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Basic Network Security

Basic Network Security. Lesson 9. Objectives. Objectives. Network Security Considerations. Security policies should address: Security threats your organization has to combat What you can do to combat a security threat What you should do after a security violation has taken place.

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Basic Network Security

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  1. Basic Network Security Lesson 9

  2. Objectives

  3. Objectives

  4. Network Security Considerations • Security policies should address: • Security threats your organization has to combat • What you can do to combat a security threat • What you should do after a security violation has taken place

  5. Social Engineering • Tricking or manipulating a person into revealing important information

  6. Phishing • Using various means to trick people into revealing passwords, account numbers, social security numbers, and various other sensitive pieces of information • Common phishing scenarios • Foreign/unknown entities offering large transfers of money • E-mail requests to update banking information

  7. Phishing (Continued) • Countering threats • Verification of identifying picture • Verification of identifying question(s) • Development of other methods

  8. Stealing Passwords • Hackers find stealing passwords easier than breaking into a computer system • Many passwords are obvious phrases specific to users • Methods used to steal passwords • Phishing/asking user about family, pets, friends, and so on • Printed document hidden nearby computer

  9. Stealing Passwords (Continued) • Protecting passwords • Do not write password on paper • Create passwords that are easy to remember but difficult to crack • Check the strength of the password • Do not discuss password development techniques

  10. Identity Theft • The act of presenting yourself as someone you are not in order to steal in one way or another from the person you are presenting yourself to be • Common techniques • Stealing pin and/or bank account number and illegitimately representing self as owner • Elaborate phishing schemes

  11. Identity Theft (Continued) • Ways to protect information • Closely monitor financial activities • Pay third-party to monitor financial activities • Vigorously investigate and resolve any unusual transactions

  12. Dumpster Diving • The act of going through someone's garbage looking for personal information that can be used for identity theft • Information sources • Preapproved credit card applications • Company intellectual property

  13. Malicious Software • A broad category that includes any software that is used against a company or person • Intent behind the malicious software varies • A harmless prank • A deliberate attempt to cause extreme harm • To capture information from a victim; used for identity theft or targeted marketing

  14. Spyware • Software that is slipped onto a computer for the purpose of gaining private information about the target computer or how the computer is used • Can be slipped onto computers: • Via web browsers • By tricking people into installing it along with software they intended to install • Through e-mail

  15. Viruses • A type of malicious software that modifies the code of existing programs in an attempt to cause harm, reproduce itself, and/or to escape detection • A macro virus attaches to documents produced by common software applications • Anti-virus software greatly reduces occurrences • Software updates limit damage with built-in warnings

  16. Worms • Complete stand-alone programs that are smuggled onto a computer via some legitimate-seeming method and designed to carry out specific instructions that are detrimental to the computer or its user without the user's knowledge • Identification of worms • Ways smuggled in • Options to avoid

  17. Trojans • Malicious programs that actively masquerade as legitimate programs that belong on your computer • Designed to sneak onto a target system and run without interference • Used to create botnet systems

  18. Threats from Attackers • Social engineering • Denial of Service (DoS) and Distributed Denial of Service (DDoS) threats • Smurf attacks • Buffer overflow • Man-in-the-middle attacks • Packet sniffing • FTP bounce

  19. Social Engineering • Social engineering is single biggest threat from attacked network • Effective network protection gained through training • To identify and understand • To thwart attackers • To report observed or suspected activity

  20. Denial of Service • Denial of Service (DoS) and Distributed Denial of Service (DDoS) • DoS threats attempt to deny computer services in some way or another • DDoS attacks are launched from multiple locations against one or multiple targets all at once • Zombie network or botnet

  21. Forming a Zombie Network or Botnet

  22. Distributed Denial of Service (DDoS) Attack Using a Zombie Network or Botnet

  23. Smurf Attacks • A DoS attack in which the target server or network is flooded with Internet Control Message Protocol (ICMP) replies • Causes overloading of inbound network lines • Named after Smurf Trojan; similar to a Fraggle attack • No longer common

  24. Buffer Overflows • Buffer is a section of memory that has been set aside to use for actions related to a program • Buffer overflow (overrun) occurs when too much data in one section causes it to take space in adjacent memory locations • Overflow attacks vary with operating systems • Different attacks produce different results

  25. Man-in-the-Middle (MITM) Attacks • A person positions him- or herself between two other people and eavesdrops on them • MITM attacks also known as • Bucket-brigade, fire-brigade, monkey-in-the middle, session and TCP hijacking • Attacks used to intercept • HTTP and HTTPS communications • E-mail communications • Encryption key exchanges

  26. Mallory Perpetrating a Nan-in-the-Middle Attack Against Bob

  27. Packet Sniffing • The practice of capturing packets as they go by on the network and then opening them to see what is in them • Is used to • Spoof addresses • Determine network protocols • View contents of captured packets

  28. FTP Bounce • An exploit against the FTP protocol in which the attacker uses the PORT command to indirectly gain access to ports that are opened on the computer they are attempting to attack • Ports may be reassigned for another purpose • Attack minimizes scan being detected • nmap program can utilize FTP bounce

  29. Wireless Threats • War driving • Warchalking • WEP cracking • WPA cracking • Rogue access points • Evil twin

  30. War Driving • The practice of driving around in a car in an area or neighborhood looking for open wireless networks that can be used by the driver for their own purposes • Warchalking (variation on war driving) • Symbols placed on outdoor surfaces indicating availability and type of wireless access points

  31. Commonly Used Warchalking Symbols

  32. WEP Cracking • Breaking or decoding an encryption scheme used for passwords, wireless network access, or any other encrypted object • Easiest scheme to crack • Downloadable tools available

  33. WPA Cracking • Same as WEP cracking except encryption protocol targeted is WPA • Has both encryption and authentication functions • Downloadable tools available

  34. Rogue Access Points • Unauthorized access points added to a wireless network • May be malicious or benign • Often used in many man-in-the-middle attacks • Determining legitimate access points • Evil twin

  35. Rogue Access Point

  36. Countering Basic Security Threats

  37. Device Security • Physical security • Restricting local and remote access • Local access via LAN • Remote access via WAN • Secure versus unsecure access methods • What you know • What you have • What you are

  38. Device Security (Continued) • Protocols • Predefined standardized sets of rules used to communicate on a network • Secure protocols • Predefined standardized sets of rules used to secure communications on a network • Security strives for: • Confidentiality, integrity, authentication

  39. Device Security (Continued) • Examples of secure protocols • Secure Shell (SSH) • Hypertext Transfer Protocol Secure (HTTPS) • Simple Network Management Protocol Version 3 (SNMPV3) • Secure File Transfer Protocol (SFTP) • Secure Copy Protocol (SCP)

  40. Device Security (Continued) • Examples of unsecure protocols • Telnet • Hypertext Transfer Protocol (HTTP) • File Transfer Protocol (FTP) • Remote Shell (RSH) • Fibre Channel Protocol (FCP) • Simple Network Management Protocol Versions 1 and 2 (SNMPV1/2)

  41. Passwords • Are used to verify that the person attempting to access a system is the person they claim to be • Should be complex enough to not be easily guessed • Should be renewed and changed periodically • Should not use the same password for everything

  42. Encryption • The process by which a mathematical algorithm is run on a set of data to make it unreadable to someone who does not know the mathematical algorithm used to encode it • Private key encryption • Public key encryption • Network security through confidentiality and integrity

  43. Private Key Encryption

  44. Public Key Encryption

  45. Certificates • Are certifications that a public key is valid • Also called public key certificates or digital certificates • Identify owner of public key (holder) • Contain actual public key • Identify issuer of public key and digital certificate (certificate authority) • Public Key Infrastructure (PKI) • Temporal Key Integrity Protocol (TKIP)

  46. Authentication • The process of verifying a user or computer to be who or what they claim to be • Includes: • Multi-factor authentication • Two-factor authentication • Single sign-on • More

  47. Public Key Infrastructure (PKI) • A set of people, policies, software, and equipment needed to handle digital certificates for various applications • End user is person that wishes to use PKI • Registration authority (RA) verifies that a specific public key belongs to a specific end user • Certificate authority (CA) issues digital certificate to end user, sends information about certificate to a validation authority (VA) • VA verifies certificate when requested by e-commerce site or other online service

  48. How PKI Works

  49. Kerberos • An authentication protocol that authenticates clients over an unsecured network, most commonly LANs • Most commonly used by Windows-based client/server networks • Composed of an authentication service (AS), a ticket granting service (TGS), and a network services (NS)

  50. How Kerberos Works in a Windows Environment

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