TROJ_BHO.SK
Trojan:Win32/Zlob.gen!Q (Microsoft); Generic PUP.x. (McAfee); Trojan.Zlob (Symantec); ARC:NSIS, [wnlmdakqkpm.dll]:Trojan.Win32.Vapsup.aazt, [bgrqfetx.dll]:Trojan.Win32.Genome.kudv, [xokv (Kaspersky); NetAdware (Sunbelt); Trojan.Zlob.34764 (FSecure)
Windows 2000, Windows XP, Windows Server 2003

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
342,366 bytes
EXE
No
07 Nov 2012
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 creates the following folders:
- %System Root%\DOCUME~1
- %System Root%\DOCUME~1\ADMINI~1
- %User Profile%\LOCALS~1
- %User Temp%\nsf3.tmp
- %User Temp%\ac8zt2
(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.. %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003, or C:\Users\{user name} on Windows Vista and 7.. %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 registers itself as a BHO to ensure its automatic execution every time Internet Explorer is used by adding the following registry keys:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Explorer\
Browser Helper Objects\{AA890517-C937-403F-800F-C319A8406565}
Other System Modifications
This Trojan deletes the following files:
- %User Temp%\nsf1.tmp
- %User Temp%\nsf3.tmp
(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.)
It adds the following registry keys:
HKEY_CLASSES_ROOT\bgrqfetx.ToolBar.1
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
bgrqfetx.ToolBar.1\CLSID
HKEY_CLASSES_ROOT\bgrqfetx.bdbn
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
bgrqfetx.bdbn\CLSID
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
bgrqfetx.bdbn\CurVer
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{72B68A1C-58DD-41B5-B619-D78A182A77D9}
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{72B68A1C-58DD-41B5-B619-D78A182A77D9}\ProgID
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{72B68A1C-58DD-41B5-B619-D78A182A77D9}\VersionIndependentProgID
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{72B68A1C-58DD-41B5-B619-D78A182A77D9}\Programmable
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{72B68A1C-58DD-41B5-B619-D78A182A77D9}\InprocServer32
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{72B68A1C-58DD-41B5-B619-D78A182A77D9}\TypeLib
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
TypeLib\{25DC337D-A3EA-4D03-AC84-F89F5B0C461D}
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
TypeLib\{25DC337D-A3EA-4D03-AC84-F89F5B0C461D}\1.0
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
TypeLib\{25DC337D-A3EA-4D03-AC84-F89F5B0C461D}\1.0\
FLAGS
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
TypeLib\{25DC337D-A3EA-4D03-AC84-F89F5B0C461D}\1.0\
0
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
TypeLib\{25DC337D-A3EA-4D03-AC84-F89F5B0C461D}\1.0\
0\win32
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
TypeLib\{25DC337D-A3EA-4D03-AC84-F89F5B0C461D}\1.0\
HELPDIR
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Interface\{61E35336-39DD-46AD-B7DA-172A4E6CAC3B}
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Interface\{61E35336-39DD-46AD-B7DA-172A4E6CAC3B}\ProxyStubClsid
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Interface\{61E35336-39DD-46AD-B7DA-172A4E6CAC3B}\ProxyStubClsid32
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Interface\{61E35336-39DD-46AD-B7DA-172A4E6CAC3B}\TypeLib
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Explorer\
Browser Helper Objects
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{AA890517-C937-403F-800F-C319A8406565}
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{AA890517-C937-403F-800F-C319A8406565}\ProgID
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{AA890517-C937-403F-800F-C319A8406565}\VersionIndependentProgID
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{AA890517-C937-403F-800F-C319A8406565}\Programmable
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{AA890517-C937-403F-800F-C319A8406565}\InprocServer32
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{AA890517-C937-403F-800F-C319A8406565}\TypeLib
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
TypeLib\{0291E0A0-EB01-49C1-9B69-8BF670841C5E}
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
TypeLib\{0291E0A0-EB01-49C1-9B69-8BF670841C5E}\1.0
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
TypeLib\{0291E0A0-EB01-49C1-9B69-8BF670841C5E}\1.0\
FLAGS
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
TypeLib\{0291E0A0-EB01-49C1-9B69-8BF670841C5E}\1.0\
0
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
TypeLib\{0291E0A0-EB01-49C1-9B69-8BF670841C5E}\1.0\
0\win32
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
TypeLib\{0291E0A0-EB01-49C1-9B69-8BF670841C5E}\1.0\
HELPDIR
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Interface\{43FC2C3D-A54B-45CB-803A-8D81635CB7BE}
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Interface\{43FC2C3D-A54B-45CB-803A-8D81635CB7BE}\ProxyStubClsid
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Interface\{43FC2C3D-A54B-45CB-803A-8D81635CB7BE}\ProxyStubClsid32
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Interface\{43FC2C3D-A54B-45CB-803A-8D81635CB7BE}\TypeLib
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Interface\{3AE1DC6D-FE15-4708-9C33-AB55C584F962}
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Interface\{3AE1DC6D-FE15-4708-9C33-AB55C584F962}\ProxyStubClsid
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Interface\{3AE1DC6D-FE15-4708-9C33-AB55C584F962}\ProxyStubClsid32
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Interface\{3AE1DC6D-FE15-4708-9C33-AB55C584F962}\TypeLib
HKEY_CLASSES_ROOT\CLSID\{3352A613-4939-47D7-91EF-DCC7120ADFA9}\
InProcServer32
HKEY_CLASSES_ROOT\CLSID\{BF08B5EB-5C61-42F2-8CED-C6BAD080CD95}\
InProcServer32
HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows\CurrentVersion\Uninstall\
WebVideo
It adds the following registry entries:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Internet Explorer\Toolbar
{72B68A1C-58DD-41B5-B619-D78A182A77D9} = "{random values}"
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{72B68A1C-58DD-41B5-B619-D78A182A77D9}\InprocServer32
ThreadingModel = "Apartment"
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Interface\{61E35336-39DD-46AD-B7DA-172A4E6CAC3B}\TypeLib
Version = "1.0"
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{AA890517-C937-403F-800F-C319A8406565}\InprocServer32
ThreadingModel = "Apartment"
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Interface\{43FC2C3D-A54B-45CB-803A-8D81635CB7BE}\TypeLib
Version = "1.0"
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Interface\{3AE1DC6D-FE15-4708-9C33-AB55C584F962}\TypeLib
Version = "1.0"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\ShellServiceObjectDelayLoad
xokvrpwg = "{3352A613-4939-47D7-91EF-DCC7120ADFA9}"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\ShellServiceObjectDelayLoad
tfnslopk = "{BF08B5EB-5C61-42F2-8CED-C6BAD080CD95}"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
WebVideo
uninstallString = "%Windows%\lnvegaow.exe"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
WebVideo
DisplayName = "WebVideo Support"
Dropping Routine
This Trojan drops the following files:
- %User Temp%\nsf2.tmp
- %User Temp%\nsf3.tmp\blowfish.dll
- %User Temp%\ac8zt2\wnlmdakqkpm.dll
- %User Temp%\ac8zt2\bgrqfetx.dll
- %User Temp%\ac8zt2\xokvrpwg.dll
- %User Temp%\ac8zt2\lnvegaow.exe
- %User Temp%\ac8zt2\eekf.exe
- %User Temp%\ac8zt2\tfnslopk.dll
- %User Temp%\nsf3.tmp\System.dll
- %Windows%\bgrqfetx.dll
- %Windows%\tfnslopk.dll
- %Windows%\lnvegaow.exe
- %Windows%\xokvrpwg.dll
- %Windows%\wnlmdakqkpm.dll
- %Windows%\eekf.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.. %Windows% is the Windows folder, which is usually C:\Windows.)
This report is generated via an automated analysis system.
SOLUTION
9.300
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
Close all opened browser windows
Step 3
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_CLASSES_ROOT
- bgrqfetx.ToolBar.1
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\bgrqfetx.ToolBar.1
- CLSID
- In HKEY_CLASSES_ROOT
- bgrqfetx.bdbn
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\bgrqfetx.bdbn
- CLSID
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\bgrqfetx.bdbn
- CurVer
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID
- {72B68A1C-58DD-41B5-B619-D78A182A77D9}
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{72B68A1C-58DD-41B5-B619-D78A182A77D9}
- ProgID
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{72B68A1C-58DD-41B5-B619-D78A182A77D9}
- VersionIndependentProgID
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{72B68A1C-58DD-41B5-B619-D78A182A77D9}
- Programmable
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{72B68A1C-58DD-41B5-B619-D78A182A77D9}
- InprocServer32
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{72B68A1C-58DD-41B5-B619-D78A182A77D9}
- TypeLib
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\TypeLib
- {25DC337D-A3EA-4D03-AC84-F89F5B0C461D}
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\TypeLib\{25DC337D-A3EA-4D03-AC84-F89F5B0C461D}
- 1.0
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\TypeLib\{25DC337D-A3EA-4D03-AC84-F89F5B0C461D}\1.0
- FLAGS
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\TypeLib\{25DC337D-A3EA-4D03-AC84-F89F5B0C461D}\1.0
- 0
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\TypeLib\{25DC337D-A3EA-4D03-AC84-F89F5B0C461D}\1.0\0
- win32
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\TypeLib\{25DC337D-A3EA-4D03-AC84-F89F5B0C461D}\1.0
- HELPDIR
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Interface
- {61E35336-39DD-46AD-B7DA-172A4E6CAC3B}
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Interface\{61E35336-39DD-46AD-B7DA-172A4E6CAC3B}
- ProxyStubClsid
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Interface\{61E35336-39DD-46AD-B7DA-172A4E6CAC3B}
- ProxyStubClsid32
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Interface\{61E35336-39DD-46AD-B7DA-172A4E6CAC3B}
- TypeLib
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer
- Browser Helper Objects
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID
- {AA890517-C937-403F-800F-C319A8406565}
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{AA890517-C937-403F-800F-C319A8406565}
- ProgID
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{AA890517-C937-403F-800F-C319A8406565}
- VersionIndependentProgID
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{AA890517-C937-403F-800F-C319A8406565}
- Programmable
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{AA890517-C937-403F-800F-C319A8406565}
- InprocServer32
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{AA890517-C937-403F-800F-C319A8406565}
- TypeLib
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\TypeLib
- {0291E0A0-EB01-49C1-9B69-8BF670841C5E}
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\TypeLib\{0291E0A0-EB01-49C1-9B69-8BF670841C5E}
- 1.0
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\TypeLib\{0291E0A0-EB01-49C1-9B69-8BF670841C5E}\1.0
- FLAGS
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\TypeLib\{0291E0A0-EB01-49C1-9B69-8BF670841C5E}\1.0
- 0
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\TypeLib\{0291E0A0-EB01-49C1-9B69-8BF670841C5E}\1.0\0
- win32
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\TypeLib\{0291E0A0-EB01-49C1-9B69-8BF670841C5E}\1.0
- HELPDIR
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Interface
- {43FC2C3D-A54B-45CB-803A-8D81635CB7BE}
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Interface\{43FC2C3D-A54B-45CB-803A-8D81635CB7BE}
- ProxyStubClsid
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Interface\{43FC2C3D-A54B-45CB-803A-8D81635CB7BE}
- ProxyStubClsid32
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Interface\{43FC2C3D-A54B-45CB-803A-8D81635CB7BE}
- TypeLib
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Interface
- {3AE1DC6D-FE15-4708-9C33-AB55C584F962}
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Interface\{3AE1DC6D-FE15-4708-9C33-AB55C584F962}
- ProxyStubClsid
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Interface\{3AE1DC6D-FE15-4708-9C33-AB55C584F962}
- ProxyStubClsid32
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Interface\{3AE1DC6D-FE15-4708-9C33-AB55C584F962}
- TypeLib
- In HKEY_CLASSES_ROOT\CLSID\{3352A613-4939-47D7-91EF-DCC7120ADFA9}
- InProcServer32
- In HKEY_CLASSES_ROOT\CLSID\{BF08B5EB-5C61-42F2-8CED-C6BAD080CD95}
- InProcServer32
- In HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Uninstall
- WebVideo
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_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\Toolbar
- {72B68A1C-58DD-41B5-B619-D78A182A77D9} = "{random values}"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{72B68A1C-58DD-41B5-B619-D78A182A77D9}\InprocServer32
- ThreadingModel = "Apartment"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Interface\{61E35336-39DD-46AD-B7DA-172A4E6CAC3B}\TypeLib
- Version = "1.0"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{AA890517-C937-403F-800F-C319A8406565}\InprocServer32
- ThreadingModel = "Apartment"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Interface\{43FC2C3D-A54B-45CB-803A-8D81635CB7BE}\TypeLib
- Version = "1.0"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Interface\{3AE1DC6D-FE15-4708-9C33-AB55C584F962}\TypeLib
- Version = "1.0"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\ShellServiceObjectDelayLoad
- xokvrpwg = "{3352A613-4939-47D7-91EF-DCC7120ADFA9}"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\ShellServiceObjectDelayLoad
- tfnslopk = "{BF08B5EB-5C61-42F2-8CED-C6BAD080CD95}"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\WebVideo
- uninstallString = "%Windows%\lnvegaow.exe"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\WebVideo
- DisplayName = "WebVideo Support"
Step 5
Search and delete these components
- %User Temp%\nsf2.tmp
- %User Temp%\nsf3.tmp\blowfish.dll
- %User Temp%\ac8zt2\wnlmdakqkpm.dll
- %User Temp%\ac8zt2\bgrqfetx.dll
- %User Temp%\ac8zt2\xokvrpwg.dll
- %User Temp%\ac8zt2\lnvegaow.exe
- %User Temp%\ac8zt2\eekf.exe
- %User Temp%\ac8zt2\tfnslopk.dll
- %User Temp%\nsf3.tmp\System.dll
- %Windows%\bgrqfetx.dll
- %Windows%\tfnslopk.dll
- %Windows%\lnvegaow.exe
- %Windows%\xokvrpwg.dll
- %Windows%\wnlmdakqkpm.dll
- %Windows%\eekf.exe
Step 6
Search and delete these folders
- %System Root%\DOCUME~1
- %System Root%\DOCUME~1\ADMINI~1
- %User Profile%\LOCALS~1
- %User Temp%\nsf3.tmp
- %User Temp%\ac8zt2
Step 7
Scan your computer with your Trend Micro product to delete files detected as TROJ_BHO.SK. 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 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.
- %User Temp%\nsf1.tmp
- %User Temp%\nsf3.tmp
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