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TROJ_VUNDO.SMF

April 08, 2013
 ALIASES:

Trojan:Win32/Vundo.gen!BC (Microsoft); Vundo.gen.ab (McAfee); Packed.Vuntid!gen1 (Symantec); Packed.Win32.Krap.q (Kaspersky); Trojan.Crypt.Krap (v) (Sunbelt); Win32/Cryptor (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:

47,616 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

08 Apr 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.

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
jawisesoza = "Rundll32.exe %System%\giveyaha.dll,s"

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\{8f24f5d9-00a0-40d5-a7d7-67206da90127}

Other System Modifications

This Trojan deletes the following files:

  • %System%\woruwiva.dll
  • %System%\dobokehi.dll
  • %System%\deyagehu.dll
  • %System%\pihuzura.dll
  • %System%\mrt.exe

(Note: %System% is the Windows system folder, which is usually C:\Windows\System32.)

It adds the following registry keys:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
sezavime

HKEY_CLASSES_ROOT\CLSID\{8f24f5d9-00a0-40d5-a7d7-67206da90127}

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{8f24f5d9-00a0-40d5-a7d7-67206da90127}\InprocServer32

It adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
sezavime
savemimi = "{random values}"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Windows
LoadAppInit_DLLs = "1"

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{8f24f5d9-00a0-40d5-a7d7-67206da90127}\InprocServer32
ThreadingModel = "Both"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\AuthorizedApplications\
List
%Windows%\explorer.exe = "%Windows%\explorer.exe:*:Enabled:Explorer"

It modifies the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Windows
AppInit_DLLs = "%System%\nedoyita.dll"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Control\Lsa
Notification Packages = "scecli,%System%\nedoyita.dll"

(Note: The default value data of the said registry entry is {random values}.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center
UpdatesDisableNotify = "1"

It deletes the following registry keys:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Ext\
Settings\{8f24f5d9-00a0-40d5-a7d7-67206da90127}

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_LOCAL_MACHINE\SOFTWARE\Microsoft
    • sezavime
  • In HKEY_CLASSES_ROOT\CLSID
    • {8f24f5d9-00a0-40d5-a7d7-67206da90127}
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{8f24f5d9-00a0-40d5-a7d7-67206da90127}
    • InprocServer32

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
    • jawisesoza = "Rundll32.exe %System%\giveyaha.dll,s"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\sezavime
    • savemimi = "{random values}"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Windows
    • LoadAppInit_DLLs = "1"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{8f24f5d9-00a0-40d5-a7d7-67206da90127}\InprocServer32
    • ThreadingModel = "Both"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\AuthorizedApplications\List
    • %Windows%\explorer.exe = "%Windows%\explorer.exe:*:Enabled:Explorer"

Step 6

Restore these modified registry values

[ Learn More ]

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 = "%System%\nedoyita.dll"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\Lsa
    • From: Notification Packages = "scecli,%System%\nedoyita.dll"
      To: Notification Packages = ""{random values}""
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center
    • UpdatesDisableNotify = "1"

Step 7

Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_VUNDO.SMF. 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.

  • %System%\woruwiva.dll
  • %System%\dobokehi.dll
  • %System%\deyagehu.dll
  • %System%\pihuzura.dll
  • %System%\mrt.exe

Step 9

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_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Ext\Settings
    • {8f24f5d9-00a0-40d5-a7d7-67206da90127}


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