Lecture Operating systems: A concept-based approach (2/e): Chapter 20 - Dhananjay M. Dhamdhere

PROPRIETARY MATERIAL. © 2007 The McGraw­Hill Companies, Inc. All rights reserved. No part of this PowerPoint slide may be displayed, reproduced or distributed in any form or by any means, without the prior written permission of the publisher, or used beyond the limited distribution to teachers and educators permitted by McGraw­Hill for their individual course preparation. If you are a student using this PowerPoint slide, you are using it without permission. Chapter 20: Distributed System Security Dhamdhere: Operating Systems— A Concept­Based Approach , 2 ed Slide No: 1 Copyright © 2008 Security issues in distributed systems • Interprocess messages travel over the network – Hence intruders can perpetrate attacks through messages Chapter 20: Distributed System Security Dhamdhere: Operating Systems— A Concept­Based Approach , 2 ed Slide No: 2 Copyright © 2008 Security threats in distributed systems • Following threats can be posed through messages – Leakage * Message contents are read by intruder – Tampering * Messages are corrupted or altered – Stealing * Resources are accessed without authorization – Denial of service * Authorized users are prevented from accessing resources Chapter 20: Distributed System Security Dhamdhere: Operating Systems— A Concept­Based Approach , 2 ed Slide No: 3 Copyright © 2008 Mechanisms and policies for distributed system security • Encryption ensures secrecy and integrity of meta data and messages • Key distribution center generates encryption keys for communication • Authentication is used to prevent masquerading Chapter 20: Distributed System Security Dhamdhere: Operating Systems— A Concept­Based Approach , 2 ed Slide No: 4 Copyright © 2008 Classes of security attacks • Four classes of attacks – Eavesdropping * Intruder listens to messages on the network – Message tampering * Intruder corrupts or alters messages – Message replay * Intruder inserts copies of old messages in message communication to fool processes – Masquerading * Intruder is able to pass off as an authorized user to perform computations and use resources Chapter 20: Distributed System Security Dhamdhere: Operating Systems— A Concept­Based Approach , 2 ed Slide No: 5 Copyright © 2008 ... - tailieumienphi.vn