1. Security Awareness Chapter 3 Internet Security

2. O BJECTIVES After completing this chapter, you should be able to do the following:  Explain how the World Wide Web and e-mail work  List the different types of Internet attacks  Explain the defenses used to repel Internet attacks S ECURITY A WARENESS, 3 RD E DITION 2

3. H OW THE I NTERNET W ORKS  Internet  Worldwide set of interconnected computers, servers, and networks  Not owned or regulated by any organization or government entity  Computers loosely cooperate to make the Internet a global information resource S ECURITY A WARENESS, 3 RD E DITION 3

4. T HE W ORLD W IDE W EB  World Wide Web (WWW)  Better known as the Web  Internet server computers that provide online information in a specific format  Hypertext Markup Language (HTML)  Allows Web authors to combine text, graphic images, audio, video, and hyperlinks  Web browser  Displays the words, pictures, and other elements on a user’s screen S ECURITY A WARENESS, 3 RD E DITION 4

5. T HE W ORLD W IDE W EB ( CONT ’ D.) Figure 3-1 How a browser displays HTML code S ECURITY A WARENESS, 3 RD E DITION 5 Course Technology/Cengage Learning

6. T HE W ORLD W IDE W EB ( CONT ’ D.)  Hypertext Transport Protocol (HTTP)  Standards or protocols used by Web servers to distribute HTML documents  Transmission Control Protocol/Internet Protocol (TCP/IP)  Port number  Identifies the program or service that is being requested  Port 80 Standard port for HTTP transmissions S ECURITY A WARENESS, 3 RD E DITION 6

7. T HE W ORLD W IDE W EB ( CONT ’ D.)  Transfer-and-store process  Entire document is transferred and then stored on the local computer before the browser displays it  Creates opportunities for sending different types of malicious code to the user’s computer S ECURITY A WARENESS, 3 RD E DITION 7

8. T HE W ORLD W IDE W EB ( CONT ’ D.) Figure 3-2 HTML document sent to browser S ECURITY A WARENESS, 3 RD E DITION 8 Course Technology/Cengage Learning

9. E-M AIL  Number of e-mail messages sent each day to be over 210 billion  More than 2 million every second  Simple Mail Transfer Protocol (SMTP)  Handles outgoing mail  Post Office Protocol (POP or POP3)  Responsible for incoming mail  Example of how e-mail works S ECURITY A WARENESS, 3 RD E DITION 9

10. E-M AIL ( CONT ’ D.) Figure 3-3 E-mail transport S ECURITY A WARENESS, 3 RD E DITION 10 Course Technology/Cengage Learning

11. E-M AIL ( CONT ’ D.)  IMAP (Internet Mail Access Protocol, or IMAP4)  More advanced mail protocol  E-mail attachments  Documents that are connected to an e-mail message  Encoded in a special format  Sent as a single transmission along with the e- mail message itself S ECURITY A WARENESS, 3 RD E DITION 11

12. I NTERNET A TTACKS  Variety of different attacks  Downloaded browser code  Privacy attacks  Attacks initiated while surfing to Web sites  Attacks through e-mail S ECURITY A WARENESS, 3 RD E DITION 12

13. D OWNLOADED B ROWSER C ODE  JavaScript  Scripting language Similar to a computer programming language that is typically ‘‘interpreted’’ into a language the computer can understand  Embedded in HTML document  Executed by browser  Defense mechanisms are intended to prevent JavaScript programs from causing serious harm  Can capture and send user information without the user’s knowledge or authorization S ECURITY A WARENESS, 3 RD E DITION 13

14. D OWNLOADED B ROWSER C ODE ( CONT ’ D.) Figure 3-4 JavaScript S ECURITY A WARENESS, 3 RD E DITION 14 Course Technology/Cengage Learning

15. D OWNLOADED B ROWSER C ODE ( CONT ’ D.)  Java  complete programming language  Java applet  Can perform interactive animations, immediate calculations, or other simple tasks very quickly  Sandbox  Unsigned or signed S ECURITY A WARENESS, 3 RD E DITION 15

16. D OWNLOADED B ROWSER C ODE ( CONT ’ D.) Figure 3-5 Java applet S ECURITY A WARENESS, 3 RD E DITION 16 Course Technology/Cengage Learning

17. D OWNLOADED B ROWSER C ODE ( CONT ’ D.)  ActiveX  Set of rules for how applications under the Windows operating system should share information  Do not run in a sandbox  Microsoft developed a registration system poses a number of security concerns  Not all ActiveX programs run in browser S ECURITY A WARENESS, 3 RD E DITION 17

18. P RIVACY A TTACKS  Cookies  User-specific information file created by server  Stored on local computer  First-party cookie  Third-party cookie  Cannot contain a virus or steal personal information stored on a hard drive  Can pose a privacy risk S ECURITY A WARENESS, 3 RD E DITION 18

19. P RIVACY A TTACKS ( CONT ’ D.)  Adware  Software that delivers advertising content  Unexpected and unwanted by the user  Can be a privacy risk Tracking function  Popup  Small Web browser window  Appears over the Web site that is being viewed S ECURITY A WARENESS, 3 RD E DITION 19

20. A TTACKS WHILE S URFING  Attacks on users can occur while pointing the browser to a site or just viewing a site  Redirecting Web traffic  Mistake when typing Web address  Attackers can exploit a misaddressed Web name by registering the names of similar-sounding Web sites S ECURITY A WARENESS, 3 RD E DITION 20

21. A TTACKS WHILE S URFING ( CONT ’ D.) Table 3-1 Typical errors in entering Web addresses S ECURITY A WARENESS, 3 RD E DITION 21 Course Technology/Cengage Learning

22. A TTACKS WHILE S URFING ( CONT ’ D.)  Drive-by downloads  Can be initiated by simply visiting a Web site  Spreading at an alarming pace  Attackers identify well-known Web site  Inject malicious content  Zero-pixel IFrame Virtually invisible to the naked eye S ECURITY A WARENESS, 3 RD E DITION 22

23. E-M AIL A TTACKS  Spam  Unsolicited e-mail  90 percent of all e-mails sent can be defined as spam  Lucrative business  Spam filters  Look for specific words and block the e-mail  Image spam  Uses graphical images of text in order to circumvent text- based filters S ECURITY A WARENESS, 3 RD E DITION 23

24. E-M AIL A TTACKS ( CONT ’ D.)  Other techniques to circumvent spam filters  GIF layering  Word splitting  Geometric variance  Malicious attachments  E-mail-distributed viruses  Replicate by sending themselves in an e-mail message to all of the contacts in an e-mail address book S ECURITY A WARENESS, 3 RD E DITION 24

25. E-M AIL A TTACKS ( CONT ’ D.)  Embedded hyperlinks  Clicking on the link will open the Web browser and take the user to a specific Web site  Trick users to be directed to the attacker’s “look alike” Web site S ECURITY A WARENESS, 3 RD E DITION 25

26. Figure 3-12 Embedded hyperlink S ECURITY A WARENESS, 3 RD E DITION 26 Course Technology/Cengage Learning

27. I NTERNET D EFENSES  Several types  Security application programs  Configuring browser settings  Using general good practices S ECURITY A WARENESS, 3 RD E DITION 27

28. D EFENSES T HROUGH A PPLICATIONS  Popup blocker  Separate program or a feature incorporated within a browser  Users can select the level of blocking  Spam filter  Can be implemented on the user’s local computer and at corporate or Internet Service Provider level S ECURITY A WARENESS, 3 RD E DITION 28

29. D EFENSES T HROUGH A PPLICATIONS ( CONT ’ D.)  Spam filter (cont’d.)  E-mail client spam blocking features Level of spam e-mail protection Blocked senders (blacklist) Allowed senders (whitelist) Blocked top level domain list  Bayesian filtering User divides e-mail messages into spam or not-spam Assigns each word a probability of being spam  Corporate spam filter Works with the receiving e-mail server S ECURITY A WARENESS, 3 RD E DITION 29

30. D EFENSES T HROUGH A PPLICATIONS ( CONT ’ D.) Figure 3-16 Spam filter on SMTP server S ECURITY A WARENESS, 3 RD E DITION 30 Course Technology/Cengage Learning

31. D EFENSES T HROUGH A PPLICATIONS ( CONT ’ D.)  E-mail security settings  Configured through the e-mail client application Read messages using a reading pane Block external content Preview attachments Use an e-mail postmark S ECURITY A WARENESS, 3 RD E DITION 31

32. D EFENSES T HROUGH B ROWSER S ETTINGS  Browsers allow the user to customize security and privacy settings  IE Web browser defense categories:  Advanced security settings Do not save encrypted pages to disk Empty Temporary Internet Files folder when browser is closed Warn if changing between secure and not secure mode S ECURITY A WARENESS, 3 RD E DITION 32

33. D EFENSES T HROUGH B ROWSER S ETTINGS ( CONT ’ D.)  IE Web browser defense categories (cont’d.):  Security zones Set customized security for these zones Assign specific Web sites to a zone  Restricting cookies Use privacy levels in IE S ECURITY A WARENESS, 3 RD E DITION 33

34. D EFENSES T HROUGH B ROWSER S ETTINGS ( CONT ’ D.) Table 3-3 IE Web security zones S ECURITY A WARENESS, 3 RD E DITION 34 Course Technology/Cengage Learning

35. E- MAIL D EFENSES T HROUGH G OOD P RACTICES  Use common-sense procedures to protect against harmful e-mail  Never click an embedded hyperlink in an e-mail  Be aware that e-mail is a common method for infecting computers  Never automatically open an unexpected attachment  Use reading panes and preview attachments  Never answer an e-mail request for personal information S ECURITY A WARENESS, 3 RD E DITION 35

36. I NTERNET D EFENSE S UMMARY Table 3-4 Internet defense summary S ECURITY A WARENESS, 3 RD E DITION 36 Course Technology/Cengage Learning

37. S UMMARY  Internet composition  Web servers  Web browsers  Internet technologies  HTML  JavaScript  Java  ActiveX S ECURITY A WARENESS, 3 RD E DITION 37

38. S UMMARY ( CONT ’ D.)  Privacy risk  Cookies  Adware  Security risk  Mistyped Web address  Drive-by downloads  Email security  Spam  Attachments  Security applications S ECURITY A WARENESS, 3 RD E DITION 38