TROJ_NJWORM.DK
Windows
Threat Type: Trojan
Destructiveness: No
Encrypted:
In the wild: Yes
OVERVIEW
This Trojan 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
338,961 bytes
EXE
Yes
09 Jan 2015
Arrival Details
This Trojan 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 Trojan drops the following copies of itself into the affected system and executes them:
- %User Temp%\WinAutoi.exe
(Note: %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)
It drops the following files:
- %User Temp%\WinAutoi.exe.ini
(Note: %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)
Autostart Technique
This Trojan adds the following registry entries to enable its automatic execution at every system startup:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
WinAutoi.exe = "%User Temp%\WinAutoi.exe"
HKEY_CURRENT_USER\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
WinAutoi.exe = "%User Temp%\WinAutoi.exe"
It drops the following file(s) in the Windows User Startup folder to enable its automatic execution at every system startup:
- %User Startup%\WinAutoi.exe
(Note: %User Startup% is the current user's Startup folder, which is usually C:\Windows\Profiles\{user name}\Start Menu\Programs\Startup on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Start Menu\Programs\Startup on Windows NT, and C:\Documents and Settings\{User name}\Start Menu\Programs\Startup.)
Other System Modifications
This Trojan modifies the following file(s):
- %System Root%\IO.SYS
- %System Root%\MSDOS.SYS
- %System Root%\NTDETECT.COM
- %System Root%\ntldr
(Note: %System Root% is the Windows root folder, where it usually is C:\ on all Windows operating system versions.)
It deletes the following files:
- %System Root%\Email and Password List.vbs
(Note: %System Root% is the Windows root folder, where it usually is C:\ on all Windows operating system versions.)
It creates the following registry entry(ies) to bypass Windows Firewall:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\AuthorizedApplications\
List
%User Temp%\WinAutoi.exe = "%User Temp%\WinAutoi.exe:*:Enabled:WinAutoi.exe"
Other Details
This Trojan connects to the following possibly malicious URL:
- a.servecounterstrike.com
NOTES:
The aforementioned modified files only applies to Windows XP. This malware removes the hidden attribute of the said files.
SOLUTION
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
Identify and terminate files detected as TROJ_NJWORM.DK
- 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.
- 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.
- 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
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
- WinAutoi.exe = "%User Temp%\WinAutoi.exe"
- WinAutoi.exe = "%User Temp%\WinAutoi.exe"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
- WinAutoi.exe = "%User Temp%\WinAutoi.exe"
- WinAutoi.exe = "%User Temp%\WinAutoi.exe"
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\AuthorizedApplications\List
- %User Temp%\WinAutoi.exe = "%User Temp%\WinAutoi.exe:*:Enabled:WinAutoi.exe"
- %User Temp%\WinAutoi.exe = "%User Temp%\WinAutoi.exe:*:Enabled:WinAutoi.exe"
Step 5
Search and delete this file
- %User Temp%\WinAutoi.exe
- %User Startup%\WinAutoi.exe
- %User Temp%\WinAutoi.exe.ini
Step 6
- Open a command prompt.
- For Windows 2000, Windows XP, and Windows Server 2003 users, click Start>Run. In the Search box, type CMD then press Enter.
- For Windows Vista, Windows 7, and Windows Server 2008 users, click Start, type CMD in the Search input field then press Enter.
- For Windows 8, Windows 8.1, and Windows Server 2012 users, right-click on the lower-left corner of the screen, click Command Prompt.
- In the CMD console, type the following:
ATTRIB [+R | -R] [+A | -A ] [+S | -S] [+H | -H] [+I | -I] [drive:][path][file name] [/S [/D] [/L]]
Where:
+ Sets an attribute.
- Clears an attribute
R Read-only file attribute
A Archive file attribute
S System file attribute
H Hidden file attribute
I Not content indexed file attribute
[drive:][path][filename]
Specifies a file or files for attrib to process
/S Processes matching files in the current folder and all subfolders.
/D Processes folders
/L Work on the attributes of the Symbolic Link versus the target of the Symbolic Link
Example:
To unhide all files and folders (including subfolders) in drive D:
ATTRIB –H D:\* /S /D
- Repeat Step 3 for folders and files in other drives or folders.
Step 7
Scan your computer with your Trend Micro product to delete files detected as TROJ_NJWORM.DK. 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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