Infostealer.Tarno.C

1. Creates the following files:
   • %System%\Systems.exe
   • %System%\Systemdll.dll: This file contains functions to log keystrokes.
     
     

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     Note: %System% is a variable. The Trojan locates the System folder and drops the files itself to that location. By default, this is C:\Windows\System (Windows 95/98/Me), C:\Winnt\System32 (Windows NT/2000), or C:\Windows\System32 (Windows XP).
     

     ---

     
     
2. Adds the value:
   
   "NAV Agent"="%System%\systems.exe"
   "Kernell" = "%System%\systems.exe"
   
   to the registry key:
   
   HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run
   
   so that the Trojan is executed on startup.
   
   
3. Installs hook procedures into a hook chain to monitor the system for any keyboard messages. The keyboard hook procedures process the messages and pass the hook information to the next hook procedure in the current hook chain. This permits Infostealer.Tarno.C to intercept key strokes.
   
   
4. Waits for windows that have certain strings in the title bar, or that contain certain URLs. When it finds one, it activates. Typically, such windows would be Web browser windows displaying login screens for financial services. The URLs, followed by their respective title strings, are:
   • "http:/ /www.beg.com.br/","BEG"
   • "https:/ /ib.beg.com.br/cgi_programs/ibhtml.exe","BEG Net Banking"
   • "http:/ /www.banrisul.com.br/","B A N R I S U L"
   • "http:/ /www.banrisul.com.br/","http:/ /www.banrisul.com.br/"
   • "http:/ /www.banestado.com.br/","Banco Banestado S. A. - Banco Mltiplo"
   • "https:/ /bank1.banestado.com.br/","InternetBank Banestado"
   • "www2.bancobrasil.com.br"
   • "http:/ /www.bb.com.br/appbb/portal/index.jsp"
   • "https:/ /internetcaixa.caixa.gov.br/NASApp/SIIBC/index_verif.processa"
   • "https:/ /internetcaixa.caixa.gov.br/"
   • "http:/ /www.cef.gov.br/","http:/ /www.cef.gov.br/"
   • "http:/ /www.itau.com.br/indexIE.htm","http:/ /www.itau.com.br/indexIE.htm"
   • "http:/ /www.itau.com.br/indexIE.htm","Banco Ita - Feito Para Voc
   • "http:/ /www.banespa.com.br/","Banespa"
   • "http:/ /www.banespa.com.br/","http:/ /www.banespa.com.br/"
   • "http:/ /www.santander.com.br/port/index.asp","Banco Santander"
   • "http:/ /www.hsbc.com.br/","http:/ /www.hsbc.com.br/"
   • "http:/ /www.hsbc.com.br","HSBC Bank Brasil S.A. - Banco Mltiplo"
   • "http:/ /www.hsbc.com.br/","HSBC Bank Brasil S.A. - Banco Mltiplo"
   • "https:/ /home.citidirect-br.citibank.com/citidirect/servlet/SvCtIndex","Citibank Online"
   • "http:/ /www.bancoreal.com.br/","Banco ABN AMRO REAL - Portal Brasil"
   • "http:/ /www.bancoreal.com.br/"," Banco ABN AMRO REAL - Portal Brasil"
   • "https:/ /www.realsecureweb.com.br/scripts/engine_brpi.dll?OPERA=GetFilteredPage&PAGE=index_ib3","Real Internet Banking
   • "https:/ /www2.realsecureweb.com.br/scripts/engine_brpi.dll?OPERA=GetFilteredPage&PAGE=index_ib3","Real Internet Banking
   • "http:/ /www.unibanco.com.br/","Unibanco.com"
   • "https:/ /www.submarino.com.br/payment.asp?newaddr=","Submarino"
   • "https:/ /www.americanas.com.br/cgi-bin/WebObjects/carrinho.woa/wo/14.0.TemplateSeguroAcom.5.11.0","Americanas.com as Lojas Americanas sua"
   • "http:/ /www.safranet.com.br","Banco Safra S.A."
   • "http:/ /www.safranet.com.br/","Banco Safra S.A."
   • "http:/ /www.banerj.com.br/indexIE.htm","Banco Banerj S/A."
   • "http:/ /www.mercantil.com.br/","BMB - Pgina Principal"
   • "http:/ /www.mercantil.com.br","BMB - Pgina Principal"
   • "https:/ /banknet.brb.com.br/wtrxa/default.trx","BRB-Banknet"
   • "http:/ /www.brb.com.br/","BRB - BANCO DE BRAS
   • "http:/ /www.brb.com.br","BRB - BANCO DE BRAS
   • "https:/ /banknet.brb.com.br/brbBanknet/","Banknet"
   • "http:/ /www.bcn.com.br","http:/ /www.bcn.com.br"
   • "http:/ /www.bcn.com.br/","http:/ /www.bcn.com.br/"
   • "http:/ /www.bcn.com.br/","Banco BCN S.A."
   • "http:/ /www.bbvbrasil.com.br/site/home/home.asp","BBV"
   • "http:/ /www.bbvbrasil.com.br/","http:/ /www.bbvbrasil.com.br/"
   • "http:/ /www.banrisul.com.br","http:/ /www.banrisul.com.br"
   • "http:/ /www.bankboston.com.br/","BankBoston"
   • "http:/ /www.bankboston.com.br","BankBoston"
   • "http:/ /www.banestes.com.br/site/index.html","BANESTES S.A | Banco do Estado do Esprito Santo"
   • "http:/ /www.banestes.com.br/site/index.html","http:/ /www.banestes.com.br/site/index.html"
   • "http:/ /www.sudameris.com.br/",":: Banco Sudameris Brasil S.A. ::"
   • "http:/ /www.bancosantos.com.br/","Banco Santos"
   • "http:/ /www.bancosantos.com.br/","http:/ /www.bancosantos.com.br/"
   • "https:/ /www2.rural.com.br/RuralIBank/principal.jsp","Banco Rural"
   • "http:/ /www.alfanet.com.br/","ALFANET"
   • "http:/ /www.alfanet.com.br","ALFANET"
   • "http:/ /www.bradesco.com.br/","http:/ /www.bradesco.com.br/"
   • "http:/ /www.bradesco.com.br","Bradesco - Colocando voc sempre frente"
   • "file:/ //C:/BancoBrasil/officeIE/index.html","index"
   • "file:/ //D:/BancoBrasil/officeIE/index.html","index"
   • "http:/ /www.serasa.com.br/","Serasa S.A"
     
     
5. Sends the stolen information to a predetermined email address, using its own SMTP engine.

Recommendations

Symantec Security Response encourages all users and administrators to adhere to the following basic security "best practices":

• Use a firewall to block all incoming connections from the Internet to services that should not be publicly available. By default, you should deny all incoming connections and only allow services you explicitly want to offer to the outside world.
• Enforce a password policy. Complex passwords make it difficult to crack password files on compromised computers. This helps to prevent or limit damage when a computer is compromised.
• Ensure that programs and users of the computer use the lowest level of privileges necessary to complete a task. When prompted for a root or UAC password, ensure that the program asking for administration-level access is a legitimate application.
• Disable AutoPlay to prevent the automatic launching of executable files on network and removable drives, and disconnect the drives when not required. If write access is not required, enable read-only mode if the option is available.
• Turn off file sharing if not needed. If file sharing is required, use ACLs and password protection to limit access. Disable anonymous access to shared folders. Grant access only to user accounts with strong passwords to folders that must be shared.
• Turn off and remove unnecessary services. By default, many operating systems install auxiliary services that are not critical. These services are avenues of attack. If they are removed, threats have less avenues of attack.
• If a threat exploits one or more network services, disable, or block access to, those services until a patch is applied.
• Always keep your patch levels up-to-date, especially on computers that host public services and are accessible through the firewall, such as HTTP, FTP, mail, and DNS services.
• Configure your email server to block or remove email that contains file attachments that are commonly used to spread threats, such as .vbs, .bat, .exe, .pif and .scr files.
• Isolate compromised computers quickly to prevent threats from spreading further. Perform a forensic analysis and restore the computers using trusted media.
• Train employees not to open attachments unless they are expecting them. Also, do not execute software that is downloaded from the Internet unless it has been scanned for viruses. Simply visiting a compromised Web site can cause infection if certain browser vulnerabilities are not patched.
• If Bluetooth is not required for mobile devices, it should be turned off. If you require its use, ensure that the device's visibility is set to "Hidden" so that it cannot be scanned by other Bluetooth devices. If device pairing must be used, ensure that all devices are set to "Unauthorized", requiring authorization for each connection request. Do not accept applications that are unsigned or sent from unknown sources.
• For further information on the terms used in this document, please refer to the Security Response glossary.