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Host and Information Security

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  1. Host and Data Security Chapter 7

  2. Copyright Pearson Prentice-Hall 2010; edited by Yue Zhang, CSU-Northridge Inevitably, some attacks will get through network safeguards and reach individual hosts Host hardening is a series of actions taken to make hosts more difficult to take over Chapter 7 focuses on host operating system and data protection Chapter 8 focuses on application protection Orientation 2

  3. Copyright Pearson Prentice-Hall 2010; edited by Yue Zhang, CSU-Northridge The Problem Some attacks inevitably reach host computers So servers and other hosts must be hardened— a complex process that requires a diverse set of protections to be implemented on each host 7-1: Threats to Hosts 3

  4. Copyright Pearson Prentice-Hall 2010; edited by Yue Zhang, CSU-Northridge What Is a Host? Anything with an IP address is a host (because it can be attacked) Servers Clients (including mobile telephones) Routers (including home access routers) and sometimes switches Firewalls 7-1: Threats to Hosts 4

  5. Copyright Pearson Prentice-Hall 2010; edited by Yue Zhang, CSU-Northridge Backup Backup Backup Restrict physical access to hosts (see Chapter 5) Install the operating system with secure configuration options Change all default passwords, etc. 7-2: Elements of Host Hardening 5

  6. Copyright Pearson Prentice-Hall 2010; edited by Yue Zhang, CSU-Northridge Minimize the applications that run on the host Harden all remaining applications on the host (see Chapter 8) Download and install patches for operating vulnerabilities Manage users and groups securely Add, change, delete Manage access permissions for users and groups securely 7-2: Elements of Host Hardening 6

  7. Copyright Pearson Prentice-Hall 2010; edited by Yue Zhang, CSU-Northridge Encrypt data if appropriate Add a host firewall Read operating system log files regularly for suspicious activities Run vulnerability tests frequently 7-2: Elements of Host Hardening 7

  8. Copyright Pearson Prentice-Hall 2010; edited by Yue Zhang, CSU-Northridge Security Baselines Guide the Hardening Effort Specifications for how hardening should be done Needed because it is easy to forget a step Different baselines for different operating systems and versions Different baselines for servers with different functions (webservers, mail servers, etc.) Used by systems administrators (server administrators) Usually do not manage the network 7-3: Security Baselines and Systems Administrators 8

  9. Copyright Pearson Prentice-Hall 2010; edited by Yue Zhang, CSU-Northridge Security Baselines Guide the Hardening Effort Disk Images Can also create a well-tested secure implementation for each operating system versions and server function Save as a disk image Load the new disk image on new servers Add for next slide: focus on servers – often targets of attacks; OS – frequent attack vectors for server hackers 7-3: Security Baselines and Systems Administrators 9

  10. Copyright Pearson Prentice-Hall 2010; edited by Yue Zhang, CSU-Northridge Windows Server The Microsoft Windows Server operating system Windows NT, 2003, and 2008 Windows Server Security Intelligently minimize the number of running programs and utilities by asking questions during installation Simple (and usually automatic) to get updates Still many patches to apply, but this is true of other operating systems 7-4: Windows Server Operating Systems 10

  11. Copyright Pearson Prentice-Hall 2010; edited by Yue Zhang, CSU-Northridge 7-5: Windows 2008 Server User Interface Looks like client versions of Windows Ease of learning and use Choose Administrative Tools for most programs Tools are called Microsoft Management Consoles (MMCs) 11 Copyright Pearson Prentice-Hall 2009

  12. Copyright Pearson Prentice-Hall 2010; edited by Yue Zhang, CSU-Northridge 7-6: Computer Management Microsoft Management Console (MMC) MMCs have standard user interfaces 12

  13. Copyright Pearson Prentice-Hall 2010; edited by Yue Zhang, CSU-Northridge Many Versions of UNIX There are many commercial versions of UNIX for large servers Compatible in the kernel (core part) of the operating system Can generally run the same applications But may run many different management utilities, making cross-learning difficult 7-7: UNIX Operating Systems 13

  14. Copyright Pearson Prentice-Hall 2010; edited by Yue Zhang, CSU-Northridge Many Versions of UNIX LINUX is a version of UNIX created for PCs Many different LINUX distributions Distributions include the LINUX kernel plus application and programs, usually from the GNU project Each distribution and version needs a different baseline to guide hardening 7-7: UNIX Operating Systems 14

  15. Copyright Pearson Prentice-Hall 2010; edited by Yue Zhang, CSU-Northridge Many Versions of UNIX LINUX is a version of UNIX created for PCs Free or inexpensive to buy But may take more labor to administer Has moved beyond PC, to use on servers and some desktops 7-7: UNIX Operating Systems 15

  16. Copyright Pearson Prentice-Hall 2010; edited by Yue Zhang, CSU-Northridge User Can Select the User Interface Multiple user interfaces are available (unlike Windows) Graphical user interfaces (GUIs) Command line interfaces (CLIs) At prompts, users type commands Unix CLIs are called shells (Bourne, BASH, etc.) 7-7: UNIX Operating Systems >ls -1 … 16

  17. Copyright Pearson Prentice-Hall 2010; edited by Yue Zhang, CSU-Northridge Vulnerabilities Security weaknesses that open a program to attack An exploit takes advantage of a vulnerability Vendors develop fixes Zero-day exploits: exploits that occur before fixes are released Exploits often follow the vendor release of fixes within days or even hours Companies must apply fixes quickly 7-8: Vulnerabilities and Exploits 17

  18. Copyright Pearson Prentice-Hall 2010; edited by Yue Zhang, CSU-Northridge Fixes Work-arounds Manual actions to be taken Labor-intensive so expensive and error-prone Patches: Small programs that fix vulnerabilities Usually easy to download and install Service packs (groups of fixes in Windows) Version upgrades 7-8: Vulnerabilities and Exploits 18

  19. Copyright Pearson Prentice-Hall 2010; edited by Yue Zhang, CSU-Northridge Problems with Patching Must find operating system patches Windows Server does this automatically LINUX versions often use rpm … Companies get overwhelmed by number of patches Use many programs; vendors release many patches per product Especially a problem for a firm’s many application programs P.313 - # patches 7-9: Applying Patching 19

  20. Copyright Pearson Prentice-Hall 2010; edited by Yue Zhang, CSU-Northridge Problems with Patching Cost of patch installation Each patch takes some time and labor costs Usually lack the resources to apply all Prioritization Prioritize patches by criticality May not apply all patches, if risk analysis does not justify them 7-9: Applying Patching 20

  21. Copyright Pearson Prentice-Hall 2010; edited by Yue Zhang, CSU-Northridge Problems with Patching Risks of patch installation Reduced functionality Freeze machines, do other damage—sometimes with no uninstall possible Should test on a test system before deployment on servers 7-9: Applying Patching 21

  22. Copyright Pearson Prentice-Hall 2010; edited by Yue Zhang, CSU-Northridge Accounts Every user must have an account Groups Individual accounts can be consolidated into groups Can assign security measures to groups Inherited by each group’s individual members Reduces cost compared to assigning to individuals Reduces errors 7-10: Managing Users and Groups ABC XYZ 22

  23. Copyright Pearson Prentice-Hall 2010; edited by Yue Zhang, CSU-Northridge 7-11: Users and Groups in Windows 2. Select a particular user 1. Select Users or Groups Right-click. Select properties. Change selected properties. 23

  24. Copyright Pearson Prentice-Hall 2010; edited by Yue Zhang, CSU-Northridge 7-13: Windows User Account Properties Administrator Account selected 24

  25. Copyright Pearson Prentice-Hall 2010; edited by Yue Zhang, CSU-Northridge Super User Account Every operating system has a super user account The owner of this account can do anything Called Administrator in Windows Called root in UNIX Hacking Root Goal is to take over the super user account Will then “own the box” Generically called hacking root 7-12: The Super User Account 25

  26. Copyright Pearson Prentice-Hall 2010; edited by Yue Zhang, CSU-Northridge Appropriate Use of a Super User Account Log in as an ordinary user Switch to super user only when needed In Windows, the command is RunAs In UNIX, the command is su (switch user) Quickly revert to ordinary account when super user privileges are no longer needed 7-12: The Super User Account 26

  27. Copyright Pearson Prentice-Hall 2010; edited by Yue Zhang, CSU-Northridge Permissions Specify what the user or group can do to files, directories, and subdirectories Assigning Permissions in Windows (Fig. 7-15) Right click on file or directory Select Properties, then Security tab Select a user or group Select the 6 standard permissions (permit or deny) For more fine-grained control, 13 special permissions 7-14: Managing Permissions in Windows 27

  28. Copyright Pearson Prentice-Hall 2010; edited by Yue Zhang, CSU-Northridge 7-15: Assigning Permissions in Windows 28

  29. Copyright Pearson Prentice-Hall 2010; edited by Yue Zhang, CSU-Northridge Inheritance If the Allow inheritable permissions from parent to propagate to this object box is checked in the security tab, the directory receives the permissions of the parent directory. This box is checked by default, so inheritance from the parent is the default 7-16: The Inheritance of Permission 29

  30. Copyright Pearson Prentice-Hall 2010; edited by Yue Zhang, CSU-Northridge Inheritance Total permissions include Inherited permissions (if any) Plus the Allow permissions checked in the Security tab Minus the Deny permissions checked in the Security tab The result is the permissions level for a directory or file 7-16: The Inheritance of Permission XYZ XYZ 30

  31. Copyright Pearson Prentice-Hall 2010; edited by Yue Zhang, CSU-Northridge Directory Organization Proper directory organization can make inheritance a great tool for avoiding labor Example: Suppose the all logged-in user group is given read and execute permissions in the public programs directory Then all programs in this directory and its subdirectories will have read and execute permissions for everyone who is logged in There is no need to assign permissions to subdirectories and their files 7-16: The Inheritance of Permission 31

  32. Copyright Pearson Prentice-Hall 2010; edited by Yue Zhang, CSU-Northridge 7-17: Assigning Permissions in Windows and UNIX 32

  33. Copyright Pearson Prentice-Hall 2010; edited by Yue Zhang, CSU-Northridge Mistakes Will Be Made in Hardening So do vulnerability testing Run Vulnerability Testing Software on Another Computer Run the software against the hosts to be tested Interpret the reports about problems found on the server This requires extensive security expertise Fix them 7-18: Vulnerability Testing 33

  34. Copyright Pearson Prentice-Hall 2010; edited by Yue Zhang, CSU-Northridge Get Permission for Vulnerability Testing Looks like an attack Must get prior written agreement Vulnerability testing plan An exact list of testing activities Approval in writing to cover the tester Supervisor must agree, in writing, to hold the tester blameless if there is damage Tester must not diverge from the plan 7-18: Vulnerability Testing 34

  35. Copyright Pearson Prentice-Hall 2010; edited by Yue Zhang, CSU-Northridge Client PC Security Baselines For each version of each operating system Within an operating system, for different types of computers (desktop versus notebook, on-site versus external, high-risk versus normal risk, and so forth) Automatic Updates for Security Patches Completely automatic updating is the only reasonable policy 7-19: Windows Client PC Security 35

  36. Copyright Pearson Prentice-Hall 2010; edited by Yue Zhang, CSU-Northridge Antivirus and Antispyware Protection Important to know the status of antivirus protection Users turn off or turn off automatic updating for virus signatures Users do not pay the annual subscription and so get no more updates Windows Firewall Stateful inspection firewall Accessed through the Security Center (or Action Center) 7-19: Windows Client PC Security 36

  37. Copyright Pearson Prentice-Hall 2010; edited by Yue Zhang, CSU-Northridge Figure 7-20: Windows Security Center Security Center Check for updates Check this computer’s security status Turn automatic updating on or off Check firewall status Require a password when the computer wakes 37

  38. Copyright Pearson Prentice-Hall 2010; edited by Yue Zhang, CSU-Northridge Figure 7-20: Windows Security Center Windows Firewall Turn Windows Firewall on or off Allow a program through Windows Firewall Windows Update Turn automatic updating on or off Check for updates View installed updates 38

  39. Copyright Pearson Prentice-Hall 2010; edited by Yue Zhang, CSU-Northridge Figure 7-20: Windows Security Center Internet Options Change security centers Delete browsing history and cookies Manage browser add-ins Windows Defender Spyware scanner 39

  40. Copyright Pearson Prentice-Hall 2010; edited by Yue Zhang, CSU-Northridge Threats Loss or theft Loss of capital investment Loss of data that was not backed up Loss of trade secrets Loss of private information, leading to lawsuits 7-21: Protecting Notebook Computers 40

  41. Copyright Pearson Prentice-Hall 2010; edited by Yue Zhang, CSU-Northridge Backup Before taking the notebook out Frequently during use outside the firm Use a Strong Password If attackers bypass the operating system password, they get open access to encrypted data The loss of login passwords is a major concern 7-21: Protecting Notebook Computers 41

  42. Copyright Pearson Prentice-Hall 2010; edited by Yue Zhang, CSU-Northridge Policies for Sensitive Data Four main policies: Limit what sensitive data can be stored on all mobile devices Require data encryption for all data Protect the notebook with a strong login password Audit for the previous two policies Apply policies to all mobile data on disk drives, USB RAM drives, MP3 players that store data, and even mobile phones that can store data 7-21: Protecting Notebook Computers 42

  43. Copyright Pearson Prentice-Hall 2010; edited by Yue Zhang, CSU-Northridge Other Measures Teach users loss and theft protection techniques Use notebook recovery software Contacts the recovery company the next time the computer connects to the Internet The recover company contacts local police to recover the software 7-21: Protecting Notebook Computers 43

  44. Copyright Pearson Prentice-Hall 2010; edited by Yue Zhang, CSU-Northridge Importance Ordinary users lack the knowledge to manage security on their PCs They sometimes knowingly violate security policies Also, centralized management often can reduce costs through automation 7-22: Centralized PC Security Management 44

  45. Copyright Pearson Prentice-Hall 2010; edited by Yue Zhang, CSU-Northridge Standard Configurations for PCs May restrict applications, configuration settings, and even the user interface Ensure that the software is configured safely Enforce policies More generally, reduce maintenance costs by making it easier to diagnose errors 7-22: Centralized PC Security Management 45

  46. Copyright Pearson Prentice-Hall 2010; edited by Yue Zhang, CSU-Northridge Network Access Control (NAC) Goal is to reduce the danger created by computers with malware Control their access to the network Stage 1: Initial Health Check Checks the “health” of the computer before allowing it into the network Choices: Accept it Reject it Quarantine and pass it to a remediation server; retest after remediation 7-22: Centralized PC Security Management 46

  47. Copyright Pearson Prentice-Hall 2010; edited by Yue Zhang, CSU-Northridge Network Access Control (NAC) Stage 2: Ongoing Traffic Monitoring If traffic after admission indicates malware on the client, drop or remediate Not all NAC systems do this 7-22: Centralized PC Security Management 47

  48. Copyright Pearson Prentice-Hall 2010; edited by Yue Zhang, CSU-Northridge 7-23: Windows Group Policy Objects (GPOs) 48

  49. Copyright Pearson Prentice-Hall 2010; edited by Yue Zhang, CSU-Northridge Importance In an incident, you may lose all data that is not backed up P.331 Threats that Are Addressed by Backup Mechanical hard drive failure or damage in a fire or flood Data on lost or stolen computers is not available to the organization Malware can reformat the hard drive or do other data destruction 7-24: Data Protection: Backup 49

  50. Copyright Pearson Prentice-Hall 2010; edited by Yue Zhang, CSU-Northridge Scope of Backup Fraction of information on the hard drive that is backed up File/Directory Data Backup Select data files and directories to be backed up (Do not forget items on the desktop!) Not good for programs 7-25: Scope of Backup 50