Chapter 3 Ensuring Internet Security


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Chapter 3 Ensuring Internet Security

  1. 1. Chapter 3 Ensuring Internet Security
  2. 2. Learning Objectives <ul><li>Differentiate between the different types of malware. </li></ul><ul><li>Explain how antivirus programs work. </li></ul><ul><li>Examine how a firewall works. </li></ul><ul><li>Explain the role service patches and updates play in maintaining computer security. </li></ul><ul><li>Explain phishing and 419 scams. </li></ul><ul><li>Compare and contrast DoS, DDoS, and brute force attacks. </li></ul>
  3. 3. Learning Objectives <ul><li>Change Internet Explorer security settings. </li></ul><ul><li>Summarize how encryption works. </li></ul><ul><li>Explain the difference between adware and spyware and discuss the implications of each. </li></ul><ul><li>Describe how cookies work. </li></ul><ul><li>Describe methods that can be used to block spam. </li></ul><ul><li>Explain the procedures designed to avoid adware and spyware. </li></ul>
  4. 4. Chapter Focus <ul><li>Malware </li></ul><ul><li>Malware Countermeasures </li></ul><ul><li>Cyber Crime </li></ul><ul><li>Cyber Crime Countermeasures </li></ul><ul><li>Threats to Privacy </li></ul><ul><li>Privacy Countermeasures </li></ul>
  5. 5. Malware <ul><li>Any program or computer code deliberately designed to harm any portion of a computer system </li></ul>Microsoft Decision Tree
  6. 6. Malware <ul><li>Viruses </li></ul><ul><ul><li>A self-replicating form of malware </li></ul></ul><ul><ul><li>Spread from computer to computer using another file or program as a host </li></ul></ul><ul><ul><li>When virus is executed, its payload is released — the malicious action is performed </li></ul></ul><ul><ul><ul><li>Data corruption or deletion </li></ul></ul></ul><ul><ul><ul><li>Information theft </li></ul></ul></ul><ul><ul><ul><li>Consumed system resources </li></ul></ul></ul>
  7. 7. Malware <ul><li>Worms </li></ul><ul><ul><li>Spreads through network connections without the need for a host program </li></ul></ul><ul><ul><li>Computer Emergency Response Team (CERT Coordination Center) </li></ul></ul><ul><ul><ul><li>Coordinates efforts to deal with threats to computer security and to build security issue awareness among Internet users </li></ul></ul></ul><ul><ul><ul><li> is a valuable source of information on the latest computer security threats </li></ul></ul></ul>
  8. 8. Malware CERT/CC Home Page
  9. 9. Malware <ul><li>Trojan Horses </li></ul><ul><ul><li>Disguises itself as a harmless or legitimate program to persuade people to download and run it </li></ul></ul><ul><ul><li>Does not need to self-replicate like a virus or worm </li></ul></ul><ul><ul><li>When executed, the file is able to unleash its payload </li></ul></ul>
  10. 10. Malware Review <ul><li>What are the key distinguishing characteristics of viruses, worms, and Trojan horses? </li></ul><ul><li>What is a backdoor payload? </li></ul><ul><li>What is a malware payload? </li></ul>
  11. 11. Malware Countermeasures <ul><li>Antivirus Programs </li></ul><ul><ul><li>Scans computers or computer systems to detect any malware that may be present </li></ul></ul><ul><ul><li>Most offer proactive software for prevention of malware </li></ul></ul><ul><ul><li>Very popular antivirus programs </li></ul></ul><ul><ul><ul><li>Norton Antivirus </li></ul></ul></ul><ul><ul><ul><li>PC-Cillin </li></ul></ul></ul><ul><ul><ul><li>McAfee VirusScan </li></ul></ul></ul><ul><ul><ul><li>Antivirus Program Download Page </li></ul></ul></ul>
  12. 12. Malware Countermeasures <ul><li>Antivirus Programs </li></ul><ul><ul><li>3 options when an infected file is found </li></ul></ul><ul><ul><ul><li>Clean the file, delete the file, quarantine the file </li></ul></ul></ul>Online Antivirus Scanning
  13. 13. Malware Countermeasures <ul><ul><li>Windows Vista includes a System Restore function </li></ul></ul><ul><ul><ul><li>Allows user to revert the computer settings from a previous point in time </li></ul></ul></ul><ul><ul><ul><li>Can allow viruses to remain in backup files where they cannot be cleaned or deleted by antivirus programs </li></ul></ul></ul>
  14. 14. Malware Countermeasures Disabling Windows Vista System Restore Function
  15. 15. Malware Countermeasures <ul><li>Signature Scanning </li></ul><ul><ul><li>Virus Signature </li></ul></ul><ul><ul><ul><li>A string of binary code unique to a particular virus </li></ul></ul></ul><ul><ul><li>Drawbacks to signature scanning </li></ul></ul><ul><ul><ul><li>Polymorphic viruses change with each replication </li></ul></ul></ul><ul><ul><ul><li>Ineffective against new viruses for which signature updates do not yet exist </li></ul></ul></ul><ul><ul><ul><li>Signature scanning is reactive rather than preventive </li></ul></ul></ul>
  16. 16. Malware Countermeasures <ul><li>Heuristic Scanning </li></ul><ul><ul><li>Looks for general malware characteristics </li></ul></ul><ul><ul><li>Relies on previous experience or knowledge </li></ul></ul><ul><ul><li>Can produce false positives and negatives </li></ul></ul><ul><ul><li>Requires periodic updates to ensure that the catalog of suspicious characteristics is up-to-date </li></ul></ul>
  17. 17. Malware Countermeasures <ul><li>Behavior Blocking </li></ul><ul><ul><li>Looks for typical malware behaviors </li></ul></ul><ul><ul><ul><li>Attempts to change computer settings </li></ul></ul></ul><ul><ul><ul><li>Opening and/or alteration of files </li></ul></ul></ul><ul><ul><ul><li>Network communications initiation </li></ul></ul></ul><ul><ul><ul><li>Attempts to open computer ports </li></ul></ul></ul>
  18. 18. Malware Countermeasures <ul><li>Firewalls </li></ul><ul><ul><li>Hardware or software barrier located between the Internet and a computer or computer network </li></ul></ul><ul><ul><li>Filters data arriving through the Internet </li></ul></ul><ul><ul><li>Use a proxy server to handle page and data requests to add another level of threat protection </li></ul></ul>
  19. 19. Malware Countermeasures <ul><li>Firewalls </li></ul><ul><ul><li>Microsoft Vista features a software firewall that can be enabled by users </li></ul></ul>
  20. 20. Malware Countermeasures <ul><li>Service Patches and Updates </li></ul><ul><ul><li>Released by Microsoft for Windows operating system versions </li></ul></ul><ul><ul><li>To repair system vulnerabilities when discovered </li></ul></ul><ul><ul><li>The default Windows Vista configuration periodically checks for new security patches or updates, then automatically downloads and installs them </li></ul></ul>
  21. 21. Malware Countermeasures <ul><li>Password Protection </li></ul><ul><ul><li>To ensure that unauthorized parties do not obtain access to your confidential data </li></ul></ul><ul><ul><li>Especially important if you share your computer with others or if you are on a network </li></ul></ul>
  22. 22. Malware Countermeasures Review <ul><li>What can be done to protect your computer against malware? </li></ul><ul><li>What are the different methods that antivirus programs use to detect malware? </li></ul><ul><li>What does a firewall do? </li></ul>
  23. 23. Cyber Crime <ul><li>Refers to crimes committed using the Internet </li></ul><ul><li>Several techniques of cyber crime: </li></ul><ul><ul><li>Phishing </li></ul></ul><ul><ul><li>419 Scams </li></ul></ul><ul><ul><li>Denial-of-Service (DoS) Attacks </li></ul></ul><ul><ul><li>Brute Force Attacks </li></ul></ul>
  24. 24. Cyber Crime <ul><li>Phishing </li></ul><ul><ul><li>Online scammer sends a user an e-mail that appears to be from a legitimate and well-known company to try to trick the user into sending confidential information </li></ul></ul><ul><ul><li>Current phishing attacks are estimated to have a 3% success rate </li></ul></ul>
  25. 25. Cyber Crime Spoofed eBay E-mail
  26. 26. Cyber Crime <ul><li>419 Scams </li></ul><ul><ul><li>Advanced fee fraud </li></ul></ul><ul><ul><li>Majority of crime originates in Nigeria </li></ul></ul><ul><ul><li>Victim receives an e-mail asking to front some money to help smuggle a large amount of money out of the country in exchange for a percentage of the smuggled money </li></ul></ul>
  27. 27. Cyber Crime 419 Scam E-mail
  28. 28. Cyber Crime <ul><li>Denial-of-Service (DoS) Attacks </li></ul><ul><ul><li>Paralyze computer networks by bombarding them with traffic in the form of packets of useless information </li></ul></ul><ul><ul><li>Goal is to deny services to opposition based on economic or political reasons, or just for fun </li></ul></ul><ul><ul><li>Past victims </li></ul></ul><ul><ul><ul><li>Microsoft, U.S. Government, Yahoo, Amazon, </li></ul></ul></ul>
  29. 29. Cyber Crime <ul><li>Brute force attacks </li></ul><ul><ul><li>Aims to overcome a password-protected computer or network by systematically trying different combinations of letters and numbers </li></ul></ul><ul><ul><li>Users should use effective passwords </li></ul></ul><ul><ul><ul><li>Not simple or easily deduced words or number combinations </li></ul></ul></ul>
  30. 30. Cyber Crime Review <ul><li>How would you define cyber crime? </li></ul><ul><li>What are some of the different types of cyber crime? </li></ul><ul><li>What is spoofing, and what role does it play in cyber crime? </li></ul>
  31. 31. Cyber Crime Countermeasures <ul><li>Additional tools are needed to protect against cyber crime </li></ul><ul><ul><li>Tailored security settings in Internet Explorer </li></ul></ul><ul><ul><li>Encryption to authenticate and protect communications including confidential transactions </li></ul></ul>
  32. 32. Cyber Crime Countermeasures <ul><li>Internet Explorer Security Settings </li></ul><ul><ul><li>Enables users to assign Web sites to different Web content security zones depending on how trusted the sites are </li></ul></ul><ul><ul><ul><li>Low </li></ul></ul></ul><ul><ul><ul><li>Medium-Low </li></ul></ul></ul><ul><ul><ul><li>Medium (recommended) </li></ul></ul></ul><ul><ul><ul><li>High </li></ul></ul></ul><ul><ul><li>The higher the security level, the more restrictive it is </li></ul></ul>
  33. 33. Cyber Crime Countermeasures Internet Explorer Security Settings level slider
  34. 34. Cyber Crime Countermeasures File Download Warning Message
  35. 35. Cyber Crime Countermeasures <ul><li>Encryption and Authentication </li></ul><ul><ul><li>Encryption </li></ul></ul><ul><ul><ul><li>Refers to the process of using an algorithm to scramble text or data into an unreadable format that cannot be unscrambled without the use of a key </li></ul></ul></ul><ul><ul><li>Authentication </li></ul></ul><ul><ul><ul><li>Refers to the process of verification </li></ul></ul></ul>
  36. 36. Cyber Crime Countermeasures <ul><li>Symmetric Encryption/Asymmetric Encryption </li></ul><ul><ul><li>Symmetric encryption </li></ul></ul><ul><ul><ul><li>Message sender and recipient both use the same private key to encrypt and decrypt communication </li></ul></ul></ul><ul><ul><li>Asymmetric encryption </li></ul></ul><ul><ul><ul><li>Uses paired private and public keys to encrypt and decrypt data </li></ul></ul></ul>
  37. 37. Cyber Crime Countermeasures
  38. 38. Cyber Crime Countermeasures <ul><li>Digital Certificates </li></ul><ul><ul><li>Provides a means of verifying that a public key belongs to the person who claims to own it </li></ul></ul><ul><ul><li>Personal Certificate contains at least: </li></ul></ul><ul><ul><ul><li>Public key owner’s name </li></ul></ul></ul><ul><ul><ul><li>Expiration date </li></ul></ul></ul><ul><ul><ul><li>Name of the Certification Authority (CA) that issued the certificate </li></ul></ul></ul><ul><ul><ul><li>Serial number </li></ul></ul></ul><ul><ul><ul><li>Digital signature for the CA </li></ul></ul></ul>
  39. 39. Cyber Crime Countermeasures Digital Certificate public key owner’s name CA that issued the certificate expiration date
  40. 40. Cyber Crime Countermeasures Digital Certification Online Application
  41. 41. Cyber Crime Countermeasures <ul><li>Digital Signatures </li></ul><ul><ul><li>Uses encryption to help a message recipient confirm that: </li></ul></ul><ul><ul><ul><li>A digitally signed message originates from the person claiming to have sent it </li></ul></ul></ul><ul><ul><ul><li>The message contents have not been altered </li></ul></ul></ul><ul><ul><li>Hashing </li></ul></ul><ul><ul><ul><li>Contents of a message are reduced to a message digest </li></ul></ul></ul>
  42. 42. Cyber Crime Countermeasures
  43. 43. Cyber Crime Countermeasures <ul><li>Secure Sockets Layer (SSL) Protocol </li></ul><ul><ul><li>Ensures the security of confidential information such as that for financial transactions conducted over the Internet </li></ul></ul><ul><ul><li>URL will begin with https during a secure connection </li></ul></ul><ul><ul><li>Internet Explorer displays a closed padlock icon at right end of the browser window status bar </li></ul></ul>
  44. 44. Cyber Crime Countermeasures https protocol padlock icon
  45. 45. Cyber Crime Countermeasures <ul><li>Biometric Authentication </li></ul><ul><ul><li>Uses biological features to verify identity </li></ul></ul><ul><ul><ul><li>Fingerprints </li></ul></ul></ul><ul><ul><ul><li>Speech </li></ul></ul></ul><ul><ul><ul><li>Iris patterns </li></ul></ul></ul><ul><ul><li>Current fingerprint scanners are not foolproof </li></ul></ul>
  46. 46. Cyber Crime Countermeasures Review <ul><li>How can using Internet Explorer security zones protect a computer or network? </li></ul><ul><li>How does asymmetric encryption work? </li></ul><ul><li>What is the process of creating a digital signature? </li></ul>
  47. 47. Threats to Privacy <ul><li>Spam </li></ul><ul><li>Adware/Spyware </li></ul><ul><li>Cookies </li></ul><ul><li>Inappropriate Content </li></ul>
  48. 48. Threats to Privacy <ul><li>Spam </li></ul><ul><ul><li>Online equivalent of the junk mail delivered by the U.S. Postal Service </li></ul></ul><ul><ul><li>Spammers find e-mail addresses by: </li></ul></ul><ul><ul><ul><li>Combining through newsgroups and chat rooms </li></ul></ul></ul><ul><ul><ul><li>Checking Web sites </li></ul></ul></ul><ul><ul><ul><li>Using software that gathers name lists from ISP directories </li></ul></ul></ul><ul><ul><ul><li>Using pop-up ads that say user has won a prize </li></ul></ul></ul>
  49. 49. Threats to Privacy <ul><li>Adware/Spyware </li></ul><ul><ul><li>Adware – Advertising Supported Software </li></ul></ul><ul><ul><ul><li>Often included in shareware and freeware software </li></ul></ul></ul><ul><ul><ul><li>Fee paid by adware advertisers helps pay for shareware and freeware costs </li></ul></ul></ul><ul><ul><li>Spyware </li></ul></ul><ul><ul><ul><li>Used to gather user information without their knowledge </li></ul></ul></ul><ul><ul><ul><li>Usually promise not to identify users </li></ul></ul></ul><ul><ul><ul><ul><li>Impossible to verify </li></ul></ul></ul></ul>
  50. 50. Threats to Privacy <ul><li>Cookies </li></ul><ul><ul><li>Very small text files placed on a computer so Web site servers can recognize previous visitors to customize viewing experience </li></ul></ul><ul><ul><li>Not a program </li></ul></ul><ul><ul><li>Temporary or session cookies </li></ul></ul><ul><ul><ul><li>Deleted when browser is closed </li></ul></ul></ul><ul><ul><li>Persistent cookies </li></ul></ul><ul><ul><ul><li>Remain even after browser is closed </li></ul></ul></ul>
  51. 51. Threats to Privacy CNN Weather Information Preference Cookie cookie text
  52. 52. Threats to Privacy Review <ul><li>What is spam, and how do spammers find e-mail addresses to send spam to? </li></ul><ul><li>What is the difference between adware and spyware? </li></ul><ul><li>How do cookies work? </li></ul>
  53. 53. Privacy Countermeasures <ul><li>Spam Blocking Methods </li></ul><ul><ul><li>A lot of spam can be avoided by being careful </li></ul></ul><ul><ul><ul><li>Never buying a product advertised in a spam message </li></ul></ul></ul><ul><ul><ul><li>Never reply to a spam message </li></ul></ul></ul><ul><ul><ul><li>Do not forward chain letters or mass mailings </li></ul></ul></ul><ul><ul><ul><li>Be careful when subscribing to anything, and check for a privacy statement </li></ul></ul></ul><ul><ul><ul><li>Avoid Web sites without privacy policies, and look for check boxes placing you on mailing lists or making your e-mail addresses available to advertisers </li></ul></ul></ul>
  54. 54. Privacy Countermeasures
  55. 55. Privacy Countermeasures <ul><ul><ul><li>Do not post your e-mail address in Internet e-mail directories </li></ul></ul></ul><ul><ul><ul><li>Set up a free mail service e-mail address, such as Hotmail or Yahoo, and use it for Internet transactions to protect your normal e-mail address </li></ul></ul></ul><ul><ul><ul><li>Disable automatic image downloading in HTML e-mail </li></ul></ul></ul><ul><ul><li>Install spam filtering software </li></ul></ul><ul><ul><ul><li>Must be updated periodically to maintain effectiveness </li></ul></ul></ul>
  56. 56. Privacy Countermeasures <ul><li>Spyware/Adware Avoidance </li></ul><ul><ul><li>Modify online behavior such as: </li></ul></ul><ul><ul><ul><li>Being wary when downloading and installing freeware or shareware </li></ul></ul></ul><ul><ul><ul><li>Closing any unexpected or unfamiliar dialog boxes using the close button (X) </li></ul></ul></ul><ul><ul><ul><li>Change your browser security settings to prevent the unauthorized download and installation of ActiveX controls </li></ul></ul></ul><ul><ul><ul><li>Delete spam without opening it </li></ul></ul></ul>
  57. 57. Privacy Countermeasures <ul><ul><ul><li>Never click on links inside pop-up windows, even if the link says Close. Use the Close button on the title bar to close the window </li></ul></ul></ul><ul><ul><ul><li>Activate or install browser anti-pop-up window features </li></ul></ul></ul><ul><ul><li>Install software developed to detect, remove, and block adware and spyware </li></ul></ul><ul><ul><ul><li>Microsoft offers a free beta (trial) version of its AntiSpyware program, Windows Defender </li></ul></ul></ul><ul><ul><ul><li>Internet Explorer 7 includes a built-in pop-up window blocker that is activated by default </li></ul></ul></ul>
  58. 58. Privacy Countermeasures <ul><ul><li>Proposed legislation would criminalize the installation of spyware without the express approval of computer owners </li></ul></ul>
  59. 59. Privacy Countermeasures Spyware Doctor Adware and Spyware Removal Program
  60. 60. Privacy Countermeasures <ul><li>Cookie Blocking </li></ul><ul><ul><li>Internet Explorer 7 browser’s custom privacy settings allow users to enable different levels of cookie management </li></ul></ul><ul><ul><ul><li>Can range from accepting all cookies to blocking all cookies </li></ul></ul></ul><ul><ul><ul><li>Blocking all cookies can disable some functionality and user may not be able to have a customized experience </li></ul></ul></ul>
  61. 61. Privacy Countermeasures <ul><ul><ul><li>Can create custom settings for a particular site </li></ul></ul></ul><ul><ul><ul><li>Changing privacy settings does not affect cookies that are already stored on the system; user should delete existing cookies to ensure new settings affect all cookies </li></ul></ul></ul>
  62. 62. Privacy Countermeasures Internet Explorer Custom Privacy Settings
  63. 63. Privacy Countermeasures <ul><li>Inappropriate Content </li></ul><ul><ul><li>No single standard </li></ul></ul><ul><ul><li>Nature of Internet makes it difficult for people to avoid seeing material that they feel is inappropriate </li></ul></ul><ul><ul><li>Impossible for Web site and chat room operators to verify the age of people viewing their material </li></ul></ul>
  64. 64. Privacy Countermeasures <ul><li>Parental Control Software </li></ul><ul><ul><li>Enables parents to control the Internet content their children can access </li></ul></ul><ul><ul><li>Parents can also control activities </li></ul></ul><ul><ul><ul><li>File downloading or sharing </li></ul></ul></ul><ul><ul><ul><li>Instant messaging </li></ul></ul></ul><ul><ul><ul><li>Games </li></ul></ul></ul><ul><ul><li>Parents can set time limits and access an Internet log </li></ul></ul>
  65. 65. Privacy Countermeasures <ul><li>Windows Vista comes with built-in parental controls </li></ul><ul><ul><li>Allow access to only specified Web sites </li></ul></ul><ul><ul><li>Block file downloads </li></ul></ul><ul><ul><li>Control times when specific accounts can log on to Windows </li></ul></ul><ul><ul><li>Disallow the account access to Web sites except for specific sites </li></ul></ul>
  66. 66. Privacy Countermeasures
  67. 67. Privacy Countermeasures Review <ul><li>What are the different ways that Internet Explorer can be configured to block cookies? </li></ul><ul><li>What measures can Internet users undertake to reduce the amount of spam they receive? </li></ul><ul><li>What can Internet users do to avoid unwanted adware and spyware programs? </li></ul>