Windows 7, Windows 8, Windows 8.1, and Windows 10 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.Win32.DORKBOT.TIGAAAR

[ 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

Restore these modified registry values

[ Learn More ]

Important:Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this only if you know how to or you can seek your system administrator's help. You may also check out this Microsoft article first before modifying your computer's registry.

  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center
    • From: AntiVirusOverride = 1
      To: AntiVirusOverride = 0
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center
    • From: UpdatesOverride = 1
      To: UpdatesOverride = 0
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center
    • From: FirewallOverride = 1
      To: FirewallOverride = 0
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center
    • From: AntiVirusDisableNotify = 1
      To: AntiVirusDisableNotify = 0
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center
    • From: UpdatesDisableNotify = 1
      To: UpdatesDisableNotify = 0
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center
    • From: AutoUpdateDisableNotify = 1
      To: AutoUpdateDisableNotify = 0
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center
    • From: FirewallDisableNotify = 1
      To: FirewallDisableNotify = 0

Step 5

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\Run
    • Microsoft Windows Driver = %Windows%\2032827881\sysrxs.exe
  • In HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    • Microsoft Windows Driver = %Windows%\2032827881\sysrxs.exe

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.
  • %Application Data%\winsvcs.txt
  • {Removable Drive}:\.lnk

Step 7

Scan your computer with your Trend Micro product to delete files detected as Worm.Win32.DORKBOT.TIGAAAR. 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 the following Trend Micro Support pages for more information:


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