If you see unsolicited pop-ups, such as a message warning that a computer is infected and offering virus removal, don’t follow links or click to accept software downloads. Doing so could result in you downloading malicious software.
Such links can take you to bogus websites, where any confidential information you enter, such as account details and passwords, can be stolen and misused. Always enter the website address you want to visit in the address bar in your browser.
You should use a different password for each site where you have a user account. If a password is compromised, only one account will be affected.
You can disable Java or ActiveX applets, or ask to be warned that such code is running. For example in Microsoft Internet Explorer, select Tools|Internet|Options|Security|Custom Level and select the settings you want.
In a company environment, you may want to prevent users from accessing sites that are inappropriate for workplace use, or that may pose a security threat (for example, by installing spyware on computers), or that may give offence. You can do this with web filtering software or a hardware “appliance”.
Reputation filtering software can check the sender addresses in email against a database that shows how often mail from that address is spam, or contains viruses, worms, etc. The software then assigns the email a “reputation” score that is used to decide whether to block the email or to slow down its delivery (giving priority to email with a better reputation).
A network firewall is installed at your company boundary and admits only authorised types of traffic. A client firewall is installed on each computer on your network, and also allows only authorised traffic, thereby blocking hackers and internet worms. In addition, it prevents the computer from communicating with the internet via unauthorised programs.
You can use a router to limit connection between the internet and specific computers. Many routers also incorporate a network firewall.
