TROJ_DROPPR.BH
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.
It deletes itself after execution.
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 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\{E9C0568A-0146-9ACE-2347-9ACE13568ABD}
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Explorer\
Browser Helper Objects\{6E28339B-7A2A-47B6-AEB2-46BA53782379}
HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Browser Helper Objects\{E92B03AB-A707-11d2-9CBD-0000F87A369H}
Other System Modifications
This Trojan adds the following registry keys:
HKEY_CLASSES_ROOT\CLSID\{E9C0568A-0146-9ACE-2347-9ACE13568ABD}\
InprocServer32
HKEY_CLASSES_ROOT\BhoPlugin.EyeOnIE.1
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
BhoPlugin.EyeOnIE.1\CLSID
HKEY_CLASSES_ROOT\BhoPlugin.EyeOnIE
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
BhoPlugin.EyeOnIE\CLSID
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
BhoPlugin.EyeOnIE\CurVer
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{6E28339B-7A2A-47B6-AEB2-46BA53782379}
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{6E28339B-7A2A-47B6-AEB2-46BA53782379}\ProgID
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{6E28339B-7A2A-47B6-AEB2-46BA53782379}\VersionIndependentProgID
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{6E28339B-7A2A-47B6-AEB2-46BA53782379}\Programmable
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{6E28339B-7A2A-47B6-AEB2-46BA53782379}\InprocServer32
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{6E28339B-7A2A-47B6-AEB2-46BA53782379}\TypeLib
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
TypeLib\{A2D5957F-6D1A-44CE-BFBA-D448EAAB8781}
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
TypeLib\{A2D5957F-6D1A-44CE-BFBA-D448EAAB8781}\1.0
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
TypeLib\{A2D5957F-6D1A-44CE-BFBA-D448EAAB8781}\1.0\
FLAGS
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
TypeLib\{A2D5957F-6D1A-44CE-BFBA-D448EAAB8781}\1.0\
0
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
TypeLib\{A2D5957F-6D1A-44CE-BFBA-D448EAAB8781}\1.0\
0\win32
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
TypeLib\{A2D5957F-6D1A-44CE-BFBA-D448EAAB8781}\1.0\
HELPDIR
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Interface\{4CF9A0D2-ED75-40CB-98C0-36DF6A30E040}
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Interface\{4CF9A0D2-ED75-40CB-98C0-36DF6A30E040}\ProxyStubClsid
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Interface\{4CF9A0D2-ED75-40CB-98C0-36DF6A30E040}\ProxyStubClsid32
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Interface\{4CF9A0D2-ED75-40CB-98C0-36DF6A30E040}\TypeLib
HKEY_CLASSES_ROOT\CLSID\{E92B03AB-A707-11d2-9CBD-0000F87A369H}\
InprocServer32
It adds the following registry entries:
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{6E28339B-7A2A-47B6-AEB2-46BA53782379}\InprocServer32
ThreadingModel = "Apartment"
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Interface\{4CF9A0D2-ED75-40CB-98C0-36DF6A30E040}\TypeLib
Version = "1.0"
It modifies the following registry entries:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Windows
AppInit_DLLs = "Windows32"
Dropping Routine
This Trojan drops the following files:
- %System%\Windows32.dll
(Note: %System% is the Windows system folder, which is usually C:\Windows\System32.)
Other Details
This Trojan deletes itself after execution.
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
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\CLSID\{E9C0568A-0146-9ACE-2347-9ACE13568ABD}
- InprocServer32
- In HKEY_CLASSES_ROOT
- BhoPlugin.EyeOnIE.1
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\BhoPlugin.EyeOnIE.1
- CLSID
- In HKEY_CLASSES_ROOT
- BhoPlugin.EyeOnIE
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\BhoPlugin.EyeOnIE
- CLSID
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\BhoPlugin.EyeOnIE
- CurVer
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID
- {6E28339B-7A2A-47B6-AEB2-46BA53782379}
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{6E28339B-7A2A-47B6-AEB2-46BA53782379}
- ProgID
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{6E28339B-7A2A-47B6-AEB2-46BA53782379}
- VersionIndependentProgID
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{6E28339B-7A2A-47B6-AEB2-46BA53782379}
- Programmable
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{6E28339B-7A2A-47B6-AEB2-46BA53782379}
- InprocServer32
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{6E28339B-7A2A-47B6-AEB2-46BA53782379}
- TypeLib
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\TypeLib
- {A2D5957F-6D1A-44CE-BFBA-D448EAAB8781}
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\TypeLib\{A2D5957F-6D1A-44CE-BFBA-D448EAAB8781}
- 1.0
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\TypeLib\{A2D5957F-6D1A-44CE-BFBA-D448EAAB8781}\1.0
- FLAGS
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\TypeLib\{A2D5957F-6D1A-44CE-BFBA-D448EAAB8781}\1.0
- 0
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\TypeLib\{A2D5957F-6D1A-44CE-BFBA-D448EAAB8781}\1.0\0
- win32
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\TypeLib\{A2D5957F-6D1A-44CE-BFBA-D448EAAB8781}\1.0
- HELPDIR
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Interface
- {4CF9A0D2-ED75-40CB-98C0-36DF6A30E040}
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Interface\{4CF9A0D2-ED75-40CB-98C0-36DF6A30E040}
- ProxyStubClsid
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Interface\{4CF9A0D2-ED75-40CB-98C0-36DF6A30E040}
- ProxyStubClsid32
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Interface\{4CF9A0D2-ED75-40CB-98C0-36DF6A30E040}
- TypeLib
- In HKEY_CLASSES_ROOT\CLSID\{E92B03AB-A707-11d2-9CBD-0000F87A369H}
- InprocServer32
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\Classes\CLSID\{6E28339B-7A2A-47B6-AEB2-46BA53782379}\InprocServer32
- ThreadingModel = "Apartment"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Interface\{4CF9A0D2-ED75-40CB-98C0-36DF6A30E040}\TypeLib
- Version = "1.0"
Step 5
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_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Windows
- AppInit_DLLs = "Windows32"
Step 6
Search and delete this file
- %System%\Windows32.dll
Step 7
Scan your computer with your Trend Micro product to delete files detected as TROJ_DROPPR.BH. 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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