Worm.Win32.SOHANAD.CY
Windows
Threat Type: Worm
Destructiveness: No
Encrypted: No
In the wild: Yes
OVERVIEW
This Worm arrives via removable drives. It arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.
It disables Task Manager, Registry Editor, and Folder Options.
TECHNICAL DETAILS
Arrival Details
This Worm arrives via removable drives.
It may arrive via network shares.
It 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:
- %System%\system3_.exe
- %Windows%\system3_.exe
- {Drive name}\system3_.exe
- {Drive name}\New Folder.exe
- {Removable drive name}\system3_.exe
- {Removable drive name}\New Folder.exe
- {Shared network name}\system3_.exe
- {Shared network name}\New Folder.exe
(Note: %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.. %Windows% is the Windows folder, where it usually is C:\Windows on all Windows operating system versions.)
It adds the following processes:
- %System%\cmd.exe /C AT /delete /yes
- %System%\cmd.exe /C AT 09:00 /interactive /EVERY:m,t,w,th,f,s,su %System%\system3_.exe
(Note: %System% is the Windows system folder, where it usually is C:\Windows\System32 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_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
Yahoo Messengger = "%System%\system3_.exe"
HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\
Microsoft\Windows NT\CurrentVersion\
Winlogon
Shell = "Explorer.exe system3_.exe"
Other System Modifications
This Worm deletes the following folders:
- %System Root%\System Volume Information
(Note: %System Root% is the Windows root folder, where it usually is C:\ on all Windows operating system versions.)
It adds the following registry entries:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
services\Schedule
AtTaskMaxHours = "0"
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
WorkgroupCrawler\Shares
shared = "\New Folder.exe"
It creates the following registry entry(ies) to disable Task Manager, Registry Tools and Folder Options:
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
Explorer
NofolderOptions = "1"
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
System
DisableTaskMgr = "1"
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
System
DisableRegistryTools = "1"
Process Termination
This Worm terminates the following processes if found running in the affected system's memory:
- game_y.exe
- cmd.exe
Dropping Routine
This Worm drops the following files:
- {Removable Drive name}\autorun.inf
- {Shared Network name}\autorun.inf
- {Drive name}\autorun.inf -> autorun for system3_.exe
- %System%\autorun.ini -> autorun for system3_.exe
(Note: %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.)
Download Routine
This Worm accesses the following websites to download files:
- http://h1.{BLOCKED}y.com/asdb0xx/setting.ini - where xx is from 00 to 50, counting by twos (02, 04, 06, etc.)
- http://www.balu0xx.{BLOCKED}h.com/set/setting.ini - where xx is from 00 to 20
It downloads an updated copy of itself from the following website(s):
- http://h1.{BLOCKED}y.com/adb00xx - where xx is from 01 to 50
It saves the files it downloads using the following names:
- %System%\_setting.ini
(Note: %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.)
Other Details
This Worm does the following:
- It copies itself to every .exe file in all folders of the Removable Drive and Shared Network
- It terminates the following Windows if found running on the affected system:
- System Configuration
- Registry
- Windows Task
- Bkav2006
- [FireLion]
- It deletes the autorun registry of the following Windows if found running on the affected system:
- Bkav2006
- [FireLion]
- It changes the browser homepage to the following:
- http://www.mydreamworld.{BLOCKED}s.com
- http://www.advgoogle.{BLOCKED}ot.com
- It sends spam messages using the following messaging apps:
- Yahoo Messenger
- Google Talk
- It would not continue to its malicious routine if the file "c:\install.txt" exists in the victim's machine
- It would not terminate any process or window if the file "c:\god.txt" exists in the victim's machine
- It would not drop any file to the drives, removable drives or shared network if the file "c:\disk.txt" is found in the victim's machine
It does not proceed to its malicious routine if it detects that it is being debugged.
SOLUTION
Step 1
Trend Micro Predictive Machine Learning detects and blocks malware at the first sign of its existence, before it executes on your system. When enabled, your Trend Micro product detects this malware under the following machine learning name:
- TROJ.Win32.TRX.XXPE50FLM011
Step 2
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 3
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 4
Restart in Safe Mode
Step 5
Enable Registry Editor, Task Manager, and Folder options
Step 6
Delete this registry value
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
- Yahoo Messengger = "%System%\system3_.exe"
- Yahoo Messengger = "%System%\system3_.exe"
Step 7
Restore these modified registry values
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\SYSTEM\CurrentControlSet\services\Schedule
- AtTaskMaxHours = "0"
- AtTaskMaxHours = "0"
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\WorkgroupCrawler\Shares
- shared = "\New Folder.exe"
- shared = "\New Folder.exe"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\Windows NT\CurrentVersion\Winlogon
- Shell = "Explorer.exe system3_.exe"
- Shell = "Explorer.exe system3_.exe"
Step 8
Search and delete these files
- %System%\system3_.exe
- %Windows%\system3_.exe
- {Drive name}\system3_.exe
- {Drive name}\New Folder.exe
- {Removable drive name}\system3_.exe
- {Removable drive name}\New Folder.exe
- {Shared network name}\system3_.exe
- {Shared network name}\New Folder.exe
- {Removable Drive name}\autorun.inf
- {Shared Network name}\autorun.inf
- {Drive name}\autorun.inf
- %System%\autorun.ini
- %System%\_setting.ini
Step 9
Restart in normal mode and scan your computer with your Trend Micro product for files detected as Worm.Win32.SOHANAD.CY. 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.
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