ADW_SOMOTO
a variant of Win32/Somoto.A application(Eset)
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: Adware
Destructiveness: No
Encrypted:
In the wild: Yes
OVERVIEW
This adware may be manually installed by a user.
TECHNICAL DETAILS
Arrival Details
This adware may be manually installed by a user.
Installation
This adware adds the following folders:
- %All Users Profile%\SafetyNut (Windows Vista and higher versions)
- %All Users Profile%\Application Data\SafetyNut (Versions lower than Windows Vista)
(Note: %All Users Profile% is the All Users or Common profile folder, which is C:\Documents and Settings\All Users in Windows 2000, XP, and Server 2003, and C:\ProgramData in Windows Vista and 7.)
It drops the following files:
- %User Temp%\nsi16.tmp\bi_client.exe
- %User Temp%\nsn13.tmp\bi_client.exe
- %User Temp%\nst10.tmp\bi_client.exe
- %User Temp%\nstD.tmp\bi_client.exe
- %User Temp%\nsv19.tmp\bi_client.exe
- %User Temp%\biclient.exe
(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.)
Other System Modifications
This adware adds the following registry keys:
HKEY_LOCAL_MACHINE\SOFTWARE\SafetyNut
HKEY_LOCAL_MACHINE\SOFTWARE\SafetyNut\
General
It adds the following registry entries:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Control\Session Manager
PendingFileRenameOperations = "%User Temp%\nstD.tmp\bi_client.exe"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Control\Session Manager
PendingFileRenameOperations = "%User Temp%\biclient.exe"
It modifies the following registry entries:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
DirectDraw\MostRecentApplication
Name = "biclient.exe"
(Note: The default value data of the said registry entry is aim.exe.)
NOTES:
ADW_SOMOTO is used to download applications from the following URLs:
- http://{BLOCKED}i.{BLOCKED}v.com/awjpfreezip73272/freezipuyiv
- http://{BLOCKED}ln.{BLOCKED}ldog.com/css/Tokyo/TokyoDefault.css
- http://{BLOCKED}ln.{BLOCKED}ldog.com/images/Tokyo/tokyoLightGrayStripesBG.jpg
- http://{BLOCKED}c.{BLOCKED}v.com/js/libs/storage.swf?767416
- http://{BLOCKED}i.{BLOCKED}v.com/pinger
SOLUTION
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
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\CurrentControlSet\Control\Session Manager
- PendingFileRenameOperations = "%User Temp%\nstD.tmp\bi_client.exe"
- PendingFileRenameOperations = "%User Temp%\nstD.tmp\bi_client.exe"
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager
- PendingFileRenameOperations = "%User Temp%\biclient.exe"
- PendingFileRenameOperations = "%User Temp%\biclient.exe"
Step 3
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\DirectDraw\MostRecentApplication
- From: Name = "biclient.exe"
To: Name = aim.exe
- From: Name = "biclient.exe"
Step 4
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\SOFTWARE
- SafetyNut
- SafetyNut
Step 5
Search and delete this folder
- %All Users Profile%\SafetyNut (Windows Vista and higher versions)
- %All Users Profile%\Application Data\SafetyNut (Versions lower than Windows Vista)
Step 6
Search and delete these files
- %User Temp%\nsi16.tmp\bi_client.exe
- %User Temp%\nsn13.tmp\bi_client.exe
- %User Temp%\nst10.tmp\bi_client.exe
- %User Temp%\nstD.tmp\bi_client.exe
- %User Temp%\nsv19.tmp\bi_client.exe
- %User Temp%\biclient.exe
Step 7
Scan your computer with your Trend Micro product to delete files detected as ADW_SOMOTO. 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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