Network Security

Threat

A threat is a potential violation of security. When a threat is executed it becomes attack and those who execute such threats are called attackers.

Some common threats average computer user faces everyday are:

Computer viruses- Computer viruses are malicious codes that cause damage to data and files on a system. It can attack any part of a computer's software such as boot block, operating system areas, files and application programs macros etc.

There are also two other similar programs that work like virus are:

Worms- These are self-replicating program which eats up entire disk space or memory

Trojan horses- These programs appear harmless but actually perform malicious functions such as deleting or damaging files.

Damaged caused by viruses are:

Damage or delete files
Slow down computer
Invade (attack) email program

Spyware- Spyware is a software which spy on users activity and report this data to people willing to pay for it.

Damage caused by spyware:

Compromises your data, computing habits and Identity
Altars PC settings
Slowdown PC

Adware- These are the programs that deliver unwanted ads in popup form and consume network bandwidth. Adware is similar to spyware however it may be installed with the user consent.

Damage caused by adware:

Track information just like spyware
Displays array of annoying advertising
Slowdown PC

Spamming- Spamming refers to sending bulk email by an identified or unidentified source.

Damage caused by spamming:

Reduce productivity
Eats up your time
Leads to worse things

PC intrusion- When a PC is connected to the internet, it is a potential target for hackers. PC intrusion can occur in any of the following forms.

Sweeper attack- It is a malicious program used by hackers to sweeps or deletes all the data from a system.
Daniel of services- This attack eats up all the resources such as processor, RAM etc. and stop application to work properly. Flooding of junk mail is an example of such an attack.
Password guessing- Most hackers crack or guess password of system accounts and use it for causing damages.
Snooping- Snooping refers to opening and looking through files in an unauthorised manner. It involves monitoring of keystrokes pressed, capturing of passwords and login information etc.
Eavesdropping- It is similar to snooping and it is used to listen to the conversation that they are not part of. It is called eavesdropping
Phishing- Phishing is the criminal criminally fraudulent process of attempting to acquire sensitive information such as username, password, credit card information etc. In Phishing an imposter uses an authentic-looking email or website to trick recipients into giving out personal information and later it is used for cybercrimes and frauds.

Network security measures- When we go online we need a combination of identification, authentication and authorisation to control access to the system. We can use various techniques for network security:

Authorisation- Asking a user a legal login ID performs at the authorisation
Authentication- Authentication is also termed as password protection
Firewall- A system designed to prevent unauthorised access to or from a public or private network is called firewall.
Intrusion(Violation) detection- Intrusion detection system monitor system and network resources and when it is identified as a possible intrusion then it notifies the authorities.

Also we can implement preventive measure such as:

Implement proper security policy for your organisation
Use proper file access permissions when sharing files on network
Disconnect from the internet when away

UNIT-302
Network Operating System Administration

Network Security

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