Common points of compromise tend to be systems with poor password security in conjunction with the use of Remote Desktop Applications, such as PCAnywhere or LogMeIn. Hackers are able to remotely manage the systems with relative ease in these cases. Some common malware tools found on compromised systems are: (1) memory dumpers, (2) keystroke loggers, and (3) packet sniffers. This is not an all-inclusive list.

Recommendations

The following is a list of preventative measures against malarkey and other malicious code that are provided courtesy of the Symantec Security Response team:

  • Use a firewall to lock all incoming connections from the Internet to services that should not be publicly available. By default, you should deny all incoming connections and only allows services you explicitly want to offer to the outside world. 
  • Enforce a password policy. Complex passwords make it difficult to crack password files on comprised 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 networks services, disable, or block access to, those services until 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 .src files.
  • Isolate compromised computers quickly to prevent threats from spreading further. Perform a forensic analysis and restore the computer 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 Website 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.

Additionally, if the store offers public Wi-Fi service to customers, it would be wise to have the back-of-house and point-of-sale terminals on separates, secure networks.