Prevention against attacks

Prevention against attacks needs continuous maintenance and monitoring of systems. Vulnerabilities in systems and software are detected almost daily. Numerous viruses, Trojans and worms appear every week. For the preparation and prevention against attacks, it is of primary importance to follow up the overview regarding the attacks used in Internet and react to the changing threats and security requirements. In the following, a model for intensified protection against attacks is presented:

• Analyse the risks related to information security.
• Document the structure and addresses of your local area network.
• Update your operating system and application software to remove all known threats to information security.
• Close all services which are not necessarily needed, such as ftp, telnet and smtp services, in your system. Restrict access to the necessary services to those entitled to use them.
• Use the network controls to restrict access of external communications to your network. Allow only necessary traffic from your own network to external networks. Restrict also the traffic between your own networks by routing and firewall systems.
• Use proxy servers in communication from the internal network to the public network services.
• Use strong user verification in your systems, for instance single-time passwords, smart cards or biometric identification systems.
• Protect your network traffic by encryption. Use encrypting protocols in terminal connections and data transmission.
• Use network monitoring tools to detect attacks or attempts of such and vulnerabilities in your system.
• Protect the log data of the systems in such a way that their processing and destruction is impossible. If necessary, use a centralised log server.
• Avoid systems which are bypassing the firewall of your network, such as modem pools with weak verification.
• Create remote connections to your systems only by using strongly encrypted connections and reliable verification mechanisms.
• Test your systems regularly by software tools to detect possible security flaws. In addition, do it always after having updated the software and services in your system.
• Use antivirus software.
• Train the users of your information system to take notice of the secure working methods. Ask them to report all suspicious incidents.
• Take care of the physical security of your systems by means of access control systems and structural arrangements.