VBS_DLOADR.NC
VBS/DwnLdr-KXE (Sophos), Worm:VBS/Linxer.A (Microsoft), VBS/TrojanDownloader.Agent.NHP trojan (NOD32)
Windows 2000, Windows Server 2003, Windows XP (32-bit, 64-bit), Windows Vista (32-bit, 64-bit), Windows 7 (32-bit, 64-bit)
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.
However, as of this writing, the said sites are inaccessible.
TECHNICAL DETAILS
6,799 bytes
VBS
Yes
23 Apr 2013
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 file(s)/component(s):
- %User Startup%\FlashPlayerPlug.lnk
(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.)
It drops the following copies of itself into the affected system:
- %User Temp%\Facebook.vbs
(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista and 7.)
Autostart Technique
This Trojan adds the following registry entries to enable its automatic execution at every system startup:
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
Facebook.vbs = ""%User Temp%\Facebook.vbs""
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
Facebook.vbs = ""%User Temp%\Facebook.vbs""
It enables its automatic execution at every system startup by dropping the following copies of itself into the Windows Common Startup folder:
- %User Startup%\Facebook.vbs
(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 adds the following registry entries as part of its installation routine:
HKEY_CURRENT_USER
njq8 = "n"
Download Routine
This Trojan accesses the following websites to download files:
- http://{BLOCKED}l.dropbox.com/s/fqlbp4q0pz67dy9/FlashPlayerUpdt.exe?dl=1
It saves the files it downloads using the following names:
- %Application Data%\FlashPlayerMsj.exe
(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, XP, and Server 2003, or C:\Users\{user name}\AppData\Roaming on Windows Vista and 7.)
Other Details
However, as of this writing, the said sites are inaccessible.
SOLUTION
9.300
9.988.07
23 Apr 2013
9.989.00
24 Apr 2013
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
Restart in Safe Mode
Step 3
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
- njq8 = "n"
- njq8 = "n"
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
- Facebook.vbs = ""%User Temp%\Facebook.vbs""
- Facebook.vbs = ""%User Temp%\Facebook.vbs""
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
- Facebook.vbs = ""%User Temp%\Facebook.vbs""
- Facebook.vbs = ""%User Temp%\Facebook.vbs""
Step 4
Search and delete these files
- %Application Data%\FlashPlayerMsj.exe
- %User Temp%\Facebook.vbs
- %User Startup%\Facebook.vbs
- %User Startup%\FlashPlayerPlug.lnk
Step 5
Restart in normal mode and scan your computer with your Trend Micro product for files detected as VBS_DLOADR.NC. 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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