Need help? Ask the community or hire an expert.
Go to Avira Answers
Virus:Worm/Brontok.V
Date discovered:21/09/2006
Type:Worm
In the wild:Yes
Reported Infections:Low to medium
Distribution Potential:Low
Damage Potential:Low to medium
Static file:Yes
File size:42.734 Bytes
MD5 checksum:58073efd92e92c1f1155acc3282595c0
IVDF version:6.36.00.44 - Thursday, September 21, 2006

 General Aliases:
   •  Sophos: W32/Brontok-E
   •  Bitdefender: Win32.Generic.5471
   •  Panda: W32/Brontok.GS.worm


Platforms / OS:
   • Windows 2000
   • Windows XP
   • Windows 2003


Side effects:
   • Lowers security settings
   • Downloads malicious files
   • Drops malicious files
   • Registry modification

 Files It copies itself to the following locations:
   • %SYSDIR%\%current username%'s Setting.scr
   • %HOME%\Start Menu\Programs\Startup\Empty.pif
   • %HOME%\Local Settings\Application Data\winlogon.exe
   • %HOME%\Local Settings\Application Data\smss.exe
   • %HOME%\Local Settings\Application Data\lsass.exe
   • %WINDIR%\ShellNew\sempalong.exe
   • %HOME%\Local Settings\Application Data\csrss.exe
   • %WINDIR%\eksplorasi.exe
   • %HOME%\Local Settings\Application Data\services.exe
   • %SYSDIR%\drivers\etc\hosts-Denied By-%current username%.com
   • %HOME%\Local Settings\Application Data\inetinfo.exe
   • %HOME%\Templates\Brengkolang.com
   • %all shared folders%\Data %current username%.exe
   • %all shared folders%\%folder name%.exe



It overwrites a file.
– C:\autoexec.bat



It deletes the following files:
   • %HOME%\Local Settings\Application Data\BronNPath0.txt
   • %HOME%\Local Settings\Application Data\BronNetDomList.bat
   • %HOME%\Local Settings\Application Data\BronFoldNetDomList.txt



The following files are created:

– %HOME%\Local Settings\Application Data\BronNPath0.txt
– %HOME%\Local Settings\Application Data\Kosong.Bron.Tok.txt
– %HOME%\Local Settings\Application Data\BronFoldNetDomList.txt
– %HOME%\Local Settings\Application Data\BronNPath0.txt
– %HOME%\Local Settings\Application Data\Update.11.Bron.Tok.bin
– %HOME%\Local Settings\Application Data\Bron.tok.A11.em.bin
– %HOME%\Local Settings\Application Data\ListHost11.txt
– %HOME%\Local Settings\Application Data\BronNetDomList.bat Furthermore it gets executed after it was fully created. This batch file is used to delete a file.



It tries to download some files:

– The location is the following:
   • http://www.geocities.com/sbllma5/**********


– The location is the following:
   • http://www.geocities.com/sbllma5/**********




It tries to execute the following files:

– Filename:
   • %HOME%\Local Settings\Application Data\inetinfo.exe


– Filename:
   • %HOME%\Local Settings\Application Data\csrss.exe


– Filename:
   • %HOME%\Local Settings\Application Data\smss.exe


– Filename:
   • %HOME%\Local Settings\Application Data\winlogon.exe


– Filename:
   • at /delete /y


– Filename:
   • at 17:08 /every:M,T,W,Th,F,S,Su "%HOME%\Templates\Brengkolang.com"


– Filename:
   • %HOME%\Local Settings\Application Data\services.exe


– Filename:
   • %HOME%\Local Settings\Application Data\lsass.exe


– Filename:
   • cmd /c "%HOME%\Local Settings\Application Data\BronNetDomList.bat"


– Filename:
   • ping kaskus.com -n 250 -l 747

 Registry The following registry keys are added in order to run the processes after reboot:

– [HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run]
   • "Bron-Spizaetus"=""%WINDIR%\ShellNew\sempalong.exe""



The following registry keys are added:

– [HKCU\software\microsoft\windows\currentversion\Policies\System]
   • "DisableCMD"=dword:0x00000000
   • "DisableRegistryTools"=dword:0x00000001

– [HKLM\SOFTWARE\Classes\TypeLib\
   {97d25db0-0363-11cf-abc4-02608c9e7553}\1.0\FLAGS]
   • "@"="0"

– [HKLM\SOFTWARE\Classes\TypeLib\
   {97d25db0-0363-11cf-abc4-02608c9e7553}\1.0\HELPDIR]
   • "@"="%SYSDIR%"

– [HKCU\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer]
   • "NoFolderOptions"=dword:0x00000001



The following registry keys are changed:

– [HKLM\SOFTWARE\Classes\TypeLib\
   {97d25db0-0363-11cf-abc4-02608c9e7553}\1.0\0\win32]
   New value:
   • "@"="%SYSDIR%\activeds.tlb"

– [HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon]
   New value:
   • "Shell"="Explorer.exe "%WINDIR%\eksplorasi.exe""

– [HKLM\SOFTWARE\Classes\TypeLib\
   {97d25db0-0363-11cf-abc4-02608c9e7553}\1.0]
   New value:
   • "@"="Active DS Type Library"

– [HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced]
   New value:
   • "Hidden"=dword:0x00000000
   • "HideFileExt"=dword:0x00000001
   • "ShowSuperHidden"=dword:0x00000000

– [HKCU\Software\Microsoft\Internet Explorer\Toolbar]
   New value:
   • "Locked"=dword:0x00000001

 File details Runtime packer:
In order to aggravate detection and reduce size of the file it is packed with a runtime packer.

Description inserted by Petre Galan on Thursday, November 4, 2010
Description updated by Petre Galan on Thursday, November 11, 2010

Back . . . .