© 2015 Pearson Education Ltd. Chapter 9 Chapter 9

© 2015 Pearson Education Ltd.  Explain the necessity for backup.  Describe backup scope and methods.  Describe the different RAID (redundant array of independent disks) levels.  Explain the need for data storage policies.  Explain database protections.  Explain the need for database access controls, auditing, and encryption.  Describe the difference between data leakage and data theft.  Explain data deletion, destruction, and disposal.  Explain digital rights management (DRM) and how it can prevent data loss. 9-2

© 2015 Pearson Education Ltd. 9-3

© 2015 Pearson Education Ltd.  In prior chapters we focused on ◦ Protecting data as it passed over networks (Chapter 3) ◦ Hardening hosts that store data (Chapter 7) ◦ Securing applications that process data (Chapter 8)  This chapter will emphasize the protection of stored data 9-4

© 2015 Pearson Education Ltd. 9.1 Introduction 9.2 Data Protection: Backup 9.3 Backup Media and RAID 9.4 Data Storage Policies 9.5 Database Security 9.6 Data Loss Prevention 9-5

© 2015 Pearson Education Ltd.  Data are the principal elements of any information system  Businesses gather enormous amounts of data ◦ Information is then extracted for decision making ◦ Data are valuable assets that are core components of a larger corporate strategy ◦ Source code, intellectual property, user data, etc. must all be protected 9-6

© 2015 Pearson Education Ltd.  This chapter will primarily focus on securing data while it is being stored  More specifically: ◦ How backup can prevent accidental data loss ◦ How to securely store data in a database ◦ How to prevent data from being taken out of the corporation ◦ How to securely dispose of data 9-7

© 2015 Pearson Education Ltd. 9.1 Introduction 9.2 Data Protection: Backup 9.3 Backup Media and RAID 9.4 Data Storage Policies 9.5 Database Security 9.6 Data Loss Prevention 9-8

© 2015 Pearson Education Ltd.  Image Backup ◦ Everything, including programs and settings ◦ Image backup is very slow ◦ Data files change the most rapidly, so doing several file/directory data backups for each image backup may be appropriate  Shadowing ◦ A backup copy of each file being worked on is written every few minutes to the hard drive, or to another location 9-9

© 2015 Pearson Education Ltd. 9-10

© 2015 Pearson Education Ltd.  Continuous Data Protection (CDP) ◦ Used when a firm has two server locations ◦ Each location backs up the other in real time ◦ Other site can take over very quickly in case of a disaster, with little data loss ◦ Requires expensive high–speed transmission link between the sites 9-11

© 2015 Pearson Education Ltd. PCs back up one another. Data is stored redundantly. Security issues must be addressed. PCs back up one another. Data is stored redundantly. Security issues must be addressed. 9-12

© 2015 Pearson Education Ltd. 9.1 Introduction 9.2 Data Protection: Backup 9.3 Backup Media and RAID 9.4 Data Storage Policies 9.5 Database Security 9.6 Data Loss Prevention 9-13

© 2015 Pearson Education Ltd.  Data Retention Policies ◦ There are strong legal requirements for how long certain types of data must be kept ◦ The legal department must get involved in retention policies  Auditing Policy Compliance ◦ All policies should be audited ◦ Includes tracing what happened in samples of data 9-14

© 2015 Pearson Education Ltd.  Benefits of Retention ◦ Major part of corporate memory ◦ Can retrieve old for current purposes  Dangers of Retention ◦ Legal discovery process ◦ Defendant must supply relevant s ◦ Potentially very damaging information ◦ Always expensive ◦ Even though very expensive to retrieve, firms must pay whatever is necessary to do so 9-15

© 2015 Pearson Education Ltd.  Accidental Retention ◦ Even if firms delete from mail servers, may be stored on backup tapes ◦ Users will often store copies on their own computers 9-16

© 2015 Pearson Education Ltd.  Message Authentication ◦ Spoofed messages can frame employees or the firm itself ◦ Need message authentication to prevent spoofed sender addresses  User Training ◦ Never put anything in a message that you would not want seen in court, printed in the newspaper, or read by your boss 9-17

© 2015 Pearson Education Ltd. 9.1 Introduction 9.2 Data Protection: Backup 9.3 Backup Media and RAID 9.4 Data Storage Policies 9.5 Database Security 9.6 Data Loss Prevention 9-18

© 2015 Pearson Education Ltd.  Databases ◦ Often used in mission-critical applications ◦ Require additional security precautions ◦ Relational databases: Tables (relations) with rows (records) and columns (attributes) ◦ As discussed earlier, avoid SQL injection attacks 9-19

© 2015 Pearson Education Ltd. 9-20

© 2015 Pearson Education Ltd.  Databases ◦ Restrict Access to Data  Restrict users to certain columns (attributes) in each row  For instance, deny access to salary column to most users  Limit access control to rows  For instance, only rows containing data about people in the user’s own department 9-21

© 2015 Pearson Education Ltd. 9-22

© 2015 Pearson Education Ltd.  Databases ◦ Restrict granularity (level of detail)  Prevent access to individual data  Allow trend analysts to deal only with sums and averages for aggregates, such as departments ◦ Restrict information about the structure of the database itself (data model)  Knowledge about the data model can make SQL injection much easier 9-23

© 2015 Pearson Education Ltd.  Database Access Control ◦ Restrict access to databases via database management systems (e.g., Microsoft SQL Server, MySQL, IBM DB2, Oracle, etc.) ◦ Rename administrator account, disable guest/public accounts, lowest possible permissions necessary  SQL Injection Attacks ◦ Data must be sanitized to remove unacceptable characters ◦ Stored procedures can be used to sanitize and validate incoming data 9-24

© 2015 Pearson Education Ltd. 1. Windows authentication 2. SQL Server authentication 3. Password policy options 9-25

© 2015 Pearson Education Ltd.  Database Auditing ◦ Collect information about users’ interactions with databases ◦ Policy driven, reflecting legal and regulatory obligations  What should be audited? ◦ Logins, changes to the database, warnings, exceptions, and special access 9-26

© 2015 Pearson Education Ltd.  Trigger - Code that is automatically run when changes are made to a database  Data Definition Language (DDL) trigger ◦ Used to produce automatic responses if the structure of the database has been altered (e.g., create new table, drop a table, alter properties of an existing table)  Data Manipulation Language (DML) trigger ◦ Used to produce automatic responses if the data has been altered (e.g., data are inserted, updated, or deleted) 9-27

© 2015 Pearson Education Ltd. CREATE TRIGGER EmployeeSalaryChange ON Employees FOR UPDATE AS varchar(1000) varchar(20) varchar(20) int int IF UPDATE (Salary) = = = Salary FROM deleted d = Salary FROM inserted = 'I just wanted to let you know ' ' changed their salary ' to EXEC = 'Somebody changed their GO 9-28

© 2015 Pearson Education Ltd. 9-29

© 2015 Pearson Education Ltd.  Key Escrow ◦ Loss of the key is disastrous  Not like losing a password that can be reset ◦ Key escrow stores a copy of the key in a safe place ◦ Bad if managed by user  May not do it  May not be able to find it  If fired, may refuse to give it back, locking up all data on the computer ◦ Central key escrow on a corporate server is better 9-30

© 2015 Pearson Education Ltd. 9.1 Introduction 9.2 Data Protection: Backup 9.3 Backup Media and RAID 9.4 Data Storage Policies 9.5 Database Security 9.6 Data Loss Prevention 9-31

© 2015 Pearson Education Ltd.  Spiders (crawlers) - Navigate the web gathering, organizing, and indexing web content  Web Scraper - Tool that extracts predefined data from specified webpages  Can aggregate extracted data from multiple websites  Mashup - Combining data from various sites or applications 9-32

© 2015 Pearson Education Ltd.  Data Destruction Is Necessary ◦ Backup media are not needed beyond their retention dates if…  a computer is to be discarded  the computer is to be sold or given to another user ◦ Drive-wiping software for hard drives  Reformatting the hard drive is not enough ◦ Shred CDs and DVDs 9-33

© 2015 Pearson Education Ltd. 9-34

© 2015 Pearson Education Ltd.    rity/current.asp rity/current.asp    

All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording or otherwise without the prior written permission of the publisher. © 2015 Pearson Education Ltd.