WORM_NITOL.JG

 Analysis by: Francis Xavier Antazo
 Modified by: John Kevin Sanchez

 ALIASES:

DDoS:Win32/Nitol.A (Microsoft), Virus.Win32.Dzan.a (KASPERSKY), Win32/ServStart.AC trojan (NOD32)

 PLATFORM:

Windows

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

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted:

  • 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.

  TECHNICAL DETAILS

File Size:

44,032 bytes

File Type:

DLL

Memory Resident:

Yes

Initial Samples Received Date:

01 Feb 2013

Arrival Details

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.

Installation

This worm drops the following component file(s):

  • %System%\{random}.exe

(Note: %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.)

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

  • %System%\hra33.dll

(Note: %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.)

Autostart Technique

This worm registers its dropped component as a system service to ensure its automatic execution at every system startup. It does this by creating the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Nationalgnf
ImagePath = "%System%\{random file name}.exe"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Nationalgnf
Description = "Providesgkl a domain server for NI security"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Nationalgnf
DisplayName = "Nationaltdb Instruments Domain Service"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Nationalgnf
ErrorControl = "0"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Nationalgnf
ObjectName = "LocalSystem"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Nationalgnf
Start = "2"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Nationalgnf
Type = "10"

Other System Modifications

This worm adds the following registry keys:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Nationalgnf\Enum

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Nationalgnf\Security

Other Details

This worm connects to the following possibly malicious URL:

  • http://dd.{BLOCKED}nren.com

NOTES:

This worm drops the following copy of itself in all folders in all physical and removable drives containing an EXE file:

  • lpk.dll

It drops the following copy of the dropped component file every time it is run:

  • %User Temp%\hrl{2 random characters}.tmp

  SOLUTION

Minimum Scan Engine:

9.700

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

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\SYSTEM\CurrentControlSet\Services\Nationalgnf
    • ImagePath = "%System%\{random file name}.exe"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Nationalgnf
    • Description = "Providesgkl a domain server for NI security"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Nationalgnf
    • DisplayName = "Nationaltdb Instruments Domain Service"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Nationalgnf
    • ErrorControl = "0"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Nationalgnf
    • ObjectName = "LocalSystem"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Nationalgnf
    • Start = "2"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Nationalgnf
    • Type = "10"

Step 4

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.

  • HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Nationalgnf\Enum
  • HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Nationalgnf\Security

Step 5

Search and delete these files

[ 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.
  • %System%\{random}.exe
  • %User Temp%\hrl{2 random characters}.tmp

Step 6

Scan your computer with your Trend Micro product to clean files detected as WORM_NITOL.JG. 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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