TROJ_NSANTI.R
TrojanDownloader:Win32/Zlob.BBD (Microsoft); Generic.dx (McAfee); W32.Fubalca.N (Symantec); Packed.Win32.NSAnti.r (Kaspersky); Worm.Win32.Taterf.b (v) (Sunbelt); Packer.Malware.NSAnti.1 (FSecure)
Windows 2000, Windows XP, Windows Server 2003
![](/vinfo/imgFiles/legend.jpg)
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.
It modifies files, disabling programs and applications from properly running.
TECHNICAL DETAILS
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.
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
svc = "{malware path and file name}"
Other System Modifications
This Trojan modifies the following files:
- %Program Files%\common files\microsoft shared\stationery\Blank.htm
- %Program Files%\common files\microsoft shared\stationery\Citrus Punch.htm
- %Program Files%\common files\microsoft shared\stationery\Clear Day.htm
- %Program Files%\common files\microsoft shared\stationery\Fiesta.htm
- %Program Files%\common files\microsoft shared\stationery\Glacier.htm
- %Program Files%\common files\microsoft shared\stationery\Ivy.htm
- %Program Files%\common files\microsoft shared\stationery\Leaves.htm
- %Program Files%\common files\microsoft shared\stationery\Maize.htm
- %Program Files%\common files\microsoft shared\stationery\Nature.htm
- %Program Files%\common files\microsoft shared\stationery\Network Blitz.htm
- %Program Files%\common files\microsoft shared\stationery\Pie Charts.htm
- %Program Files%\common files\microsoft shared\stationery\Sunflower.htm
- %Program Files%\common files\microsoft shared\stationery\Sweets.htm
- %Program Files%\common files\microsoft shared\stationery\Technical.htm
- %Program Files%\common files\system\ado\MDACReadme.htm
- %Program Files%\netmeeting\netmeet.htm
(Note: %Program Files% is the default Program Files folder, usually C:\Program Files in Windows 2000, Server 2003, and XP (32-bit), Vista (32-bit), and 7 (32-bit), or C:\Program Files (x86) in Windows XP (64-bit), Vista (64-bit), and 7 (64-bit).)
It deletes the following files:
- %Temp%\scs1.tmp
- %Temp%\scs2.tmp
(Note: %Temp% is the Windows Temporary folder, which is usually C:\Windows\Temp.)
It adds the following registry entries:
HKEY_CLASSES_ROOT
.grp = "MSProgramGroup"
HKEY_CLASSES_ROOT
MSProgramGroup = "Microsoft Program Group"
HKEY_CLASSES_ROOT
MSProgramGroup\Shell\Open\Command = "%System%\grpconv.exe %1"
It modifies the following registry entries:
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\GrpConv
Log = "Init Application."
(Note: The default value data of the said registry entry is Uninit Application..)
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\GrpConv
Log = "bdg: ..."
(Note: The default value data of the said registry entry is Uninit Application..)
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\GrpConv
Log = "bdg: Done."
(Note: The default value data of the said registry entry is Uninit Application..)
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\GrpConv
Log = "dros: ..."
(Note: The default value data of the said registry entry is Uninit Application..)
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\GrpConv
Log = "dros: Renames."
(Note: The default value data of the said registry entry is Uninit Application..)
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\GrpConv
Log = "dros: Copies."
(Note: The default value data of the said registry entry is Uninit Application..)
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\GrpConv
Log = "dros: Deletes."
(Note: The default value data of the said registry entry is Uninit Application..)
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\GrpConv
Log = "dros: Done."
(Note: The default value data of the said registry entry is Uninit Application..)
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\GrpConv
Log = "Uninit Application."
(Note: The default value data of the said registry entry is Uninit Application..)
Dropping Routine
This Trojan drops the following files:
- %System Root%\npf.sys
- %System Root%\_wpcap_.bat
- %System Root%\_wpcap_.inf
- %Temporary Internet Files%\content.ie5\zsgkjko6\help[1].htm
- %Program Files%\adobe\reader 10.0\reader\legal\enu\license.html
- %Program Files%\adobe\reader 10.0\ReadMe.htm
- %User Temp%\help.exe
(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.. %Temporary Internet Files% is the Temporary Internet Files folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temporary Internet Files on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Local\Microsoft\Windows\Temporary Internet Files on Windows Vista and 7.. %Program Files% is the default Program Files folder, usually C:\Program Files in Windows 2000, Server 2003, and XP (32-bit), Vista (32-bit), and 7 (32-bit), or C:\Program Files (x86) in Windows XP (64-bit), Vista (64-bit), and 7 (64-bit).. %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 Details
This Trojan connects to the following possibly malicious URL:
- http://www.{BLOCKED}0.com/mfx/help.exe
This report is generated via an automated analysis system.
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
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\Software\Microsoft\Windows\CurrentVersion\Run
- svc = "{malware path and file name}"
- In HKEY_CLASSES_ROOT
- .grp = "MSProgramGroup"
- In HKEY_CLASSES_ROOT
- MSProgramGroup = "Microsoft Program Group"
- In HKEY_CLASSES_ROOT
- MSProgramGroup\Shell\Open\Command = "%System%\grpconv.exe %1"
Step 4
Restore these modified registry values
Important:Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this only if you know how to or you can seek your system administrator's help. You may also check out this Microsoft article first before modifying your computer's registry.
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\GrpConv
- From: Log = "Init Application."
To: Log = ""Uninit Application.""
- From: Log = "Init Application."
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\GrpConv
- From: Log = "bdg: ..."
To: Log = ""Uninit Application.""
- From: Log = "bdg: ..."
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\GrpConv
- From: Log = "bdg: Done."
To: Log = ""Uninit Application.""
- From: Log = "bdg: Done."
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\GrpConv
- From: Log = "dros: ..."
To: Log = ""Uninit Application.""
- From: Log = "dros: ..."
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\GrpConv
- From: Log = "dros: Renames."
To: Log = ""Uninit Application.""
- From: Log = "dros: Renames."
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\GrpConv
- From: Log = "dros: Copies."
To: Log = ""Uninit Application.""
- From: Log = "dros: Copies."
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\GrpConv
- From: Log = "dros: Deletes."
To: Log = ""Uninit Application.""
- From: Log = "dros: Deletes."
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\GrpConv
- From: Log = "dros: Done."
To: Log = ""Uninit Application.""
- From: Log = "dros: Done."
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\GrpConv
- From: Log = "Uninit Application."
To: Log = ""Uninit Application.""
- From: Log = "Uninit Application."
Step 5
Search and delete these components
- %System Root%\npf.sys
- %System Root%\_wpcap_.bat
- %System Root%\_wpcap_.inf
- %Temporary Internet Files%\content.ie5\zsgkjko6\help[1].htm
- %Program Files%\adobe\reader 10.0\reader\legal\enu\license.html
- %Program Files%\adobe\reader 10.0\ReadMe.htm
- %User Temp%\help.exe
Step 6
Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_NSANTI.R. 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.
Step 7
Restore deleted/modified files and/or registry entries from backup
*Note: Only Microsoft-related files/keys/values will be restored. If this malware/grayware also deleted registry keys/values related to programs that are not from Microsoft, please reinstall those programs on your computer.
- %Program Files%\common files\microsoft shared\stationery\Blank.htm
- %Program Files%\common files\microsoft shared\stationery\Citrus Punch.htm
- %Program Files%\common files\microsoft shared\stationery\Clear Day.htm
- %Program Files%\common files\microsoft shared\stationery\Fiesta.htm
- %Program Files%\common files\microsoft shared\stationery\Glacier.htm
- %Program Files%\common files\microsoft shared\stationery\Ivy.htm
- %Program Files%\common files\microsoft shared\stationery\Leaves.htm
- %Program Files%\common files\microsoft shared\stationery\Maize.htm
- %Program Files%\common files\microsoft shared\stationery\Nature.htm
- %Program Files%\common files\microsoft shared\stationery\Network Blitz.htm
- %Program Files%\common files\microsoft shared\stationery\Pie Charts.htm
- %Program Files%\common files\microsoft shared\stationery\Sunflower.htm
- %Program Files%\common files\microsoft shared\stationery\Sweets.htm
- %Program Files%\common files\microsoft shared\stationery\Technical.htm
- %Program Files%\common files\system\ado\MDACReadme.htm
- %Program Files%\netmeeting\netmeet.htm
Step 8
Restore this file from backup only Microsoft-related files will be restored. If this malware/grayware also deleted files related to programs that are not from Microsoft, please reinstall those programs on you computer again.
- %Temp%\scs1.tmp
- %Temp%\scs2.tmp
Did this description help? Tell us how we did.