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{{short description|Computer network access control|noreplace}}
'''Network security''' consists of the [[policies|policies, processes]] and practices adopted to prevent, detect and monitor [[unauthorized]] access, [[Abuse|misuse]], modification, or denial of a [[computer network]] and network-accessible resources.<ref>{{Cite web|date=2018-08-09|title=What is Network Security? Poda myre |url=https://www.forcepoint.com/cyber-edu/network-security|access-date=2020-12-05|website=Forcepoint|language=en}}</ref> Network security involves the authorization of access to data in a network, which is controlled by the [[network administrator]]. Users choose or are assigned an ID and password or other authenticating information that allows them access to information and programs within their authority. Network security covers a variety of computer networks, both public and private, that are used in everyday jobs: conducting transactions and communications among businesses, [[Government agency|government agencies]] and individuals. Networks can be private, such as within a company, and others which might be open to public access. Network security is involved in organizations, enterprises, and other types of institutions. It does as its title explains: it secures the network, as well as protecting and overseeing operations being done. The most common and simple way of protecting a network resource is by assigning it a unique name and a corresponding password.

==Network security concept==
Network security starts with [[authentication]], commonly with a username and a [[password]]. Since this requires just one detail authenticating the user name—i.e., the password—this is sometimes termed one-factor authentication. With [[two-factor authentication]], something the user 'has' is also used (e.g., a [[security token]] or '[[dongle]]', an [[ATM card]], or a [[mobile phone]]); and with three-factor authentication, something the user 'is' is also used (e.g., a [[fingerprint]] or [[retinal scan]]).

Once authenticated, a [[Firewall (networking)|firewall]] enforces access policies such as what services are allowed to be accessed by the network users.<ref>A Role-Based Trusted Network Provides [http://newsroom.cisco.com/dlls/2008/ts_010208b.html?sid=BAC-NewsWire Pervasive Security and Compliance] - interview with [[Jayshree Ullal]], senior VP of [[Cisco]]</ref><ref>{{Cite journal |last1=Macfarlane |first1=Richard |last2=Buchanan |first2=William |last3=Ekonomou |first3=Elias |last4=Uthmani |first4=Omair |last5=Fan |first5=Lu |last6=Lo |first6=Owen |date=2012 |title=Formal security policy implementations in network firewalls |url=https://linkinghub.elsevier.com/retrieve/pii/S0167404811001192 |journal=Computers & Security |language=en |volume=31 |issue=2 |pages=253–270 |doi=10.1016/j.cose.2011.10.003}}</ref> Though effective to prevent unauthorized access, this component may fail to check potentially harmful content such as [[computer worm]]s or [[Trojan horse (computing)|Trojan]]s being transmitted over the network. [[Anti-virus software]] or an [[intrusion prevention system]] (IPS)<ref>Dave Dittrich, [http://staff.washington.edu/dittrich/network.html ''Network monitoring/Intrusion Detection Systems (IDS)''] {{webarchive|url=https://web.archive.org/web/20060827234520/http://staff.washington.edu/dittrich/network.html |date=2006-08-27 }}, University of Washington.</ref> help detect and inhibit the action of such [[malware]]. An [[anomaly-based intrusion detection system]] may also monitor the network like wireshark [[Deep packet inspection|traffic]] and may be logged for audit purposes and for later high-level analysis. Newer systems combining unsupervised [[machine learning]] with full network traffic analysis can detect active network attackers from malicious insiders or targeted external attackers that have compromised a user machine or account.<ref>{{cite web|url=http://www.darkreading.com/operations/automating-breach-detection-for-the-way-security-professionals-think/a/d-id/1322443|title=Dark Reading: Automating Breach Detection For The Way Security Professionals Think|date=October 1, 2015}}</ref>

Communication between two hosts using a network may be encrypted to maintain security and privacy.

[[Honeypot (computing)|Honeypots]], essentially [[decoy]] network-accessible resources, may be deployed in a network as [[surveillance]] and early-warning tools, as the honeypots are not normally accessed for legitimate purposes. Honeypots are placed at a point in the network where they appear vulnerable and undefended, but they Network security involves the authorization of access to data in a network, which is controlled by the network administrator. Users choose or are assigned an ID ...are actually isolated and monitored.<ref>{{Cite web|title=What is a honeypot? How it protects against cyber attacks|url=https://searchsecurity.techtarget.com/definition/honey-pot|access-date=2021-03-04|website=SearchSecurity|language=en}}</ref> 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 [[Exploit (computer security)|exploitation]] techniques. Such analysis may be used to further tighten security of the actual network being protected by the honeypot. A honeypot can also direct an attacker's attention away from legitimate servers. A honeypot encourages attackers to spend their time and energy on the decoy server while distracting their attention from the data on the real server. Similar to a honeypot, a [[honeynet]] is a network set up with intentional vulnerabilities. Its purpose is also to invite attacks so that the attacker's methods can be studied and that information can be used to increase network security. A honeynet typically contains one or more honeypots.<ref>{{cite web|url=http://www.honeypots.net |title=''Honeypots, Honeynets'' |publisher=Honeypots.net |date=2007-05-26 |access-date=2011-12-09}}</ref>

Previous research on network security was mostly about using tools to secure transactions and information flow, and how well users knew about and used these tools. However, more recently, the discussion has expanded to consider [[information security]] in the broader context of the [[digital economy]] and society. This indicates that it's not just about individual users and tools; it's also about the larger culture of information security in our digital world.<ref>{{Cite journal |last1=Krawczyk-Sokołowska |first1=Izabela |last2=Caputa |first2=Wiesława |date=2023-05-01 |title=Awareness of network security and customer value – The company and customer perspective |journal=Technological Forecasting and Social Change |volume=190 |pages=122430 |doi=10.1016/j.techfore.2023.122430 |issn=0040-1625 |pmc=9982364 |pmid=36883131}}</ref>

==Security management==
Security management for networks is different for all kinds of situations. A home or small office may only require basic security while large businesses may require high-maintenance and advanced software and hardware to prevent malicious attacks from [[Hacker (computer security)|hacking]] and [[spamming]]. In order to minimize susceptibility to malicious attacks from external threats to the network, corporations often employ tools which carry out network security verifications].
Andersson and Reimers (2014) found that employees often do not see themselves as part of their organization's information security effort and often take actions that impede organizational changes.<ref>Reimers, Karl; Andersson, David (2017). Post-secondary Education Network Security: the End User Challenge and Evolving Threats. ICERI2017 Proceedings. Vol. 1. IATED. pp. 1787–1796. doi:10.21125/iceri.2017.0554. ISBN 978-84-697-6957-7. ISSN 2340-1095</ref>

===Types of attack===
Networks are subject to [[Attack (computing)|attacks]] from malicious sources. Attacks can be from two categories: "Passive" when a network intruder intercepts data traveling through the network, and "Active" in which an intruder initiates commands to disrupt the network's normal operation or to conduct reconnaissance and lateral movements to find and gain access to assets available via the network.<ref>Wright, Joe; Jim Harmening (2009) "15" Computer and Information Security Handbook Morgan Kaufmann Publications Elsevier Inc p. 257</ref>

Types of attacks include:<ref>{{cite web |url=http://www.cnss.gov/Assets/pdf/cnssi_4009.pdf |title=BIG-IP logout page |publisher=Cnss.gov |date=1970-01-01 |access-date=2018-09-24 |archive-url=https://web.archive.org/web/20120227163121/http://www.cnss.gov/Assets/pdf/cnssi_4009.pdf |archive-date=2012-02-27 |url-status=dead }}</ref>

* Passive
** Network
*** {{Annotated link |Telephone tapping|Wiretapping}}
*** {{Annotated link |Port scanner|Passive Port scanner}}
*** {{Annotated link |Idle scan}}
*** {{Annotated link |Encryption}}
*** {{Annotated link |Traffic analysis}}
* Active:<span class="plainlinks"></span>
** [[Network virus]] (router viruses)
** {{Annotated link |Eavesdropping}}
** Data modification 
{{columns-list|colwidth=30em|
 * [[Denial-of-service attack]]
** {{Annotated link |Port scanner|Active Port scanner}}
** {{Annotated link |DNS spoofing}}
** {{Annotated link |Man-in-the-middle attack|Man in the middle}}
** {{Annotated link |ARP poisoning}}
** {{Annotated link |VLAN hopping}}
** {{Annotated link |Smurf attack}}
** {{Annotated link |Buffer overflow}}
** {{Annotated link |Heap overflow}}
** {{Annotated link |Format string attack}}
** {{Annotated link |SQL injection}}
** {{Annotated link |Phishing}}
** {{Annotated link |Cross-site scripting}}
** {{Annotated link |CSRF}}
** {{Annotated link |Cyber-attack}}
}}

==See also==
{{columns-list|colwidth=30em|
* {{Annotated link |Cloud computing security}}
* {{Annotated link |Computer security}}
* {{Annotated link |Crimeware}}
* {{Annotated link |IT security standards}}
* {{Annotated link |Data loss prevention software}}
* {{Annotated link |Greynet}}
* {{Annotated link |Identity-based security}}
* {{Annotated link |IDN homograph attack}}
* {{Annotated link |Metasploit Project}}
* {{Annotated link |Mobile security}}
* {{Annotated link |Network enclave}}
* {{Annotated link |Network Security Toolkit}}
* {{Annotated link |TCP Gender Changer}}
* {{Annotated link |TCP sequence prediction attack}}
* {{Annotated link |List of security hacking incidents}}
* {{Annotated link |Wireless security}}
* {{Annotated link |Dynamic secrets}}
* {{Annotated link |Low Orbit Ion Cannon}}
* {{Annotated link |High Orbit Ion Cannon}}
* {{Annotated link |Gordon–Loeb model}}
}}

==References==
{{reflist}}

==Further reading==
*[http://www.scmagazine.com/case-study-network-clarity/article/324988 ''Case Study: Network Clarity''] {{Webarchive|url=https://web.archive.org/web/20160527070056/http://www.scmagazine.com/case-study-network-clarity/article/324988/ |date=2016-05-27 }}, SC Magazine 2014
*Cisco. (2011). What is network security?. Retrieved from [http://www.cisco.com/cisco/web/solutions/small_business/resource_center/articles/secure_my_business/what_is_network_security/index.html cisco.com] {{Webarchive|url=https://web.archive.org/web/20160414004501/http://www.cisco.com/cisco/web/solutions/small_business/resource_center/articles/secure_my_business/what_is_network_security/index.html |date=2016-04-14 }}
*[http://www.cert.org/encyc_article/tocencyc.html Security of the Internet] (''The Froehlich/Kent Encyclopedia of Telecommunications vol. 15''. Marcel Dekker, New York, 1997, pp.&nbsp;231–255.)
*''[http://www.interhack.net/pubs/network-security Introduction to Network Security] {{Webarchive|url=https://web.archive.org/web/20141202191427/http://www.interhack.net/pubs/network-security/ |date=2014-12-02 }}'', Matt Curtin, 1997.
* ''Security Monitoring with Cisco Security MARS'', Gary Halleen/Greg Kellogg, Cisco Press, Jul. 6, 2007. {{isbn|1587052709}}
* ''Self-Defending Networks: The Next Generation of Network Security'', Duane DeCapite, Cisco Press, Sep. 8, 2006. {{isbn|1587052539}}
* ''Security Threat Mitigation and Response: Understanding CS-MARS'', Dale Tesch/Greg Abelar, Cisco Press, Sep. 26, 2006. {{isbn|1587052601}}
* ''Securing Your Business with Cisco ASA and PIX Firewalls'', Greg Abelar, Cisco Press, May 27, 2005. {{isbn|1587052148}}
* ''Deploying Zone-Based Firewalls'', Ivan Pepelnjak, Cisco Press, Oct. 5, 2006. {{isbn|1587053101}}
* ''Network Security: PRIVATE Communication in a PUBLIC World'', Charlie Kaufman | Radia Perlman | Mike Speciner, Prentice-Hall, 2002.  {{isbn|9780137155880}}
* ''Network Infrastructure Security'', Angus Wong and Alan Yeung, Springer, 2009. {{isbn|978-1-4419-0165-1}}

{{Computer security}}
{{Authority control}}

[[Category:Computer network security| ]]