ch15 - Chapter 15: Security Chapter 15: Security 15.2...

Info iconThis preview shows pages 1–11. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Chapter 15: Security Chapter 15: Security 15.2 Silberschatz, Galvin and Gagne 2005 Operating System Concepts Chapter 15: Security Chapter 15: Security The Security Problem Program Threats System and Network Threats Cryptography as a Security Tool User Authentication Implementing Security Defenses Firewalling to Protect Systems and Networks Computer-Security Classifications An Example: Windows XP 15.3 Silberschatz, Galvin and Gagne 2005 Operating System Concepts Objectives Objectives To discuss security threats and attacks To explain the fundamentals of encryption, authentication, and hashing To examine the uses of cryptography in computing To describe the various countermeasures to security attacks 15.4 Silberschatz, Galvin and Gagne 2005 Operating System Concepts The Security Problem The Security Problem Security must consider external environment of the system, and protect the system resources Intruders (crackers) attempt to breach security Threat is potential security violation Attack is attempt to breach security Attack can be accidental or malicious Easier to protect against accidental than malicious misuse 15.5 Silberschatz, Galvin and Gagne 2005 Operating System Concepts Security Violations Security Violations Categories Breach of confidentiality Breach of integrity Breach of availability Theft of service Denial of service Methods Masquerading (breach authentication) Replay attack Message modification Man-in-the-middle attack Session hijacking 15.6 Silberschatz, Galvin and Gagne 2005 Operating System Concepts Standard Security Attacks Standard Security Attacks 15.7 Silberschatz, Galvin and Gagne 2005 Operating System Concepts Security Measure Levels Security Measure Levels Security must occur at four levels to be effective: Physical Human Avoid social engineering, phishing, dumpster diving Operating System Network Security is as week as the weakest chain 15.8 Silberschatz, Galvin and Gagne 2005 Operating System Concepts Program Threats Program Threats Trojan Horse Code segment that misuses its environment Exploits mechanisms for allowing programs written by users to be executed by other users Spyware, pop-up browser windows, covert channels Trap Door Specific user identifier or password that circumvents normal security procedures Could be included in a compiler Logic Bomb Program that initiates a security incident under certain circumstances Stack and Buffer Overflow Exploits a bug in a program (overflow either the stack or memory buffers) 15.9 Silberschatz, Galvin and Gagne 2005 Operating System Concepts C Program with Buffer-overflow Condition C Program with Buffer-overflow Condition #include < stdio.h > #define BUFFER SIZE 256 int main(int argc, char *argv) { char buffer[BUFFER SIZE]; if (argc < 2) return -1; else { strcpy(buffer,argv[1]); return 0; } } 15.1015....
View Full Document

This note was uploaded on 01/21/2012 for the course COMPUTER CSCI 593 taught by Professor Hamnes during the Spring '11 term at Aston University.

Page1 / 43

ch15 - Chapter 15: Security Chapter 15: Security 15.2...

This preview shows document pages 1 - 11. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online