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Nome del virus:VBS/Small.Sasan.A
Scoperto:08/11/2007
Tipo:Worm
In circolazione (ITW):No
Numero delle infezioni segnalate:Basso
Potenziale di propagazione:Medio-Basso
Potenziale di danni:Medio-Basso
File statico:Si
Dimensione del file:10.164 Byte
Somma di controllo MD5:efe528483fd3c6ed75a8c1e016026e10
Versione VDF:7.00.00.185
Versione IVDF:7.00.00.192 - giovedì 8 novembre 2007

 Generale Metodo di propagazione:
   • Unitdi rete mappata


Alias:
   •  Sophos: VBS/Sasan-Fam
   •  Grisoft: VBS/LoveLetter


Piattaforme / Sistemi operativi:
   • Windows 95
   • Windows 98
   • Windows 98 SE
   • Windows NT
   • Windows ME
   • Windows 2000
   • Windows XP
   • Windows 2003


Effetti secondari:
   • Disattiva le applicazioni di sicurezza
   • Duplica un file
   • Modifica del registro


Giusto dopo l'esecuzione, avvia un'applicazione Windows che visualizzer la seguente finestra:





   Merlin: Huh..Banjarbaru makin panas aja ya
   Merlin: It's now time to work. Jangan ngerumpi mulu..
   Merlin: Hope you enjoy today.
   Merlin: Komputernya ta dinginin dulu OK
   Merlin: Cape dech, Bye Bye Ahh!

 File Si copia alle seguenti posizioni:
   • %sysdir%\ctfmon.exe.vbe
   • %unit disco%\Thumbs.db.vbe
   • %unit disco%\%file cancellato%.vbe

Viene ricercata la seguente directory:
   • %unit disco%\

Occorre fare attenzione ai seguenti tipi di file:
   • .doc
   • .docx
   • .xls
   • .ppt
   • .jpg
   • .bmp
   • .3gp
   • .rm

In seguito viene eliminato il file originale.



Viene creato il seguente file:

%unit disco%\autorun.inf Questo un file di testo non maligno con il seguente contenuto:
   • [autorun]
     shellexecute=wscript.exe Thumbs.db.vbe




Prova ad eseguire il seguente file:

Nome del file:
   • %sysdir%\cmd.exe
utilizzando i seguenti parametri: shutdown -s -t 00 -f -m

 Registro Viene aggiunta nel registro la seguente chiave con lo scopo di eseguire il processo dopo il riavvio:

[HKLM\Software\Microsoft\Windows\CurrentVersion\Run]
   • CTFMon="%sysdir%\ctfmon.exe.vbe"



Vengono aggiunte le seguenti chiavi di registro:

[HKCU\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer\
   Advanced]
   • Hidden=dword:00000002

[HKLM\Software\Microsoft\Windows NT\CurrentVersion\
   Image File Execution Options\cmd.exe]
   • Debugger="notepad.exe"

[HKLM\Software\Microsoft\Windows NT\CurrentVersion\
   Image File Execution Options\install.exe]
   • Debugger="notepad.exe"

[HKLM\Software\Microsoft\Windows NT\CurrentVersion\
   Image File Execution Options\msconfig.exe]
   • Debugger="notepad.exe"

[HKLM\Software\Microsoft\Windows NT\CurrentVersion\
   Image File Execution Options\regedit.exe]
   • Debugger="notepad.exe"

[HKLM\Software\Microsoft\Windows NT\CurrentVersion\
   Image File Execution Options\AVG Free.exe]
   • Debugger="notepad.exe"

[HKLM\Software\Microsoft\Windows NT\CurrentVersion\
   Image File Execution Options\regedt32.exe]
   • Debugger="notepad.exe"

[HKLM\Software\Microsoft\Windows NT\CurrentVersion\
   Image File Execution Options\RegistryEditor.exe]
   • Debugger="notepad.exe"

[HKLM\Software\Microsoft\Windows NT\CurrentVersion\
   Image File Execution Options\setup.exe]
   • Debugger="notepad.exe"

[HKLM\Software\Microsoft\Windows NT\CurrentVersion\
   Image File Execution Options\setup32.exe]
   • Debugger="notepad.exe"

[HKLM\Software\Microsoft\Windows NT\CurrentVersion\
   Image File Execution Options\AVG 7.5.exe]
   • Debugger="notepad.exe"

[HKLM\Software\Microsoft\Windows NT\CurrentVersion\
   Image File Execution Options\rstrui.exe]
   • Debugger="notepad.exe"

[HKLM\Software\Microsoft\Windows NT\CurrentVersion\
   Image File Execution Options\PCMAV.exe]
   • Debugger="notepad.exe"

[HKLM\Software\Microsoft\Windows NT\CurrentVersion\
   Image File Execution Options\PCMAV-CLN.exe]
   • Debugger="notepad.exe"

[HKLM\Software\Microsoft\Windows NT\CurrentVersion\
   Image File Execution Options\PCMAV-RTP.exe]
   • Debugger="notepad.exe"

[HKLM\Software\Microsoft\Windows NT\CurrentVersion\
   Image File Execution Options\ANSAV.exe]
   • Debugger="notepad.exe"

[HKLM\Software\Microsoft\Windows NT\CurrentVersion\
   Image File Execution Options\AVG.exe]
   • Debugger="notepad.exe"

[HKLM\Software\Microsoft\Windows NT\CurrentVersion\
   Image File Execution Options\run.exe]
   • Debugger="notepad.exe"

[HKLM\Software\Microsoft\Windows NT\CurrentVersion\
   Image File Execution Options\avgw.exe]
   • Debugger="notepad.exe"

[HKLM\Software\Microsoft\Windows NT\CurrentVersion\
   Image File Execution Options\AVG Free Edition.exe]
   • Debugger="notepad.exe"

[HKLM\Software\Microsoft\Windows NT\CurrentVersion\
   Image File Execution Options\AVG Free Edition Test Centre.exe]
   • Debugger="notepad.exe"

[HKLM\Software\Microsoft\Windows NT\CurrentVersion\
   Image File Execution Options\Avg Free Control Center.exe]
   • Debugger="notepad.exe"

[HKLM\Software\Microsoft\Windows NT\CurrentVersion\
   Image File Execution Options\vbren.exe]
   • Debugger="notepad.exe"

[HKLM\Software\Microsoft\Windows NT\CurrentVersion\
   Image File Execution Options\Kaspersky.exe]
   • Debugger="notepad.exe"

[HKLM\Software\Microsoft\Windows NT\CurrentVersion\
   Image File Execution Options\Kaspersky 6.0.2.exe]
   • Debugger="notepad.exe"

[HKLM\Software\Microsoft\Windows NT\CurrentVersion\
   Image File Execution Options\PC Tools.exe]
   • Debugger="notepad.exe"

[HKLM\Software\Microsoft\Windows NT\CurrentVersion\
   Image File Execution Options\AVAST.exe]
   • Debugger="notepad.exe"

[HKLM\Software\Microsoft\Windows NT\CurrentVersion\
   Image File Execution Options\CAV.exe]
   • Debugger="notepad.exe"

[HKLM\Software\Microsoft\Windows NT\CurrentVersion\
   Image File Execution Options\McAfee.exe]
   • Debugger="notepad.exe"

[HKLM\Software\Microsoft\Windows NT\CurrentVersion\
   Image File Execution Options\McAfee VirusScan.exe]
   • Debugger="notepad.exe"

[HKLM\Software\Microsoft\Windows NT\CurrentVersion\
   Image File Execution Options\Symantec.exe]
   • Debugger="notepad.exe"

[HKLM\Software\Microsoft\Windows NT\CurrentVersion\
   Image File Execution Options\Norman.exe]
   • Debugger="notepad.exe"

[HKLM\Software\Microsoft\Windows NT\CurrentVersion\
   Image File Execution Options\TuneUp Utilities.exe]
   • Debugger="notepad.exe"

[HKLM\Software\Microsoft\Windows NT\CurrentVersion\
   Image File Execution Options\TuneUp Utilities 2006.exe]
   • Debugger="notepad.exe"

[HKLM\Software\Microsoft\Windows NT\CurrentVersion\
   Image File Execution Options\TuneUp Utilities 2007.exe]
   • Debugger="notepad.exe"

[HKLM\Software\Microsoft\Windows NT\CurrentVersion\
   Image File Execution Options\Stars TuneUp Utilities.exe]
   • Debugger="notepad.exe"

[HKLM\Software\Microsoft\Windows NT\CurrentVersion\
   Image File Execution Options\Fix the BRONTOK.exe]
   • Debugger="notepad.exe"

[HKLM\Software\Microsoft\Windows NT\CurrentVersion\
   Image File Execution Options\NOD32.exe]
   • Debugger="notepad.exe"

[HKLM\Software\Microsoft\Windows NT\CurrentVersion\
   Image File Execution Options\HijackThis.exe]
   • Debugger="notepad.exe"

[HKLM\Software\Microsoft\Windows NT\CurrentVersion\
   Image File Execution Options\hijack.exe]
   • Debugger="notepad.exe"

[HKLM\Software\Microsoft\Windows NT\CurrentVersion\
   Image File Execution Options\navw32.exe]
   • Debugger="notepad.exe"

[HKLM\Software\Microsoft\Windows NT\CurrentVersion\
   Image File Execution Options\griso.exe]
   • Debugger="notepad.exe"

[HKLM\Software\Microsoft\Windows NT\CurrentVersion\
   Image File Execution Options\procexp.exe]
   • Debugger="notepad.exe"

[HKLM\Software\Microsoft\Windows NT\CurrentVersion\
   Image File Execution Options\avp.exe]
   • Debugger="notepad.exe"

[HKLM\Software\Microsoft\Windows NT\CurrentVersion\
   Image File Execution Options\samdAV 3.3.exe]
   • Debugger="notepad.exe"

[HKLM\Software\Microsoft\Windows NT\CurrentVersion\
   Image File Execution Options\samdAV 3.2.exe]
   • Debugger="notepad.exe"

[HKLM\Software\Microsoft\Windows NT\CurrentVersion\
   Image File Execution Options\smadAV.exe]
   • Debugger="notepad.exe"

[HKLM\Software\Microsoft\Windows NT\CurrentVersion\
   Image File Execution Options\
   Avira Antivir PersonalEdition Classic.exe]
   • Debugger="notepad.exe"

[HKLM\Software\Microsoft\Windows NT\CurrentVersion\
   Image File Execution Options\avcenter.exe]
   • Debugger="notepad.exe"

[HKLM\Software\Microsoft\Windows NT\CurrentVersion\
   Image File Execution Options\AntiVir.exe]
   • Debugger="notepad.exe"

[HKLM\Software\Microsoft\Windows NT\CurrentVersion\
   Image File Execution Options\Avira.exe]
   • Debugger="notepad.exe"

[HKLM\Software\Microsoft\Windows NT\CurrentVersion\
   Image File Execution Options\procmon.exe]
   • Debugger="notepad.exe"

[HKLM\Software\Microsoft\Windows NT\CurrentVersion\
   Image File Execution Options\filemon.exe]
   • Debugger="notepad.exe"

[HKLM\Software\Microsoft\Windows NT\CurrentVersion\
   Image File Execution Options\DiskCleaner.exe]
   • Debugger="notepad.exe"

[HKLM\Software\Microsoft\Windows NT\CurrentVersion\
   Image File Execution Options\RegistryCleaner.exe]
   • Debugger="notepad.exe"

[HKLM\Software\Microsoft\Windows NT\CurrentVersion\
   Image File Execution Options\StarUpManager.exe]
   • Debugger="notepad.exe"

[HKLM\Software\Microsoft\Windows NT\CurrentVersion\
   Image File Execution Options\TuneUp RescueCenter.exe]
   • Debugger="notepad.exe"

[HKLM\Software\Microsoft\Windows NT\CurrentVersion\
   Image File Execution Options\RescueCenter.exe]
   • Debugger="notepad.exe"

[HKLM\Software\Microsoft\Windows NT\CurrentVersion\
   Image File Execution Options\TuneUp RegistryEditor.exe]
   • Debugger="notepad.exe"

[HKLM\Software\Microsoft\Windows NT\CurrentVersion\
   Image File Execution Options\avgcc.exe]
   • Debugger="notepad.exe"

[HKLM\Software\Microsoft\Windows NT\CurrentVersion\
   Image File Execution Options\VPTray.exe]
   • Debugger="notepad.exe"

[HKLM\Software\Microsoft\Windows NT\CurrentVersion\
   Image File Execution Options\VPDN_LU.exe]
   • Debugger="notepad.exe"

[HKLM\Software\Microsoft\Windows NT\CurrentVersion\
   Image File Execution Options\VPC32.exe]
   • Debugger="notepad.exe"

[HKLM\Software\Microsoft\Windows NT\CurrentVersion\
   Image File Execution Options\TweakUI for Windows XP.exe]
   • Debugger="notepad.exe"

[HKLM\Software\Microsoft\Windows NT\CurrentVersion\
   Image File Execution Options\TweakUI.exe]
   • Debugger="notepad.exe"

[HKLM\Software\Microsoft\Windows NT\CurrentVersion\
   Image File Execution Options\MSConfig CleanUp.exe]
   • Debugger="notepad.exe"

[HKLM\Software\Microsoft\Windows NT\CurrentVersion\
   Image File Execution Options\CCleaner.exe]
   • Debugger="notepad.exe"

[HKLM\Software\Microsoft\Windows NT\CurrentVersion\
   Image File Execution Options\Itegrator.exe]
   • Debugger="notepad.exe"



Vengono cambiate le seguenti chiavi di registro:

[HKCU\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer]
   Nuovo valore:
   • NoDriveTypeAutoRun=dword:00000000
   • NoFind=dword:00000001
   • NoFolderOptions=dword:00000001
   • NoRun=dword:00000001
   • NoViewContextMenu=dword:00000001

[HKCR\VBEFile\DefaultIcon]
   Nuovo valore:
   • (Default)=shell32.dll,-50

[HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced]
   Valore precedente:
   • Hidden= %impostazioni definite dell'utente%
     HideFileExt= %impostazioni definite dell'utente%
     SuperHidden= %impostazioni definite dell'utente%
   Nuovo valore:
   • Hidden=dword:00000000
     HideFileExt=dword:00000001
     SuperHidden=dword:00000000

[HKCU\Software\Microsoft\Windows\CurrentVersion\Policies\System]
   Valore precedente:
   • DisableRegistryTools= %impostazioni definite dell'utente%
     DisableTaskMgr= %impostazioni definite dell'utente%
   Nuovo valore:
   • DisableRegistryTools=dword:00000001
     DisableTaskMgr=dword:00000001

 Dettagli del file Linguaggio di programmazione:
Il malware stato scritto in Visual Basic.


Software di compressione:
Per complicarne l'individuazione e ridurre la dimensione del file, viene compresso con un software di compressione.

Descrizione inserita da Monica Ghitun su venerdì 9 novembre 2007
Descrizione aggiornata da Monica Ghitun su venerdì 9 novembre 2007

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