Alert level

Win32/Banker


Encyclopedia entry
Updated: Mar 25, 2009  |  Published: Jul 20, 2006

Aliases
Not available

Alert Level (?)
High

Antimalware protection details
Microsoft recommends that you download the latest definitions to get protected.


Summary

Win32/Banker is a family of data-stealing Trojans. When Win32/Banker is installed on a computer, it can capture banking credentials such as account numbers and passwords from the user. The Trojan can then send the captured information to the attacker by various means. Many variants of Win32/Banker may appear as greeting card software. Most Win32/Banker variants target customers of Brazilian banks.


Symptoms

Many Win32/Banker variants may appear as greeting card software with a filename that contains the string "cartao" (which is Portugese for the English word "card") and may have file extension .exe., .pif, or .scr.


Technical Information (Analysis)

Win32/Banker is a family of data-stealing Trojans that captures banking credentials such as account numbers and passwords from computer users. It then relays the captured information to the attacker. Most Win32/Banker variants target customers of Brazilian banks; some variants target customers of other banks.
 
Many Win32/Banker variants monitor open Web-browser windows for bank names in the title bar or bank URLs in the address bar. Many variants log keystrokes to record credentials that a user enters at banking Web sites. To assist in capturing banking credentials, Win32/Banker may also replace or supplement legitimate bank Web pages with illegitimate Web pages.
 
Win32/Banker variants use various means of sending captured banking credentials to the attacker, including sending an e-mail to the attacker, uploading credentials to an attacker's FTP site, and posting credentials to an attacker's HTTP site.
 
Many variants of Win32/Banker copy themselves to various folders on the infected computer, such as <Windows folder> and <system folder>, and also drop other files there. The Trojan executable file may contain the string "cartao" (which is Portugese for the English word "card") and may have file extension .exe., .pif, or .scr. Win32/Banker may also configure itself to run automatically each time Windows starts, for example by creating entries in registry keys such as HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run. Some variants may also try to disable security-related software such as antivirus and firewall software.


Prevention

Take the following steps to help prevent infection on your system:
  • Enable a firewall on your computer.
  • Get the latest computer updates for all your installed software.
  • Use up-to-date antivirus software.
  • Use caution when opening attachments and accepting file transfers.
  • Use caution when clicking on links to web pages.
  • Avoid downloading pirated software.
  • Protect yourself against social engineering attacks.
  • Use strong passwords.
Enable a firewall on your computer
Use a third-party firewall product or turn on the Microsoft Windows Internet Connection Firewall.
To turn on the Windows Firewall in Windows Vista
  1. Click Start, and click Control Panel.
  2. Click Security.
  3. Click Turn Windows Firewall on or off.
  4. Select On.
  5. Click OK.
To turn on the Internet Connection Firewall in Windows XP
  1. Click Start, and click Control Panel.
  2. Click Network and Internet Connections. If you do not see Network and Internet Connections, click Switch to Category View.
  3. Click Change Windows Firewall Settings.
  4. Select On.
  5. Click OK.
Get the latest computer updates
Updates help protect your computer from viruses, worms, and other threats as they are discovered. It is important to install updates for all the software that is installed in your computer. These are usually available from vendor websites.
 
You can use the Automatic Updates feature in Windows to automatically download future Microsoft security updates while your computer is on and connected to the Internet.
To turn on Automatic Updates in Windows Vista
  1. Click Start, and click Control Panel
  2. Click System and Maintainance.
  3. Click Windows Updates.
  4. Select a setting. Microsoft recommends selecting Install updates automatically and choose a time that is convenient for you. If you do not choose Automatic, but you choose to be notified when updates are ready, a notification balloon appears when new downloads are available to install. Click the notification balloon to review and install the updates.
To turn on Automatic Updates in Windows XP
  1. Click Start, and click Control Panel
  2. Click System.
  3. Click Automatic Updates.
  4. Select a setting. Microsoft recommends selecting Automatic. If you do not choose Automatic, but you choose to be notified when updates are ready, a notification balloon appears when new downloads are available to install. Click the notification balloon to review and install the updates.
Use up-to-date antivirus software
Most antivirus software can detect and prevent infection by known malicious software. To help protect you from infection, you should always run antivirus software that is updated with the latest signature files. Antivirus software is available from several sources. For more information, see http://www.microsoft.com/protect/computer/viruses/vista.mspx.
Use caution when opening attachments and accepting file transfers
Exercise caution with e-mail and attachments received from unknown sources, or received unexpectedly from known sources.  Use extreme caution when accepting file transfers from known or unknown sources.
Use caution when clicking on links to Web pages
Exercise caution with links to web pages that you receive from unknown sources, especially if the links are to a Web page that you are not familiar with, unsure of the destination of, or suspicious of. Malicious software may be installed in your system simply by visiting a Web page with harmful content.
Avoid downloading pirated software
Threats may also be bundled with software and files that are available for download on various torrent sites. Downloading "cracked" or "pirated" software from these sites carries not only the risk of being infected with malware, but is also illegal. For more information, see 'The risks of obtaining and using pirated software'.
Protect yourself from social engineering attacks
While attackers may attempt to exploit vulnerabilities in hardware or software in order to compromise a system, they also attempt to exploit vulnerabilities in human behavior in order to do the same. When an attacker attempts to take advantage of human behavior in order to persuade the affected user to perform an action of the attacker's choice, it is known as 'social engineering'. Essentially, social engineering is an attack against the human interface of the targeted system. For more information, see 'What is social engineering?'.
Use Strong Passwords
Attackers may try to gain access to your Windows account by guessing your password. It is therefore important that you use a strong password – one that cannot be easily guessed by an attacker. A strong password is one that has at least 8 characters, and combines letters, numbers, and symbols. For more information, see http://www.microsoft.com/protect/yourself/password/create.mspx.


Recovery

Manual removal is not recommended for this threat. To detect and remove this threat and other malicious software that may have been installed, run a full-system scan with an up-to-date antivirus product such as the Microsoft online scanner (http://safety.live.com). For more information, see http://www.microsoft.com/protect/computer/viruses/vista.mspx.