Email About Computer Viruses example essay topic

SECTION A METHODOLOGY INDEX BASED (DIRECTORIES) HIGHLIGHTS OF ALTAVISTA. META SEARCH SITES SECTION B IV FIREWALLS. IV WHAT IS A FIREWALL? IV WHAT IS ENCRYPTION? IV HOW IT WORKS. IV HOW IS IT OVERCOME?

IV FILTERING SOFTWARE V WHAT IS FILTERING SOFTWARE? V HOW IT WORKS V KEYWORD BLOCKING V SITE BLOCKING V WEB RATING SYSTEMS V SOME EXAMPLES OF FILTERING SOFTWARE: V COMPUTE VIRUSES VI WHAT IS A COMPUTER VIRUS? VI DIFFERENT TYPES OF VIRUSES VI HOW DO YOU RECOGNISE A HOAX? VII WHAT IS DIGITAL SIGNATURE? V HOW DIGITAL SIGNATURES ARE CREATED V STEP 1 THE HASH V STEP 2 ENCRYPTION V STEP 3 CERTIFICATION IX HOW IT WORKS IX A DIGITAL SIGNATURE MIGHT LOOK LIKE THIS. X CAN THEY BE INTERFERED WITH?

X SECTION C XI TERMS OF REFERENCE XI FINDINGS. XI 1) HOW INFECTION OCCURS XI 2) PARASITE VIRUSES XI HOW THEY ATTACK XI MACRO VIRUSES XII WHAT ARE THEY? XII 4) BOOT SECTION VIRUSES XII WHAT IS THE BOOT SECTOR? XII TROJAN HORSE XII WORMS XII 5) E-MAIL VIRUSES XII CONCLUSIONS X RECOMMENDATIONS X BIBLIOGRAPHY XIV SECTION A METHODOLOGY Index Based (Directories) Index sites use web-indexing robots or (web crawler / spider as they are typically referred to in the search world) The crawler collects documents from the web to build the index. It is a software programme designed to follow hyperlinks through a web site, retrieving and indexing pages to document the site for searching purposes. The crawler goes to a web address (URL) and downloads the HTML page.

The Data Base Associated with these search engines is divided into several categories, and sub categories according to how they gather information. This allows the searcher to search for results in an organised fashion. Directories such as Alta Vista are good at identifying general information; a search for the phrase "Internet firewalls" produced a result of 17,640 while Yahoo returned 44,200 though Yahoo returned the most results Alta Vista results were more relevant to my search. Highlights of AltaVista.

Delivers Internet's first Web index (1995) First multilingual search capabilities on the Internet First Internet search engine to launch Image, Audio, and Video search capabilities Most advanced Internet search features and capabilities: multimedia search, translation and language recognition, and speciality search Index Search Engines will find individual Web Pages that contain the words the user searched for, and rank them in importance according to the number of times the word appears on a page Other index sites are Google and Ask Jeeves. META SEARCH SITES Meta Search Sites send searches to several Search Engines. These Engines do not allow for input of many search variables, however their best use is to find information on obscure topics, or to see if something is available on the Internet. SECTION B FIREWALLS. What is a firewall? Firewall definition - a computer network firewall is an electronic blocking mechanism that will not allow unauthorised intruders into a computer system.

A computer firewall is a software programme that blocks potential hackers from individual computers or computer networks. Basically, a firewall is a barrier to keep destructive forces away from your property. In fact that is why it is called a firewall its job is similar to a physical firewall that keeps a fire from spreading from one area to the next. Technologies like IPP (Internet Printing Protocol) and Web DAV (Web-based Distributed Authoring and Versioning) are designed to skirt firewall configurations, while other protocols billed as "firewall friendly" actually circumvent them, to provide rapid access. Even when firewalls are in place, It is difficult to rely on them to block the onslaught of tainted packets, because the packets' addresses constantly change, Encryption What is Encryption? Encryption is a code.

It allows the storing of information on paper or anywhere else in a form, which allows only authorised personnel to understand and use it. If an unauthorised person were to look at the information they would only see sequences of meaningless characters and symbols. How it works. An Encryption System is designed so that the process of converting the Encryption information is allowed only under two conditions. The first of these conditions is that the person attempting to decrypt the information must have the Encryption System, which in modern times is likely to be a specially designed computer programme. The second condition is that the person must also have a piece of information called Encryption's Keys (specifically devised codes).

How is it overcome? The first common method of attack is called brute force attack. This method is used against some common Encryption Systems, where there is knowledge that a certain Key is used to encrypt the plain text and the Hacker also has knowledge of the Algorithm used and possesses an example of the plain text and corresponding cipher text. Algorithm - A procedure or formula for solving a problem. FILTERING SOFTWARE What is filtering software? To restrict access to certain sites it is important to install some Filtering software.

Filtering software is then used to describe the use of software, that restricts access to material on the Internet. This software is used as a method of preventing access to pornography and other offensive material. How it Works Filtering software works in the following way. Keyword Blocking Site Blocking Web Rating Systems. Keyword Blocking Filtering packages use a list of "Forbidden Words" it searches Web Pages, and E-mail messages for these words, if it finds them - it will prevent the user accessing the E-mail, or Web Pages, or will block these relevant parts.

Site Blocking The filtering software Packages, that use site blocking have a list of sites that they will not allow access to, the list normally consists of pornography and other potentially offensive sites. Web Rating Systems These systems are built into Web Pages and Web Browsers. The system works through Web Sites being rated in terms of nudity, sex, violence and language used in them. The ratings are either embedded in the Web Page, or managed by a Rating Bureau. The Web Browser is then set to accept only pages, that are rated at certain levels. Some examples of Filtering Software: Cyber Control Crayon Crawler Net Nanny COMPUTE VIRUSES What is a computer virus?

A computer virus is a computer program that is loaded on to your computer without your knowledge, however the intent is not always to cause damage to your system. The effect of computer viruses varies from doing so little damage that you are unaware that your computer has been infected, to wiping out the entire contents of your hard disk. There are viruses which play music, display messages, change or delete files. Computer viruses are manmade and most are intentionally designed to replicate themselves. When the virus program runs it makes a copy of itself and attaches itself to another computer programme. Each time the infected programme is run, the virus is also run and in this way spreads.

If your system is infected, you can easily spread the virus to others through shared disks and email attachments. Different types of viruses File Infections: A block of code, which attaches itself to another program and is able to copy itself into subsequent applications that you run. Boot-Sector Viruses - infect the area of the hard disk that are read and executed by the computer when it starts up. Macro viruses: Macros are small programs that can be used to carry out tedious repetitive tasks. For example, you can write a Word macro to add your name, address and phone number to documents.

Macros run automatically when the file they are attached to is opened. Macro viruses spread much more rapidly than other forms of viruses as people frequently share data files. The most recent viruses have been spread via email. "The Love Bug" was a macro virus that caused considerable damage. The subject of the email was 'I love you' and had an attached file called 'love-letter-for-you. txt. vbs. ' The attachment was a Visual Basic macro that erased files on your computer.

The virus then sent copies of itself to every address in the Microsoft Outlook address book. As these replicated messages spread they created jams in Internet traffic and the vast amount of mail caused Network servers to crash. It spread round the world in two hours affecting tens of millions of computers. Trojan Horse the term 'Trojan horse' is used to describe a virus program that disguises itself as a benign application.

Trojan horse viruses do not reproduce. Worms are computer viruses that that are designed to copy themselves from one computer to another over a network. Recent viruses designed to be spread via email, e.g. the 'love bug', are 'worms'. The Bubbleboy the latest computer viruses have been email viruses.

Until recently you could not catch a virus by reading an email message. You were only infected if the message had an infected attachment. The 'Bubbleboy' virus was the first email virus that could infect your computer simply by you reading the message. Another similar email virus is the 'kak' virus; it also embeds itself without any email attachment to every email sent from an infected system. Your computer can become infected by a computer virus in a variety of ways: From an infected floppy disk (or any other removable media) e.g. Zip disks, CDs. By opening a file that is infected with a macro virus.

Through email attachments infected with macro viruses. From infected email messages. From hostile Java applets and ActiveX controls, you unknowingly download when browsing the Internet. From infected programs downloaded from the Internet.

VIRUS HOAXES What are they? Warnings sent by email about computer viruses are normally malicious scare alerts. Do not forward these warnings. How do you recognise a hoax?

Check the sender's address. Is the sender a reliable authority on computer viruses? If not it is probably a hoax Check who it has been sent to. If it has been sent to a large group of people then it is probably a hoax. Check the content of the message.

Virus hoaxes often encourage you to forward the message to everyone you know. An example of a typical hoax messages could be; "There is a dangerous virus propagating across the Internet."It has a virus that rewrites your hard drive, obliterating anything on it."There is no remedy or cure". You would then be encouraged to forward the message to all your friends. WHAT IS DIGITAL SIGNATURE?

A reliable electronic means of signing electronic documents that provide sender authentication, message integrity and non-repudiation. A digital signature is an electronic rather than a written signature that can be used by someone to authenticate the identity of the sender of a message or of the signer of a document. It can also be used to ensure that the original content of the message or document that has been conveyed is unchanged. Additional benefits to the use of a digital signature are that it is easily transportable, cannot be easily repudiated, cannot be imitated by someone else, and can be automatically time-stamped. A digital signature can be used with any kind of message, whether it is encrypted or not, simply so that the receiver can be sure of the sender's identity and that the message arrived intact.

A digital certificate contains the digital signature of the certificate-issuing authority so that anyone can verify that the certificate is real. Examples of Digital Signature Applications Emails Electronic Contracts Electronic Application Processes Automated Forms Processing Remote Financial Transaction / Inquiries Any Process Requiring Identification and Authentication How Digital Signatures are created There are three steps to creating a Digital Signature. Step 1 The Hash Fingerprinting Electronic Data, using a Mathematical Formula known as Hash Algorithm creates a Digital Signature. Step 2 Encryption The second element in Digital Signature is Encryption. The simplest form of Encryption is where one letter is substituted for another. Step 3 Certification This is the final stage in creating a Digital Signature.

Certification involves the existence of a trusted Third Party, generally known as Certificate authority, which confirms the identity of the signer. Certificates are similar to other forms of Personal Identification. How It Works Assume you were going to send the draft of a will to your solicitor in another town. You want to assure your solicitor that the document he receives is from you and still contains its original content.

So this is how you send it: You copy-and-paste the will into an e-mail note. Using special software, you obtain a message hash (mathematical summary) of the will. You then use a private key that you have previously obtained from a public-private key authority to encrypt the hash. The encrypted hash becomes your digital signature of the message.

(Note that it will be different each time you send a message. ). At the other end, your solicitor receives the message: To make sure it is intact and from you, your lawyer makes a hash of the received message. Your solicitor then uses your public key to decrypt the message hash or summary. If the hashes match, the received message is valid.

A Digital Signature might look like this.'s IG ' Begin signature block's IG ' MISC 8 AYJKoZIhvcNAQcCoIIC 4 TCC At 0 CAQExDjAMBggq's IG ' haig 9 w 0 CBQUAMGYGCisGAQQBgjcCAQSgWDBWMDIGCisG's IG ' AQQBgjcCAR 4 wJAIBA TvApFpkntU 2 P 5 azhDxfrqwIB's IG ' AAIBAAIBAAIBAAIBADAgMAwGCCqGSIb 3 DQIFBQAEEPC 2's IG ' Q dSn 0 Xn jl 7 nT / Xw adl 2 F 6 MIIBdjCCASCgAwIBAgIQ's IG ' NeMgQmXo 1 o 1 F 8 M 6 hs 6 TX 1 jANBgkqhkiG 9 w 0 BAQQFADAW's IG ' MRQwEgYDVQQDEwtSb 290 IEFnZW 5 jeTAeFw 0 wMDEyMjEy's IG ' MzUxMTJaFw 0 zOTEyMzEyMzU 5 NTlaMBUxEzARBgNVBAMT's IG ' Ck 15 IENvbXBhbnkwXDANBgkqhkiG 9 w 0 BAQEFAANLADBI's IG ' Ak EAx / b BOOqOzdHk 2 EfxXloUaGo 9 PtI / HS 9 LQSXkhF 7's IG ' need 4 Qy+oyA 7 NImnOacI+1 HDCOAPeKgGJIvaFcZs 0 BuM's IG ' iQIDAQABo 0 swSTBHBgNVHQEEQDA+gas 5 Ak tBh 0 dTw CN's IG ' YSHcFmRjoRgwFjEUMBIGA 1 UEAxMLUm 9 vdCBBZ 2 Vue 3 mC's IG ' WAY 3 bACqAGSKEc+41 KpcNfQwDQYJKoZIhvcNAQEEBQAD's IG ' QA 6/fIIDKycSp 2 Debt / A 3 iUSxoiu 2 BqmEEpVoGKE 5 yY's IG ' CA 3 MD WuI 29 RRvgNJ 2 oQ asb 8 raid 5 dEexGK 3 rWEQGV 6 r+'s IG ' MYHhMIHeAgEBMCowFjEUMBIGA 1 UEAxMLUm 9 vdCBBZ 2 Vu's IG ' Y 3 kCEDXjIEJl 6 NaNRfDOobOk 19 YwDAYIKoZIhvcNAgUF's IG ' AKBOMBAGCisGAQQBgjcCAQwxAjAAMBkGCSqGSIb 3 DQ EJ's IG ' AzEMBgorBgEEAYI 3 AgE EMB 8 GCSqGSIb 3 DQEJBDESBBCV's IG ' t 6 own 7 YLnkAnCqiDdINMA 0 GCSqGSIb 3 DQEBAQUABECe's IG ' xmfNlmrIls 2 kFkyhXOWKicnpOk 5 iW 4 twTRNAc 4 Lake 8 M's IG ' uk 0 ZBCBgR 5 XC 8 F 7 slEMfWCG 9 R 7129 EUR 4 vFhZToK's IG ' End signature block Can they be interfered with? No, Digital Signatures cannot be interfered with because - the signature is created with the person's unique key and can be verified by the recipient using the Senders Public Key. SECTION C Terms of Reference A report to investigate the spread of computer viruses. What they are how they spread and how to prevent and fix them. FINDINGS.

A Computer virus is a special type of Programme, which spreads itself across disks and networks by making copies of itself. The virus can produce undesired side effects in computers in which it is active. 1) How Infection Occurs A Virus that is active on the computer can copy itself to infect other sites, files or disks as the user accesses them. Different types of viruses infect Computers in particular ways.

The most widespread types are Macro, Boot and Parasite Viruses. Two brothers who were dissatisfied with Computer Privacy produced 0 ne of these viruses in the mid-eighties, and wrote the first computer virus, a boot sector virus called Brian. From this an entire counter culture grew the creation and distribution of computer viruses became an industry in itself. Today these viruses number in the tens of thousands. 2) Parasite Viruses How They Attack Parasite Viruses attach themselves to programmes also known as executables (exe). When a user launches a programme that has a parasite virus, the virus is surreptitiously launched first.

To hide its presence from the user, the virus then triggers the original programme to open. The operating system assumes the virus is part of the programme. The virus is given the same rights as the programme to which it is attached. This allows the virus to replicate and install itself into the memory, or releases a payload - this causes delays on every programme the user launches.

Macro Viruses What Are They? A macro is an instruction that carries out programme commands automatically. Macro viruses self-replicate when a user accesses a document with a viral macro, and unwittingly executes this macro virus, it can copy itself and infect any application's start-up files. If the computer is infected, and it is connected to a network. The virus will spread to the other network machines. 4) Boot Section Viruses What is The Boot Sector?

The boot sector is the first software loaded onto the computer. It is not possible to run a computer without this software. This programme resides on a disk, either the hard disk a floppy disk or a compact disk. A boot sector virus can only infect a machine if it is used to boot-up a computer, for example if you start a computer by using a floppy disk with an infected boot sector, your computer could be infected.

Trojan Horse A Trojan Horse is a normal programme. It claims to be a game, when the programme is run it will do damage. For example it will erase the hard disk Trojan horses cannot replicate themselves. Worms A worm is a small piece of software that uses computer networks and security holes to copy itself.

A copy of the worm scans the network for a machine that has a specific security hole, and then it copies itself to that machine, using the security hole it continues to copy itself. Code Red was a worm; experts thought would clog the networks and bring them to a halt. Microsoft released a simple patch that blocked the security hole effectively blocking the worm. 5) E-mail Viruses How Do They Arrive?

E-mail Viruses generally arrive in an attachment, if a document attachment is infected the virus then attaches itself to the recipient's mailing list and the user then unwittingly passes it on. Conclusions A computer with an active copy of a virus is considered infected. The virus becomes active depending on the way it was designed. Macro viruses depend on the user to open the programme. Viruses can be hidden in programmes available on floppy disks, CD or in e-mail attachments and material downloaded from the web. Computer viruses are widespread; some can damage your work others are just frustrating they tend to be the ones that continuously display unwanted messages.

Lots of viruses are destructive, and erase or damage files. The most common of these viruses affect word-processing and spreadsheet files. Recommendations Install Anti-Virus software on your computer. Keep it updated this will report and disinfect viruses. (eg...

Norton McAfee). Save everything of importance to secondary storage i.e. floppy disk CD or Zip drive. Users should always take the precaution of scanning disks before use, sharing disks is not a good idea, down loading from the Internet and opening e-mail attachments from unknown sources also increases the risk of infection. I strongly recommend. Word and Excel files should be scanned before opening. Scan all disks that have been used on other computers Avoid opening e-mails from unknown sources.

Do not share commercial software. Bibliography web web web web web web. /learnthenet. com / english /animate / encrypt. html web web.