ALIASES:

Trojan:Win32/Provis!rts, Trojan:Win32/Bumat!rts, Trojan:Win32/Provis!rts (Microsoft); [0000ec0c.EXE]:Generic.dx!0479F265A2BF, [00023c0c.EXE]:BackDoor-EWB (McAfee); Trojan-Dropper.Win32.VB.amma (Kaspersky); Trojan.Win32.Generic.pak!cobra (Sunbelt); Trojan horse Generic17.HWS (AVG)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

 OVERALL RISK RATING:
 DAMAGE POTENTIAL:
 DISTRIBUTION POTENTIAL:
 REPORTED INFECTION:

  • 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

File Size: 71,168 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 14 May 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 creates the following folders:

  • %Windows%\Maxthon

(Note: %Windows% is the Windows folder, which is usually C:\Windows.)

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
smss = "%Windows%\maxthon\smss.exe"

It 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\{CE6F4304-993F-4AA1-B56E-8F2B112B5E8A}

Other System Modifications

This Trojan modifies the following file(s):

  • %Start Menu%\Programs\Internet Explorer.lnk

(Note: %Start Menu% is the current user's Start Menu folder, which is usually C:\Windows\Start Menu or C:\Documents and Settings\{User name}\Start Menu on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Roaming\Microsoft\Windows\Start Menu on Windows Vista and 7.)

It adds the following registry keys:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
HideDesktopIcons\NewStartPanel

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
HideDesktopIcons\ClassicStartMenu

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Explorer\
Desktop\NameSpace\{871C5380-42A0-1069-A2EA-08002B30309A}

HKEY_CLASSES_ROOT\CLSID\{871C5380-42A0-1069-A2EA-08002B30309A}

HKEY_CLASSES_ROOT\CLSID\{871C5380-42A0-1069-A2EA-08002B30309A}\
DefaultIcon

HKEY_CLASSES_ROOT\CLSID\{871C5380-42A0-1069-A2EA-08002B30309A}\
InProcServer32

HKEY_CLASSES_ROOT\CLSID\{871C5380-42A0-1069-A2EA-08002B30309A}\
Shell

HKEY_CLASSES_ROOT\CLSID\{871C5380-42A0-1069-A2EA-08002B30309A}\
Shell\OpenHomePage

HKEY_CLASSES_ROOT\CLSID\{871C5380-42A0-1069-A2EA-08002B30309A}\
Shell\OpenHomePage\Command

HKEY_CLASSES_ROOT\CLSID\{871C5380-42A0-1069-A2EA-08002B30309A}\
Shell\Q

HKEY_CLASSES_ROOT\CLSID\{871C5380-42A0-1069-A2EA-08002B30309A}\
Shell\Q\Command

HKEY_CLASSES_ROOT\CLSID\{871C5380-42A0-1069-A2EA-08002B30309A}\
Shell\??(&R)

HKEY_CLASSES_ROOT\CLSID\{871C5380-42A0-1069-A2EA-08002B30309A}\
Shell\??(&R)\Command

HKEY_CLASSES_ROOT\CLSID\{871C5380-42A0-1069-A2EA-08002B30309A}\
ShellFolder

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
TypeLib\{194D2970-A9B4-4C9C-8BC3-E2D710BAB284}

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
TypeLib\{194D2970-A9B4-4C9C-8BC3-E2D710BAB284}\1.0

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
TypeLib\{194D2970-A9B4-4C9C-8BC3-E2D710BAB284}\1.0\
FLAGS

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
TypeLib\{194D2970-A9B4-4C9C-8BC3-E2D710BAB284}\1.0\
0

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
TypeLib\{194D2970-A9B4-4C9C-8BC3-E2D710BAB284}\1.0\
0\win32

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
TypeLib\{194D2970-A9B4-4C9C-8BC3-E2D710BAB284}\1.0\
HELPDIR

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Interface\{6C754782-968E-4118-863B-0A057D3CF097}

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Interface\{6C754782-968E-4118-863B-0A057D3CF097}\ProxyStubClsid

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Interface\{6C754782-968E-4118-863B-0A057D3CF097}\ProxyStubClsid32

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Interface\{6C754782-968E-4118-863B-0A057D3CF097}\TypeLib

HKEY_CLASSES_ROOT\CLSID\{CE6F4304-993F-4AA1-B56E-8F2B112B5E8A}

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{CE6F4304-993F-4AA1-B56E-8F2B112B5E8A}\InprocServer32

HKEY_CLASSES_ROOT\XunLeiAdBlocker.XunLeiBlock

It adds the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
HideDesktopIcons\NewStartPanel
{871C5380-42A0-1069-A2EA-08002B30309D} = "1"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
HideDesktopIcons\ClassicStartMenu
{871C5380-42A0-1069-A2EA-08002B30309D} = "1"

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{871C5380-42A0-1069-A2EA-08002B30309A}\ShellFolder
Attributes = "{random values}"

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Interface\{6C754782-968E-4118-863B-0A057D3CF097}\TypeLib
Version = "1.0"

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{CE6F4304-993F-4AA1-B56E-8F2B112B5E8A}
ProgID = "XunLeiAdBlocker.XunLeiBlock"

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{CE6F4304-993F-4AA1-B56E-8F2B112B5E8A}\InprocServer32
ThreadingModel = "Apartment"

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{CE6F4304-993F-4AA1-B56E-8F2B112B5E8A}
TypeLib = "{194D2970-A9B4-4C9C-8BC3-E2D710BAB284}"

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{CE6F4304-993F-4AA1-B56E-8F2B112B5E8A}
VERSION = "1.0"

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
XunLeiAdBlocker.XunLeiBlock
Clsid = "{CE6F4304-993F-4AA1-B56E-8F2B112B5E8A}"

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Interface\{6C754782-968E-4118-863B-0A057D3CF097}
ProxyStubClsid = "{00020424-0000-0000-C000-000000000046}"

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Interface\{6C754782-968E-4118-863B-0A057D3CF097}
ProxyStubClsid32 = "{00020424-0000-0000-C000-000000000046}"

Dropping Routine

This Trojan drops the following files:

  • %Windows%\StrongIndex.reg
  • %System%\reg.reg
  • %Favorites%\?????????-?Q?-????????.url
  • %Favorites%\????-?????.url
  • %Favorites%\??? - ?!???.url
  • %Favorites%\???? - ?????.url
  • %Favorites%\????.url
  • %Favorites%\????-?????????,?????!.url
  • %Desktop%\????.lnk
  • %Windows%\????.lnk
  • %Windows%\updateLnk.vbe
  • %User Startup%\open.vbe
  • %System%\del.bat
  • %User Profile%\Quick Launch\Launch Internet Explorer Browser.lnk
  • %Start Menu%\Windows Catalog.lnk
  • %Desktop%\Internet Explorer.lnk
  • %User Profile%\Quick Launch\Internet Explorer.lnk
  • %Program Files%\Internet Explorer\iexlore.exe
  • %Program Files%\Maxthon2\imaxthon.exe
  • %Program Files%\360\360se3\360s.exe
  • %Windows%\google.exe

(Note: %Windows% is the Windows folder, which is usually C:\Windows.. %System% is the Windows system folder, which is usually C:\Windows\System32.. %Favorites% is the current user's Favorites folder, which is usually C:\Documents and Settings\{user name}\Favorites on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\Favorites on Windows Vista and 7.. %Desktop% is the current user's desktop, which is usually C:\Documents and Settings\{User Name}\Desktop on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\Desktop on Windows Vista and 7.. %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.. %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.. %Start Menu% is the current user's Start Menu folder, which is usually C:\Windows\Start Menu or C:\Documents and Settings\{User name}\Start Menu on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Roaming\Microsoft\Windows\Start Menu 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).)

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine: 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

Restart in Safe Mode

[ Learn More ]

Step 3

Close all opened browser windows

Step 4

Delete this registry key

[ Learn More ]

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\Explorer\HideDesktopIcons
    • NewStartPanel
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\HideDesktopIcons
    • ClassicStartMenu
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Desktop\NameSpace
    • {871C5380-42A0-1069-A2EA-08002B30309A}
  • In HKEY_CLASSES_ROOT\CLSID
    • {871C5380-42A0-1069-A2EA-08002B30309A}
  • In HKEY_CLASSES_ROOT\CLSID\{871C5380-42A0-1069-A2EA-08002B30309A}
    • DefaultIcon
  • In HKEY_CLASSES_ROOT\CLSID\{871C5380-42A0-1069-A2EA-08002B30309A}
    • InProcServer32
  • In HKEY_CLASSES_ROOT\CLSID\{871C5380-42A0-1069-A2EA-08002B30309A}
    • Shell
  • In HKEY_CLASSES_ROOT\CLSID\{871C5380-42A0-1069-A2EA-08002B30309A}\Shell
    • OpenHomePage
  • In HKEY_CLASSES_ROOT\CLSID\{871C5380-42A0-1069-A2EA-08002B30309A}\Shell\OpenHomePage
    • Command
  • In HKEY_CLASSES_ROOT\CLSID\{871C5380-42A0-1069-A2EA-08002B30309A}\Shell
    • Q
  • In HKEY_CLASSES_ROOT\CLSID\{871C5380-42A0-1069-A2EA-08002B30309A}\Shell\Q
    • Command
  • In HKEY_CLASSES_ROOT\CLSID\{871C5380-42A0-1069-A2EA-08002B30309A}\Shell
    • ??(&R)
  • In HKEY_CLASSES_ROOT\CLSID\{871C5380-42A0-1069-A2EA-08002B30309A}\Shell\??(&R)
    • Command
  • In HKEY_CLASSES_ROOT\CLSID\{871C5380-42A0-1069-A2EA-08002B30309A}
    • ShellFolder
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\TypeLib
    • {194D2970-A9B4-4C9C-8BC3-E2D710BAB284}
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\TypeLib\{194D2970-A9B4-4C9C-8BC3-E2D710BAB284}
    • 1.0
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\TypeLib\{194D2970-A9B4-4C9C-8BC3-E2D710BAB284}\1.0
    • FLAGS
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\TypeLib\{194D2970-A9B4-4C9C-8BC3-E2D710BAB284}\1.0
    • 0
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\TypeLib\{194D2970-A9B4-4C9C-8BC3-E2D710BAB284}\1.0\0
    • win32
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\TypeLib\{194D2970-A9B4-4C9C-8BC3-E2D710BAB284}\1.0
    • HELPDIR
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Interface
    • {6C754782-968E-4118-863B-0A057D3CF097}
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Interface\{6C754782-968E-4118-863B-0A057D3CF097}
    • ProxyStubClsid
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Interface\{6C754782-968E-4118-863B-0A057D3CF097}
    • ProxyStubClsid32
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Interface\{6C754782-968E-4118-863B-0A057D3CF097}
    • TypeLib
  • In HKEY_CLASSES_ROOT\CLSID
    • {CE6F4304-993F-4AA1-B56E-8F2B112B5E8A}
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{CE6F4304-993F-4AA1-B56E-8F2B112B5E8A}
    • InprocServer32
  • In HKEY_CLASSES_ROOT
    • XunLeiAdBlocker.XunLeiBlock

Step 5

Delete this registry value

[ Learn More ]

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\Windows\CurrentVersion\Run
    • smss = "%Windows%\maxthon\smss.exe"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\HideDesktopIcons\NewStartPanel
    • {871C5380-42A0-1069-A2EA-08002B30309D} = "1"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\HideDesktopIcons\ClassicStartMenu
    • {871C5380-42A0-1069-A2EA-08002B30309D} = "1"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{871C5380-42A0-1069-A2EA-08002B30309A}\ShellFolder
    • Attributes = "{random values}"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Interface\{6C754782-968E-4118-863B-0A057D3CF097}\TypeLib
    • Version = "1.0"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{CE6F4304-993F-4AA1-B56E-8F2B112B5E8A}
    • ProgID = "XunLeiAdBlocker.XunLeiBlock"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{CE6F4304-993F-4AA1-B56E-8F2B112B5E8A}\InprocServer32
    • ThreadingModel = "Apartment"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{CE6F4304-993F-4AA1-B56E-8F2B112B5E8A}
    • TypeLib = "{194D2970-A9B4-4C9C-8BC3-E2D710BAB284}"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{CE6F4304-993F-4AA1-B56E-8F2B112B5E8A}
    • VERSION = "1.0"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\XunLeiAdBlocker.XunLeiBlock
    • Clsid = "{CE6F4304-993F-4AA1-B56E-8F2B112B5E8A}"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Interface\{6C754782-968E-4118-863B-0A057D3CF097}
    • ProxyStubClsid = "{00020424-0000-0000-C000-000000000046}"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Interface\{6C754782-968E-4118-863B-0A057D3CF097}
    • ProxyStubClsid32 = "{00020424-0000-0000-C000-000000000046}"

Step 6

Search and delete these components

[ Learn More ]
There may be some components that are hidden. Please make sure you check the Search Hidden Files and Folders checkbox in the "More advanced options" option to include all hidden files and folders in the search result.
  • %Windows%\StrongIndex.reg
  • %System%\reg.reg
  • %Favorites%\?????????-?Q?-????????.url
  • %Favorites%\????-?????.url
  • %Favorites%\??? - ?!???.url
  • %Favorites%\???? - ?????.url
  • %Favorites%\????.url
  • %Favorites%\????-?????????,?????!.url
  • %Desktop%\????.lnk
  • %Windows%\????.lnk
  • %Windows%\updateLnk.vbe
  • %User Startup%\open.vbe
  • %System%\del.bat
  • %User Profile%\Quick Launch\Launch Internet Explorer Browser.lnk
  • %Start Menu%\Windows Catalog.lnk
  • %Desktop%\Internet Explorer.lnk
  • %User Profile%\Quick Launch\Internet Explorer.lnk
  • %Program Files%\Internet Explorer\iexlore.exe
  • %Program Files%\Maxthon2\imaxthon.exe
  • %Program Files%\360\360se3\360s.exe
  • %Windows%\google.exe

Step 7

Search and delete this folder

[ Learn More ]
Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden folders in the search result.
  • %Windows%\Maxthon

Step 8

Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_VBCODE.AE. 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 9

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.

    • %Start Menu%\Programs\Internet Explorer.lnk


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