Win32/Harnig

• Enable a firewall on your computer.
• Get the latest computer updates for all your installed software.
• Use up-to-date antivirus software.
• Limit user privileges on the computer.
• 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.

Use a third-party firewall product or turn on the Microsoft Windows Internet Connection Firewall.

• How to turn on the Windows Firewall in Windows 7
• How to turn on the Windows Firewall in Windows Vista
• How to turn on the Windows firewall in Windows XP

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.

• How to turn on Automatic Updates in Windows 7
• How to turn on Automatic Updates in Windows Vista
• How to turn on Automatic Updates in Windows XP

Most antivirus software can detect and prevent infection by known malicious software. To help protect you from infection, you should always run antivirus software, such as Microsoft Security Essentials, that is updated with the latest signature files. For more information, see http://www.microsoft.com/security/antivirus/av.aspx.

Starting with Windows Vista and Windows 7, Microsoft introduced User Account Control (UAC), which, when enabled, allowed users to run with least user privileges. This scenario limits the possibility of attacks by malware and other threats that require administrative privileges to run.

 

You can configure UAC in your computer to meet your preferences:

• User Account Control in Windows 7
• User Account Control in Windows Vista
• Applying the Principle of Least Privilege in Windows XP
• More on User Account Control

Exercise caution with email and attachments received from unknown sources, or received unexpectedly from known sources.  Use extreme caution when accepting file transfers from known or unknown sources.

Exercise caution with links to web pages that you receive from unknown sources, especially if the links are to a webpage that you are not familiar with, unsure of the destination of, or suspicious of. Malicious software may be installed in your computer simply by visiting a webpage with harmful content.

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'.

While attackers may attempt to exploit vulnerabilities in hardware or software to compromise a computer, they also attempt to exploit vulnerabilities in human behavior to do the same. When an attacker attempts to take advantage of human behavior 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 computer. For more information, see 'What is social engineering?'.

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 eight characters, and combines letters, numbers, and symbols. For more information, see http://www.microsoft.com/protect/yourself/password/create.mspx.