Infostealer.Tarno.T

The threat is reported to arrive on the compromised computer as an attachment to an email message with the following characteristics:

From:
payments-support@amazon.co.uk

Subject:
Your payment done.

Body:
Dear customer,
We're writing to let you know that we've initiated a transfer from your bank account (Last 4-digits: 0402) for the following amount:GBP 313.14
(ORDER 0220873 DATE 20.03.2006) Funds should leave account in approximately three to five working days. See your statement details in attachment. To review your account at any time please access your Account Summary: [https://]payments.amazon.co.uk/exec/login 
If you have any questions or concerns regarding this settlement please contact us at payments-support@amazon.co.ukAmazon.co.uk Marketplace

-- Amazon Services Europe S.a.r.l.Sell Your Stuff [http://]www.amazon.co.uk


When Infostealer.Tarno.T is executed, it performs the following actions:

1. Adds the value:
   
   "[PATH TO THE TROJAN]" = "[PATH TO THE TROJAN]:*:enabled:B"
   
   to the following registry entry:
   
   HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\ServiceS\Sharedaccess\parameters\Firewallpolicy\StandardProfile\AuthorizedApplications\List
   
   in order to bypass the Windows Firewall by adding itself to the authorized list.
   
   
2. Downloads a file named suhoy112.exe from the following location:
   
   [http://]akgula[REMOVED]
   
   
3. Creates the following files:
   
   
   • %System%\guisetup.exe
   • %System%\msupdate.dll
     
     Note: %System% is a variable that refers to the System folder. By default this is C:\Windows\System (Windows 95/98/Me), C:\Winnt\System32 (Windows NT/2000), or C:\Windows\System32 (Windows XP).
     
     
4. Adds the following registry subkeys:
   
   HKEY_CLASSES_ROOT\CLSID\{3A4E6FF3-BF59-446E-9DC8-731BCE2F349A}
   HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Browser Helper Objects\{3A4E6FF3-BF59-446E-9DC8-731BCE2F349A}
   
   which registers the file %System%\msupdate.dll as a browser helper object so that it runs every time Internet Explorer starts.
   
   
5. Adds the following registry subkey:
   
   HKEY_CLASSES_ROOT\msupdate.Microsoft Update Service
   
   
6. Monitors windows and Web pages that contain the following strings, in an attempt to gather user name and password data related to Internet banking activities:
   
   
   • gold
   • cash
   • bank
   • pas
   • log
   • user
   • usr
   • pwd
   • psw
   • parol
   • firma
   • pin
   • clave
   • trans
   • porcue
   • memorable
   • secret
     
     
7. Monitors Web pages with the following URLs, some of which are also related to Internet banking activities:
   
   
   • [https://]olb2.nationet.com/MyAccounts
   • [https://]yahoo.com
   • [https://]ibank.barclays.co.uk/onlb/q/LoginPasscode
   • [https://]olb2.nationet.com/MyAccounts/
   • [https://]ibank.barclays.co.uk/olb/q/LoginPasscode
   • [https://]welcome6.co-operativebank.co.uk/CBIBSWeb/loginSpi.do
   • barclays.com
   • hsbc.com
   • olb2.nationet.co.uk
   • deutsche-bank.de
   • www.com
   • co-operativebank.com
   • e-gold.com
   • smile.com
   • www.com
   • barclays.co.uk
   • hsbc.co.uk
   • olb2.nationet.com
   • nwolb.com
   • co-operativebank.co.uk
   • my.if.com
   • smile.co.uk
   • cahoot.com
   • webbank.openplan.co.uk
   • http://mail.yahoo.com
   • anbusiness.com
     
     
8. Captures keystrokes entered into any windows that it finds. It also logs HTML Web forms transferred from the compromised computer to any remote Web sites visited, once an active window exists.
   
   
9. Logs the information it gathers into some of the following files:
   
   
   • %System%\wint.ini
   • %System%\ierror.rep
   • %System%\sui.dll
   • %System%\sei.dll
   • %System%\wineror.dat
     
     
10. Creates the following file:
    
    %System%\winte.html
    
    
11. Creates the following folders which may be used to store configuration files or extensions for this Trojan:
    
    
    • %System%\suskn
    • %System%\sucontr
    • %System%\suact
      
      
12. Creates the following folder:
    
    %SystemDrive%\cardon
    
    Note: %SystemDrive% is a variable that refers to the drive on which Windows is installed. By default, this is drive C.
    
    
13. Sends stolen information to URLs under the following web address:
    
    [http://]oxygunn.com/[REMOVED]

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.

Summary