ALIASES:

Worm:Win32/Wenper.B (Microsoft); W32/Wenper.worm.gen (McAfee); W32.Wenper.Worm (Symantec); Worm.Win32.Wenper.b (Kaspersky); Worm.Win32.Wenper.b (v) (Sunbelt); Worm/Wenper.C (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: 157,696 bytes
File Type: EXE
Memory Resident: No
Initial Samples Received Date: 09 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.

Other System Modifications

This Trojan adds the following registry keys:

HKEY_CLASSES_ROOT\CLSID\{310DE29C-0AD3-4A43-A2DB-221F1160CACB}

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{310DE29C-0AD3-4A43-A2DB-221F1160CACB}\InprocServer32

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{310DE29C-0AD3-4A43-A2DB-221F1160CACB}\ProgID

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{310DE29C-0AD3-4A43-A2DB-221F1160CACB}\VersionIndependentProgID

HKEY_CLASSES_ROOT\WinCryptography.Encrypt

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
WinCryptography.Encrypt\CLSID

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
WinCryptography.Encrypt\CurVer

HKEY_CLASSES_ROOT\WinCryptography.Encrypt.1

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
WinCryptography.Encrypt.1\CLSID

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon\
Notify\wlogon

It adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{310DE29C-0AD3-4A43-A2DB-221F1160CACB}\InprocServer32
ThreadingModel = "Both"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon\
Notify\wlogon
Asynchronous = "1"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon\
Notify\wlogon
Impersonate = "1"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon\
Notify\wlogon
Logon = "EvWinLogon"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon\
Notify\wlogon
Startup = "EvWinLogon"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon\
Notify\wlogon
StartShell = "EvWinLogon"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon\
Notify\wlogon
DLLName = "wlogon.dll"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\Lcss
Description = "???????????? ????????? ??????? ? ???????????? ????????? ???????????? ???????????."

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

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_CLASSES_ROOT\CLSID
    • {310DE29C-0AD3-4A43-A2DB-221F1160CACB}
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{310DE29C-0AD3-4A43-A2DB-221F1160CACB}
    • InprocServer32
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{310DE29C-0AD3-4A43-A2DB-221F1160CACB}
    • ProgID
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{310DE29C-0AD3-4A43-A2DB-221F1160CACB}
    • VersionIndependentProgID
  • In HKEY_CLASSES_ROOT
    • WinCryptography.Encrypt
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\WinCryptography.Encrypt
    • CLSID
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\WinCryptography.Encrypt
    • CurVer
  • In HKEY_CLASSES_ROOT
    • WinCryptography.Encrypt.1
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\WinCryptography.Encrypt.1
    • CLSID
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon\Notify
    • wlogon

Step 3

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\Classes\CLSID\{310DE29C-0AD3-4A43-A2DB-221F1160CACB}\InprocServer32
    • ThreadingModel = "Both"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon\Notify\wlogon
    • Asynchronous = "1"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon\Notify\wlogon
    • Impersonate = "1"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon\Notify\wlogon
    • Logon = "EvWinLogon"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon\Notify\wlogon
    • Startup = "EvWinLogon"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon\Notify\wlogon
    • StartShell = "EvWinLogon"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon\Notify\wlogon
    • DLLName = "wlogon.dll"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\Lcss
    • Description = "???????????? ????????? ??????? ? ???????????? ????????? ???????????? ???????????."

Step 4

Scan your computer with your Trend Micro product to delete files detected as TROJ_MALNID.A. 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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