Virus: VBS/Small.Sasan.A Date discovered: 08/11/2007 Type: Worm In the wild: No Reported Infections: Low Distribution Potential: Low to medium Damage Potential: Low to medium Static file: Yes File size: 10.164 Bytes MD5 checksum: efe528483fd3c6ed75a8c1e016026e10 VDF version: 7.00.00.185 IVDF version: 7.00.00.192 - Thursday, November 8, 2007
General Method of propagation: • Mapped network drives Aliases: • Sophos: VBS/Sasan-Fam • Grisoft: VBS/LoveLetter Platforms / OS: • Windows 95 • Windows 98 • Windows 98 SE • Windows NT • Windows ME • Windows 2000 • Windows XP • Windows 2003 Side effects: • Disable security applications • Drops a file • Registry modification Right after execution it runs a windows application which will display the following window: 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! Files It copies itself to the following locations: • %sysdir%\ctfmon.exe.vbe • %drive% \Thumbs.db.vbe • %drive% \%deleted file% .vbe The following directory is searched: • %drive% \ The following file types is payed attention to: • .doc • .docx • .xls • .ppt • .jpg • .bmp • .3gp • .rm The original file is erased afterwards. The following file is created: – %drive% \autorun.inf This is a non malicious text file with the following content: • [autorun] shellexecute=wscript.exe Thumbs.db.vbe It tries to executes the following file: – Filename: • %sysdir%\cmd.exe using the following command line arguments: shutdown -s -t 00 -f -m Registry The following registry key is added in order to run the process after reboot: – [HKLM\Software\Microsoft\Windows\CurrentVersion\Run] • CTFMon="%sysdir%\ctfmon.exe.vbe" The following registry keys are added: – [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" The following registry keys are changed: – [HKCU\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer] New value: • NoDriveTypeAutoRun=dword:00000000 • NoFind=dword:00000001 • NoFolderOptions=dword:00000001 • NoRun=dword:00000001 • NoViewContextMenu=dword:00000001 – [HKCR\VBEFile\DefaultIcon] New value: • (Default)=shell32.dll,-50 – [HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced] Old value: • Hidden= %user defined settings% HideFileExt= %user defined settings% SuperHidden= %user defined settings% New value: • Hidden=dword:00000000 HideFileExt=dword:00000001 SuperHidden=dword:00000000 – [HKCU\Software\Microsoft\Windows\CurrentVersion\Policies\System] Old value: • DisableRegistryTools= %user defined settings% DisableTaskMgr= %user defined settings% New value: • DisableRegistryTools=dword:00000001 DisableTaskMgr=dword:00000001 File details Programming language: The malware program was written in Visual Basic. Runtime packer: In order to aggravate detection and reduce size of the file it is packed with a runtime packer.
Description inserted by Monica Ghitun on Friday, November 9, 2007 Description updated by Monica Ghitun on Friday, November 9, 2007
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