Network security

Network security consists of the provisions made in an underlying computer network infrastructure, policies adopted by the network administrator to protect the network and the network-accessible resources from unauthorized access, and consistent and continuous monitoring and measurement of its effectiveness (or lack) combined together.

Comparison with information security

The terms network security and information security are often used interchangeably, however network security is generally taken as providing protection at the boundaries of an organization, keeping the intruders (e.g. black hat hackers, script kiddies, etc.) out. Network security systems today are mostly effective, so the focus has shifted to protecting resources from attack or simple mistakes by people inside the organization, e.g. with Data Loss Prevention (DLP). One response to this insider threat in network security is to compartmentalize large networks, so that an employee would have to cross an internal boundary and be authenticated when they try to access privileged information. Information security is explicitly concerned with all aspects of protecting information resources, including network security and DLP.

Network security concepts

Network security starts from authenticating any user, commonly (one factor authentication) with a username and a password (something you know). With two factor authentication something you have is also used (e.g. a security token or 'dongle', an ATM card, or your mobile phone), or with three factor authentication something you are is also used (e.g. a fingerprint or retinal scan). Once authenticated, a stateful firewall enforces access policies such as what services are allowed to be accessed by the network users. Though effective to prevent unauthorized access, this component fails to check potentially harmful content such as computer worms being transmitted over the network. An intrusion prevention system (IPS) helps detect and inhibit the action of such malware. An anomaly-based intrusion detection system also monitors network traffic for suspicious content, unexpected traffic and other anomalies to protect the network e.g. from denial of service attacks or an employee accessing files at strange times. Communication between two hosts using the network could be encrypted to maintain privacy. Individual events occurring on the network could be tracked for audit purposes and for a later high level analysis.

Honeypots, essentially decoy network-accessible resources, could be deployed in a network as surveillance and early-warning tools. Techniques used by the attackers that attempt to compromise these decoy resources are studied during and after an attack to keep an eye on new exploitation techniques. Such analysis could be used to further tighten security of the actual network being protected by the honeypot.

A useful summary of standard concepts and methods in network security is given by in the form of an extensible ontology of network security attacks.

Security management

Security Management for networks is different for all kinds of situations. A small home or an office would only require basic security while large businesses will require high maintenance and advanced software and hardware to prevent malicious attacks from hacking and spamming.

Small homes

• A basic firewall like COMODO Internet Security or a unified threat management system.
• For Windows users, basic Antivirus software like AVG Antivirus, ESET NOD32 Antivirus,Kaspersky, McAfee, or Norton AntiVirus. An anti-spyware program such as Windows Defender or Spybot would also be a good idea. There are many other types of antivirus or antispyware programs out there to be considered.
• When using a wireless connection, use a robust password. Also try and use the strongest security supported by your wireless devices, such as WPA or WPA2.
• Use passwords for all accounts.
• Have multiple accounts per family member, using non-administrative accounts for day-to-day activities. Disable the guest account (Control Panel> Administrative Tools> Computer Management> Users).
• Raise awareness about information security to children.

Medium businesses

• A fairly strong firewall or Unified Threat Management System
• Strong Antivirus software and Internet Security Software.
• For authentication, use strong passwords and change it on a bi-weekly/monthly basis.
• When using a wireless connection, use a robust password.
• Raise awareness about physical security to employees.
• Use an optional network analyzer or network monitor.
• An enlightened administrator or manager.

Large businesses

• A strong firewall and proxy to keep unwanted people out.
• A strong Antivirus software package and Internet Security Software package.
• For authentication, use strong passwords and change it on a weekly/bi-weekly basis.
• When using a wireless connection, use a robust password.
• Exercise physical security precautions to employees.
• Prepare a network analyzer or network monitor and use it when needed.
• Implement physical security management like closed circuit television for entry areas and restricted zones.
• Security fencing to mark the company's perimeter.
• Fire extinguishers for fire-sensitive areas like server rooms and security rooms.
• Security guards can help to maximize security.

School

• An adjustable firewall and proxy to allow authorized users access from the outside and inside.
• Strong Antivirus software and Internet Security Software packages.
• Wireless connections that lead to firewalls.
• Children's Internet Protection Act compliance.
• Supervision of network to guarantee updates and changes based on popular site usage.
• Constant supervision by teachers, librarians, and administrators to guarantee protection against attacks by both internet and sneakernet sources.

Large Government

• A strong firewall and proxy to keep unwanted people out.
• Strong Antivirus software and Internet Security Software suites.
• Strong encryption.
• Whitelist authorized wireless connection, block all else.
• All network hardware is in secure zones.
• All host should be on a private network that is invisible from the outside.
• Put all servers in a DMZ, or a firewall from the outside and from the inside.
• Security fencing to mark perimeter and set wireless range to this.

Further reading

• Security of the Internet (The Froehlich/Kent Encyclopedia of Telecommunications vol. 15. Marcel Dekker, New York, 1997, pp. 231-255.)
• Introduction to Network Security, Matt Curtin.
• Security Monitoring with Cisco Security MARS, Gary Halleen/Greg Kellogg, Cisco Press, Jul. 6, 2007.
• Self-Defending Networks: The Next Generation of Network Security, Duane DeCapite, Cisco Press, Sep. 8, 2006.
• Security Threat Mitigation and Response: Understanding CS-MARS, Dale Tesch/Greg Abelar, Cisco Press, Sep. 26, 2006.
• Deploying Zone-Based Firewalls, Ivan Pepelnjak, Cisco Press, Oct. 5, 2006.
• Network Security: PRIVATE Communication in a PUBLIC World, Charlie Kaufman | Radia Perlman | Mike Speciner, Prentice-Hall, 2002. ISBN .
• Network Infrastructure Security, Angus Wong and Alan Yeung, Springer, 2009.

See also

• Crimeware
• Data Loss Prevention
• Wireless LAN Security
• Timeline of hacker history
• Information Leak Prevention
• Network Security Toolkit
• TCP sequence prediction attack
• TCP Gender Changer
• Netsentron

External links

• Stonesoft whitepapers about network security, VPN, IPS and security on virtualized environments
• Cisco IT Case Studies about Security and VPN
• Debate: The data or the source - which is the real threat to network security? - Video
• OpenLearn - Network Security