Worm.Win32.DOWNAD.NLJ
Net-Worm.Win32.Kido.ih (KASPERSKY)
Windows

Threat Type: Worm
Destructiveness: No
Encrypted:
In the wild: Yes
OVERVIEW
Downloaded from the Internet, Dropped by other malware
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 does not have any backdoor routine.
TECHNICAL DETAILS
162,941 bytes
EXE
Yes
24 Aug 2017
Drops files, Modifies system registry, Creates files
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:
- %System%\viajus.dll
(Note: %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.)
It adds the following processes:
- netsh interface tcp set global autotuning=disabled
Autostart Technique
This Worm registers itself as a system service to ensure its automatic execution at every system startup by adding the following registry entries:
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
services\{Random Characters}
DisplayName = {Random Characters}
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
services\{Random Characters}
Type = 32
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
services\{Random Characters}
Start = 2
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
services\{Random Characters}
ErrorControl = 0
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
services\{Random Characters}
ImagePath = %System%\svchost.exe -k netsvcs
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
services\{Random Characters}
ObjectName = LocalSystem
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
services\{Random Characters}\Parameters
ServiceDll = %System%\viajus.dll
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Svchost
netsvcs = {Default Services}, {Service Created By the Malware}
(Note: The default value data of the said registry entry is {Default Services}.)
Propagation
This Worm creates the following folders in all removable drives:
- {Drive Letter}:\RECYCLER\{SID}
It drops the following copy(ies) of itself in all removable drives:
- {Drive Letter}:\RECYCLER\{SID}\jwgkvsq.vmx
It modifies the contents of an existing AUTORUN.INF file to automatically execute its dropped copy. It does this by adding the following strings in the .INF file:
- {Drive Letter}:\autorun.inf
- {Garbage Characters}
- [AUTorun
- {Garbage Characters}
- AcTION = Open folder to view files
- {Garbage Characters}
- icon = %syStEmrOot%\sySTEM32\sHELL32.Dll,4
- {Garbage Characters}
- shelLExECUte = RuNdLl32.EXE .\RECYCLER\{SID}\jwgkvsq.vmx,ahaezedrn
- {Garbage Characters}
- useAuTopLAY=1
Backdoor Routine
This Worm does not have any backdoor routine.
Rootkit Capabilities
This Worm does not have rootkit capabilities.
Other Details
This Worm connects to the following possibly malicious URL:
- http://www.whatsmyipaddress.com
- http://checkip.dydns.org
- http://www.whatismyip.org
- http://www.yahoo.com
- http://www.ask.com
- http://www.baidu.com
It does the following:
- It modifies the attributes of the created folders into the following:
- System
- Hidden
- Read-only
- It modifies the attributes of the dropped files into the following:
- Archive
- System
- Hidden
- Read-only
SOLUTION
9.800
18.666.04
30 Aug 2023
18.667.00
31 Aug 2023
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
Restart in Safe Mode
Step 4
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_LOCAL_MACHINE\SYSTEM\ControlSet001\services\{Random Characters}
- DisplayName = {Random Characters}
- DisplayName = {Random Characters}
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\services\{Random Characters}
- Type = 32
- Type = 32
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\services\{Random Characters}
- Start = 2
- Start = 2
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\services\{Random Characters}
- ErrorControl = 0
- ErrorControl = 0
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\services\{Random Characters}
- ImagePath = %System%\svchost.exe -k netsvcs
- ImagePath = %System%\svchost.exe -k netsvcs
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\services\{Random Characters}
- ObjectName = LocalSystem
- ObjectName = LocalSystem
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\services\{Random Characters}\Parameters
- ServiceDll = %System%\viajus.dll
- ServiceDll = %System%\viajus.dll
Step 5
Restore this modified 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_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Svchost
- netsvcs = {Default Services}, {Service Created By the Malware}
- netsvcs = {Default Services}, {Service Created By the Malware}
Step 6
Delete this registry key
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\SYSTEM\ControlSet001\services\{Random Characters}\
- Parameters
- Parameters
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\services\
- {Random Characters}
- {Random Characters}
Step 7
Search and delete AUTORUN.INF files created by Worm.Win32.DOWNAD.NLJ that contain these strings
- {Garbage Characters}
- [AUTorun
- AcTION = Open folder to view files
- icon = %syStEmrOot%\sySTEM32\sHELL32.Dll,4
- shelLExECUte = RuNdLl32.EXE .\RECYCLER\{SID}\jwgkvsq.vmx,ahaezedrn
- useAuTopLAY=1
Step 8
Search and delete these files
- In %System%\
- viajus.dll
- viajus.dll
- In {Drive Letter}:\RECYCLER\{SID}\
- jwgkvsq.vmx
- jwgkvsq.vmx
Step 9
Search and delete these folders
- In {Drive Letter}:\RECYCLER\
- {SID}
- {SID}
- In {Drive Letter}:\
- RECYCLER
- RECYCLER
Step 10
Restart in normal mode and scan your computer with your Trend Micro product for files detected as Worm.Win32.DOWNAD.NLJ. 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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