Search Engines and Cyber Hygiene Exercise - 11
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IT WORKSHOP LAB MANUAL Search Engines and Cyber Hygiene Exercise - 11 Aim: Working of search engine, Awareness of various threats on Internet, types of attacks and how to overcome. Installation of antivirus software, configuration of personal firewall and Windows update on computers. 11.1 Introduction Search Engine refers to a huge database of internet resources such as web pages, newsgroups, programs, images etc. It helps to locate information on World Wide Web. User can search for any information by passing query in form of keywords or phrase. It then searches for relevant information in its database and return to the user. Fig. 1. Windows explorer 198 Prepared by: APPROVED BY : Ms.K.NIRMALA Dr.K.RAMANI Mr.V.S.V.S.S.S.M.CHAKRADHAR HOD, IT IT WORKSHOP LAB MANUAL Search Engine Components Generally there are three basic components of a search engine as listed below: 1. Web Crawler 2. Database 3. Search Interfaces Web crawler It is also known as spider or bots. It is a software component that traverses the web to gather information. Database All the information on the web is stored in database. It consists of huge web resources. Search Interfaces This component is an interface between user and the database. It helps the user to search through the database. Search Engine Working Web crawler, database and the search interface are the major component of a search engine that actually makes search engine to work. Search engines make use of Boolean expression AND, OR, NOT to restrict and widen the results of a search. Following are the steps that are performed by the search engine: The search engine looks for the keyword in the index for predefined database instead of going directly to the web to search for the keyword. It then uses software to search for the information in the database. This software component is known as web crawler. Once web crawler finds the pages, the search engine then shows the relevant web pages as a result. These retrieved web pages generally include title of page, size of text portion, first several sentences etc. These search criteria may vary from one search engine to the other. The retrieved information is ranked according to various factors such as frequency of keywords, relevancy of information, links etc. User can click on any of the search results to open it. 199 Prepared by: APPROVED BY : Ms.K.NIRMALA Dr.K.RAMANI Mr.V.S.V.S.S.S.M.CHAKRADHAR HOD, IT IT WORKSHOP LAB MANUAL 11.2 INTRODUCTION TO VARIOUS THREATS ON INTERNET A web threat is any threat that uses the internet to facilitate cybercrime. Web threats use multiple types of malware and fraud, all of which utilize HTTP or HTTPS protocols, but may also employ other protocols and components, such as links in email or IM, or malware attachments or on servers that access the Web. Web threats pose a broad range of risks, including financial damages, identity theft, loss of confidential information/data, theft of network resources, damaged brand/personal reputation, and erosion of consumer confidence in e-commerce and online banking. 11.2.1 TYPES OF INTERNET THREATS Viruses Network Worms Trojans Spyware / Adware Other Malware Other Threats Viruses A virus is a program that replicates itself, usually by attaching itself to other files and programs. A worm is a program that does not infect other programs but makes copies of itself. Trojan horse programs do not replicate nor make copies of themselves, but rely on other "manual" methods of distribution. We use the term "viruses" on this page to cover all forms of infections. Viruses are spread in a variety of ways. Some Examples: • email attachments (such as Klez, Badtrans, MyParty) • instant messaging links and attachments (such as Aplore) • compromised web servers (such as Nimda) • Usenet news groups • Inernet Relay Chat channels • floppy diskettes • file downloads (many backdoor Trojans are embedded with other files) 200 Prepared by: APPROVED BY : Ms.K.NIRMALA Dr.K.RAMANI Mr.V.S.V.S.S.S.M.CHAKRADHAR HOD, IT IT WORKSHOP LAB MANUAL Fig. 2. viruses All viruses are different. Some activate on a certain day, but remain dormant until then. Others begin the attack as soon as the machine has been infected. Viruses can be very damaging and some are just annoying. More than 1,00,000 known viruses exists in the world today Several hundred new viruses are discovered every month Protecting from viruses: A good way to protect yourself is to have a virus protection program and keep it up- to-date. Before running a download from an unknown site, or opening an email attachment, always be sure to scan it to ensure that it is not infected. If you do not know the source of a file do not open it. Even if you know the person who sent you a file, if you were not expecting it you may want to contact them before opening it. This is because many viruses automatically send themselves out to addresses it finds in files on the infected computer. Fig. 3. virus protection Anti-virus program: An anti-virus program is designed to protect your computer from possible virus infections. Most viruses are designed to operate in the background in a way that the user will not notice. Virus protection programs search for, detect, and attempt to remove these viruses. 201 Prepared by: APPROVED BY : Ms.K.NIRMALA Dr.K.RAMANI Mr.V.S.V.S.S.S.M.CHAKRADHAR HOD, IT IT WORKSHOP LAB MANUAL Anti-virus programs must be kept up-to-date in order for them to provide adequate protection. New viruses are being created every day and your anti-virus program can't always predict what they will be able to do or how they will work. Due to the nature of the operating system, Linux, and other UNIX-like operating systems are not as susceptable to viruses. Thus an anti-virus program is not necessary. Network Worms Network Worm is a Self-replicating Viruses that reside in the active memory of a computer. A worm is a computer program that has the ability to copy itself from machine to machine. Worms use up computer processing time and network bandwidth when they replicate, and often carry payloads that do considerable damage. Worms send themselves out to the Internet from infected systems. Either include tiny e-mail server or search for unprotected shared network drives to unload. Trojan Programs: Trojan, is a standalone malicious program that does not attempt to infect files unlike a computer virus or replicate itself with the intent of infecting other computers unlike a computer worm. Trojan horses can make copies of themselves, steal information, or harm their host computer systems Trojan horses are often destructive programs that masquerade as benign applications. Unlike viruses and worms, Trojan horses do not replicate themselves, but they can be just as destructive. One of the most insidious types of Trojan horse is a program that claims to get rid of viruses but instead introduces viruses onto the computer. • Threats enabled by (/through) Trojans � DDos attacks � Data stealing � Distributed spam eMails Spyware / Adware: • Cookies – Track you online • Browser Hijackers – Changes default home page • Tracking Cookies – Gathers info of web usage • Trickles – Reinstalls spyware when deleted • Keyloggers – Records anything you type! …. Etc. 202 Prepared by: APPROVED BY : Ms.K.NIRMALA Dr.K.RAMANI Mr.V.S.V.S.S.S.M.CHAKRADHAR HOD, IT IT WORKSHOP LAB MANUAL Other malware: • Dos & DDos attacks • Flooders • FileCryptors & PolyCryptors • Nukers … Etc. Other Threats: • Phishing � Confidential information stealing by fraud emails & web sites (author falsified) � Several millions of Phishing messages have been sent world wide � Fastest growing threat today • SPIM � Instant Messaging SPAM � Estimated: 4 billion SPIM's during 2004 Diagnosing Infections: • Slow computer, system reboots • Mouse moves by itself • Browser goes to unexpected web sites • Slow internet access • Endless popup ads • New desktop toolbars Solutions to Overcome: • Disabled antivirus scanner or firewall • Check startup program group regularly for software you didn’t install • Check Add/Remove programs for software you didn’t install (make a list of installed items on a new machine and check the list regularly) • Check running services monthly • Check running processes in Task Manager • Monitor open ports • Monitor outgoing and incoming connections 203 Prepared by: APPROVED BY : Ms.K.NIRMALA Dr.K.RAMANI Mr.V.S.V.S.S.S.M.CHAKRADHAR HOD, IT IT WORKSHOP LAB MANUAL Anti-Virus Software: Antivirus software is used to prevent, detect, and remove malware, including but not limited to the computer viruses, computer worms, Trojan horses, spyware and adware. Computer security, including protection from social engineering techniques, is commonly offered in products and services of antivirus software companies. Some of the Antivirus software’s • Norton Anti-Virus • McAfee Anti-Virus • AVG Anti-Virus 11.3 INSTALLATION OF ANTI-VIRUS Steps for installing antivirus software Head over to the Microsoft Security Essentials page and download the software. Double-click on the installer to begin the installation process. The installation should be pretty self-explanatory. Just follow the steps it gives you. Make sure you've checked the box to turn on the Windows Firewallwhen prompted, and give the whole thing a few minutes to install. When it's done, it will ask you to run a scan. Hit yes, and it will download the latest virus definitions and run its first scan. All of this will take a few minutes, so just leave the program alone and let it do its thing. When it's finished it's scan (hopefully without finding anything), it will begin monitoring your computer.