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The purpose of this paper is making awareness of Network security and its consequences on organizations and people. The paper abstracts mostly details about what are the types of attacks on networks and how to make preventions before attacks.
While computer systems today have some of the best security systems ever, they are more vulnerable than ever before. This vulnerability stems from the world-wide access to computer systems via the Internet.
Network security addresses the vulnerabilities to which your organization is exposed as a consequence of being connected to a network.
In the field of networking, the specialist area of network security consists of the provisions and policies adopted by the network administrator to prevent and monitor unauthorized access, misuse, modification, or denial of the computer network and network-accessible resources.
An overview and some more aspects on the network security are described below.
Network Security is protecting a network from unwanted intruders.
Who are vulnerable?
In organization everyone who uses computer for their job, who stores inform ions in computers.
Customers or outsiders who rely on this organization.
Servers and End-Users are also exposed to network security.
Examples of servers are network devices, file servers, e-mail servers, web servers etc.
End-users are those who receive e-mail, visit web sites, download files, pursue in online services
Everyone is vulnerable by threats:
Through e-mail (e.g. worms, viruses)
Through web-browsers (e.g. malicious scripts and applets)
Simply being connected to network (breaking , protocol hacks)
Following are some of the examples of network security attacks in past decades
20-year-old man arrested for breaking into two computers of NASA's Jet Propulsion Laboratory.
Hacker boosted stock price by posting fake merger press release.
A hacker boosted the stock of Aastrom Biosciences by 6.5% by posting a fake press release on the company's Web site announcing a merger with California biopharmaceutical company Geron.
Thousands of Safeway customers received emails that appeared to come from the company, saying Safeway would raise its prices by 25 percent. The emails also said, "If you wanted to shop elsewhere, you could."
Safeway shut down U.K. site after hacker attack on August 12, 2000
Attacks from within
These attackers originate from inside the intranet/LAN, a "trusted source"
"From case studies it is shown that a majority of attacks originate from within an organization. Some studies showed that as much as 70% of all attacks from someone within an organization or from someone with inside information (such as an ex-employee)."
Sometimes the damage is done without intent
Sometimes the damage is done on purpose
Acts of vandalism
Snoop attacks from nosey co-workers
Malicious attacks from disgruntled people such as ex-employees.
Attacks from the Outside
These attackers originate from anyone/anyplace outside of your LAN/intranet, an unknown source.
Sometimes the damage is done without intent....
Sometimes the damage is done on purpose.
Why outsiders attack?
To steal information, real assets/money or services.
To corrupt or destruction the data of an organization
To simply say "I did it!" known as bragging rights.
For defacement or vandalism
To corrupt operational systems controlled by computers (TV systems, phone system etc.)
They plant bots which can be remotely activated and controlled to accomplish any of the attacks listed above using your machine as the host
Types of attacks
Denial of Service (DoS) attacks
DoS attacks have following goals.
To crash host
To flood host
To flood the network connected to host
Virus attaches itself to files on the target machine
Master Boot Sector/Boot Sector viruses
File viruses, Macro viruses
Stealth viruses, Polymorphic viruses
Worms, Trojans and Backdoors
Trojans are programs that appear to perform a desirable and necessary function that perform functions unknown to (and probably unwanted by) the user.
Unlike a virus, worms are a memory resident virus which seeds itself in the computer's hard disk or file system; it will only maintain a functional copy of itself in active memory.
Worms frequently "sleep" until some event triggers their activity - send password or registry to hacker.
Worms and Trojans frequently enable Backdoors on a system which allows hidden access and control of a system.
Scanners are the programs that automatically detect security weaknesses in remote or local hosts.
Tells the hacker:
What services are currently running and who are owners of them and whether certain network services require authentication.
If anonymous logins are supported or not.
Actually try to decrypt.
Most simply try "brute force" or intelligent "brute force"
Dictionary words, days of year, initials
These are the devices that capture the packets of network.
They are extremely difficult to detect due to their passiveness.
Measures of protection
One product cannot provide full protection because computer networking environment consists of many different subsystems for one product to provide full protection
Ethernet protocol, IP protocol, TCP protocol, Routing protocols, Operating Systems
Presentation protocols such as HTML, DHTML, XHTML, XML
Applications - MS Outlook, Netscape Communicator, server SW (MS IIS, etc.)
Make sure it is set to scan all executables, compressed files, e-mail, e-mail attachments, web pages
Keep up to date virus information files!
E-mail Server filters
They provide protection for e-mail passing through the server
Integrate directly with the E-mail Server software - MS Exchange, Lotus Notes, Netscape, and cc: Mail, etc.
Example products: McAfee GroupShield, Trend Micro ScanMail
Web based protection filters
"A combination of hardware and software resources positioned between the local (reliable) network and an unreliable network.
Firewalls track and control communications, deciding whether to pass, reject, encrypt, or log communications."
Web Server protection
It protects web server from hacking (e.g. AppShield (Sanctum Inc.))
Web Access Control
Restricts web sites to which you can connect. Can protect you by not allowing you to go to malicious web sites (e.g. WebSENSE)
As we can see that network security threats are becoming major problem for the network users. So an awareness or knowledge of network security threats such as worms, viruses, backdoors, crackers, etc. is required to prevent network affection. We should be careful while using LAN/intranet and internet and especially when we make online money transaction such as online banking or other transactions and also when using email facilities and surfing.