TROJ_DROPPR.MPS


 ALIASES:

TrojanDropper:Win32/Umrena.F (Microsoft); [00025a10.EXE]:Generic Dropper!1ej (McAfee); Trojan.Gen.2 (Symantec); Trojan-Downloader.Win32.Agent.tfzo (Kaspersky); Trojan.Win32.Generic.pak!cobra (Sunbelt); Trojan.Generic.6662246 (FSecure)

 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:

374,272 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

27 Apr 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 drops the following copies of itself into the affected system:

  • %Windows%\wscript32.exe

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

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
wscript32 = "%Windows%\wscript32.exe hold09-14"

Other System Modifications

This Trojan adds the following registry keys:

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
TypeLib\{B58ED2B9-9069-43A7-97B6-B1D239C875CD}

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
TypeLib\{B58ED2B9-9069-43A7-97B6-B1D239C875CD}\1.0

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
TypeLib\{B58ED2B9-9069-43A7-97B6-B1D239C875CD}\1.0\
FLAGS

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
TypeLib\{B58ED2B9-9069-43A7-97B6-B1D239C875CD}\1.0\
0

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
TypeLib\{B58ED2B9-9069-43A7-97B6-B1D239C875CD}\1.0\
0\win32

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
TypeLib\{B58ED2B9-9069-43A7-97B6-B1D239C875CD}\1.0\
HELPDIR

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Interface\{B2EC114F-6A65-4D63-815A-FFBA0C2F6E57}

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Interface\{B2EC114F-6A65-4D63-815A-FFBA0C2F6E57}\ProxyStubClsid

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Interface\{B2EC114F-6A65-4D63-815A-FFBA0C2F6E57}\ProxyStubClsid32

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Interface\{B2EC114F-6A65-4D63-815A-FFBA0C2F6E57}\TypeLib

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Interface\{75F73169-3459-40E0-A699-E63EC28147EC}

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Interface\{75F73169-3459-40E0-A699-E63EC28147EC}\ProxyStubClsid

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Interface\{75F73169-3459-40E0-A699-E63EC28147EC}\ProxyStubClsid32

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Interface\{75F73169-3459-40E0-A699-E63EC28147EC}\TypeLib

HKEY_CLASSES_ROOT\CLSID\{30D3C5D0-AB43-4169-8381-B225058083A7}

HKEY_CLASSES_ROOT\CLSID\{30D3C5D0-AB43-4169-8381-B225058083A7}\
InprocServer32

HKEY_CLASSES_ROOT\wbhelper.wbtools

HKEY_CLASSES_ROOT\wbhelper.wbtools\Clsid

HKEY_CLASSES_ROOT\CLSID\{30D3C5D0-AB43-4169-8381-B225058083A7}\
ProgID

HKEY_CLASSES_ROOT\CLSID\{30D3C5D0-AB43-4169-8381-B225058083A7}\
Version

HKEY_CLASSES_ROOT\CLSID\{30D3C5D0-AB43-4169-8381-B225058083A7}\
TypeLib

HKEY_CLASSES_ROOT\CLSID\{30D3C5D0-AB43-4169-8381-B225058083A7}\
MiscStatus

HKEY_CLASSES_ROOT\CLSID\{30D3C5D0-AB43-4169-8381-B225058083A7}\
MiscStatus\1

HKEY_CLASSES_ROOT\CLSID\{30D3C5D0-AB43-4169-8381-B225058083A7}\
ToolboxBitmap32

HKEY_CLASSES_ROOT\CLSID\{30D3C5D0-AB43-4169-8381-B225058083A7}\
Control

HKEY_CLASSES_ROOT\CLSID\{30D3C5D0-AB43-4169-8381-B225058083A7}\
Verb

HKEY_CLASSES_ROOT\CLSID\{30D3C5D0-AB43-4169-8381-B225058083A7}\
Verb\0

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\International\CpMRU

It adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Interface\{B2EC114F-6A65-4D63-815A-FFBA0C2F6E57}\TypeLib
Version = "1.0"

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Interface\{75F73169-3459-40E0-A699-E63EC28147EC}\TypeLib
Version = "1.0"

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{30D3C5D0-AB43-4169-8381-B225058083A7}\InprocServer32
ThreadingModel = "Apartment"

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\International\CpMRU
Enable = "1"

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\International\CpMRU
Size = "a"

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\International\CpMRU
InitHits = "64"

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\International\CpMRU
Factor = "14"

It modifies the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings\
Zones\0
1601 = "0"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings\
Zones\1
1601 = "0"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings\
Zones\2
1601 = "0"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings\
Zones\3
1601 = "0"

(Note: The default value data of the said registry entry is 1.)

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings\
Zones\4
1601 = "0"

(Note: The default value data of the said registry entry is 1.)

It deletes the following registry keys:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Internet Settings\
User Agent\Post Platform

Dropping Routine

This Trojan drops the following files:

  • %Windows%\wbhelper.ocx
  • %User Profile%\localprofile.vbs

(Note: %Windows% is the Windows folder, which is usually C:\Windows or C:\WINNT.. %User Profile% is the current user's profile folder, which is usually C:\Windows\Profiles\{user name} on Windows 98 and ME, C:\WINNT\Profiles\{user name} on Windows NT, and C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003.)

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine:

9.200

Step 1

For Windows XP and Windows Server 2003 users, before doing any scans, please make sure you disable System Restore to allow full scanning of your computer.

Step 2

Restart in Safe Mode

[ Learn More ]

Step 3

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_LOCAL_MACHINE\SOFTWARE\Classes\TypeLib
    • {B58ED2B9-9069-43A7-97B6-B1D239C875CD}
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\TypeLib\{B58ED2B9-9069-43A7-97B6-B1D239C875CD}
    • 1.0
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\TypeLib\{B58ED2B9-9069-43A7-97B6-B1D239C875CD}\1.0
    • FLAGS
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\TypeLib\{B58ED2B9-9069-43A7-97B6-B1D239C875CD}\1.0
    • 0
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\TypeLib\{B58ED2B9-9069-43A7-97B6-B1D239C875CD}\1.0\0
    • win32
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\TypeLib\{B58ED2B9-9069-43A7-97B6-B1D239C875CD}\1.0
    • HELPDIR
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Interface
    • {B2EC114F-6A65-4D63-815A-FFBA0C2F6E57}
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Interface\{B2EC114F-6A65-4D63-815A-FFBA0C2F6E57}
    • ProxyStubClsid
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Interface\{B2EC114F-6A65-4D63-815A-FFBA0C2F6E57}
    • ProxyStubClsid32
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Interface\{B2EC114F-6A65-4D63-815A-FFBA0C2F6E57}
    • TypeLib
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Interface
    • {75F73169-3459-40E0-A699-E63EC28147EC}
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Interface\{75F73169-3459-40E0-A699-E63EC28147EC}
    • ProxyStubClsid
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Interface\{75F73169-3459-40E0-A699-E63EC28147EC}
    • ProxyStubClsid32
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Interface\{75F73169-3459-40E0-A699-E63EC28147EC}
    • TypeLib
  • In HKEY_CLASSES_ROOT\CLSID
    • {30D3C5D0-AB43-4169-8381-B225058083A7}
  • In HKEY_CLASSES_ROOT\CLSID\{30D3C5D0-AB43-4169-8381-B225058083A7}
    • InprocServer32
  • In HKEY_CLASSES_ROOT
    • wbhelper.wbtools
  • In HKEY_CLASSES_ROOT\wbhelper.wbtools
    • Clsid
  • In HKEY_CLASSES_ROOT\CLSID\{30D3C5D0-AB43-4169-8381-B225058083A7}
    • ProgID
  • In HKEY_CLASSES_ROOT\CLSID\{30D3C5D0-AB43-4169-8381-B225058083A7}
    • Version
  • In HKEY_CLASSES_ROOT\CLSID\{30D3C5D0-AB43-4169-8381-B225058083A7}
    • TypeLib
  • In HKEY_CLASSES_ROOT\CLSID\{30D3C5D0-AB43-4169-8381-B225058083A7}
    • MiscStatus
  • In HKEY_CLASSES_ROOT\CLSID\{30D3C5D0-AB43-4169-8381-B225058083A7}\MiscStatus
    • 1
  • In HKEY_CLASSES_ROOT\CLSID\{30D3C5D0-AB43-4169-8381-B225058083A7}
    • ToolboxBitmap32
  • In HKEY_CLASSES_ROOT\CLSID\{30D3C5D0-AB43-4169-8381-B225058083A7}
    • Control
  • In HKEY_CLASSES_ROOT\CLSID\{30D3C5D0-AB43-4169-8381-B225058083A7}
    • Verb
  • In HKEY_CLASSES_ROOT\CLSID\{30D3C5D0-AB43-4169-8381-B225058083A7}\Verb
    • 0
  • In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\International
    • CpMRU

Step 4

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_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • wscript32 = "%Windows%\wscript32.exe hold09-14"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Interface\{B2EC114F-6A65-4D63-815A-FFBA0C2F6E57}\TypeLib
    • Version = "1.0"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Interface\{75F73169-3459-40E0-A699-E63EC28147EC}\TypeLib
    • Version = "1.0"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{30D3C5D0-AB43-4169-8381-B225058083A7}\InprocServer32
    • ThreadingModel = "Apartment"
  • In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\International\CpMRU
    • Enable = "1"
  • In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\International\CpMRU
    • Size = "a"
  • In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\International\CpMRU
    • InitHits = "64"
  • In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\International\CpMRU
    • Factor = "14"

Step 5

Restore this modified 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_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Zones\0
    • 1601 = "0"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Zones\1
    • 1601 = "0"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Zones\2
    • 1601 = "0"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Zones\3
    • From: 1601 = "0"
      To: 1601 = ""1""
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Zones\4
    • From: 1601 = "0"
      To: 1601 = ""1""

Step 6

Search and delete these files

[ Learn More ]
There may be some component files 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%\wbhelper.ocx
  • %User Profile%\localprofile.vbs

Step 7

Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_DROPPR.MPS. 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 these deleted registry keys/values from backup

*Note: Only Microsoft-related keys/values will be restored. If the malware/grayware also deleted registry keys/values related to programs that are not from Microsoft, please reinstall those programs on your computer.

  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Internet Settings\User Agent
    • Post Platform


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