Wrapup CSE497b - Spring 2007 Introduction Computer and Network - PowerPoint PPT Presentation

Wrapup CSE497b - Spring 2007 Introduction Computer and Network Security Professor Jaeger www.cse.psu.edu/~tjaeger/cse497b-s07/ CSE497b Introduction to Computer and Network Security - Spring 2007 - Professor Jaeger

Final • The final is on – Tuesday, May 8, 8:00 in 160 Willard (here) • Be late at your own peril (We may lock the door at 8:10) • You will have the full time to take the test, but no more • Coverage: – Anything we talked about in class … – or appeared in the readings – Mainly topics since mid-term • Types of questions – Constructive (here is scenario, design X and explain it) – Philosophical (why does Z argue that …) – Explanatory (what is the key tradeoff between A and B …) CSE497b Introduction to Computer and Network Security - Spring 2007 - Professor Jaeger Page 2

Prior Topics • Terminology – Any term defined in the early lectures • Crypto Algorithms – Diffie-Hellman and RSA – Keys • Crypto protocols – Public key – Secret key – Integrity, Authenticity, Secrecy CSE497b Introduction to Computer and Network Security - Spring 2007 - Professor Jaeger Page 3

Topics Since Midterm • Code Security • Access Control Principles • UNIX Security • Windows Security • Trusted Computing • Secrecy • Integrity • Intrusion Detection • MAC systems • Virtual machine systems CSE497b Introduction to Computer and Network Security - Spring 2007 - Professor Jaeger Page 4

Code Security • Problems – Buffer overflows, printf, integer overflows, names, characters • Considerations for writing and deploying secure code – Validate input (prevent vulnerabilities) – Minimize attack surface (number of points of potential vulnerabilities) – Minimize permissions – Safe transition of privilege via invocation – Return little information • Type safety – Implications to attacks above CSE497b Introduction to Computer and Network Security - Spring 2007 - Professor Jaeger Page 5

Access Control Principles • Protection System – Protection State – State Enforcer • Access Matrix – Use it – Variants (RBAC) – Security guarantees from policies • Protection and Security – Know the difference • Reference Monitor – Know the guarantees – Know how to apply them to other systems • How does X satisfy RM guarantees? CSE497b Introduction to Computer and Network Security - Spring 2007 - Professor Jaeger Page 6

UNIX and Windows • Subjects – UNIX: users; Windows: more complex • Objects – UNIX: files; Windows: more complex • User Authentication • Access Enforcement – Process – Implications for security • Transitions – UNIX: Setuid; Windows: Windows Services • Constrained execution – UNIX: chroot, nobody; Windows: Restricted contexts • General vulnerabilities CSE497b Introduction to Computer and Network Security - Spring 2007 - Professor Jaeger Page 7

Trusted Computing • Palladium • TPM • Know the difference • Mechanisms – Protected Storage – Attestation – How TPM supports • Boot guarantees CSE497b Introduction to Computer and Network Security - Spring 2007 - Professor Jaeger Page 8

Secrecy and Integrity • Secrecy – Secrecy and security – Multilevel security, Chinese Wall Security – Secrecy properties – Miscellaneous • Trojan horses, covert channels – Program secrecy (Denning) • Integrity – Integrity and security – Biba and LOMAC – Integrity realization – Privilege separation CSE497b Introduction to Computer and Network Security - Spring 2007 - Professor Jaeger Page 9

Intrusion Detection • Anomaly and misuse detection • Relation to access control • Network and host IDS • Positives/Negatives • Bayes ’ Rule Analysis CSE497b Introduction to Computer and Network Security - Spring 2007 - Professor Jaeger Page 10

MAC Systems and VM Systems • Relation to Reference Monitors • Mandatory Access Control • Multics • Transitions (all) • SELinux/LSM architecture • Virtual Machine architectures • VM principles • Xen enforcement • VM vs OS enforcement • Java enforcement CSE497b Introduction to Computer and Network Security - Spring 2007 - Professor Jaeger Page 11

The state of security … • … issues are in public consciousness – Press coverage is increasing … – Losses mounting … (billions and billions) – Affect increasing …… (ATMs, commerce) • What are we doing? “… sound and fury signifying nothing …” - W. Shakespeare (well, its not quite that bad) CSE497b Introduction to Computer and Network Security - Spring 2007 - Professor Jaeger Page 12

The problems … • What is the root cause? – Security is not a key goal … – … and it never has been … … so , we need to figure out how to change the way we do engineering (and science) … … to make computers secure. • Far too much misunderstanding about basic security and the use of technology • This is also true physical security CSE497b Introduction to Computer and Network Security - Spring 2007 - Professor Jaeger Page 13

The current solutions … • Make better software – “we mean it” - B. Gates (2002) – “no really …” - B. Gates (2003) – “Linux is bad too …” - B. Gates (2005) – “it ’ s in longhorn ...” - B. Gates (2006) • CERT/SANS-based problem/event tracking – Experts tracking vulnerabilities – Patch system completely broken • Destructive research – Back-pressure on product developers – Arms-race with bad guys • Problem: reactive, rather than proactive CSE497b Introduction to Computer and Network Security - Spring 2007 - Professor Jaeger Page 14

The real solutions … • Fix the economic incentive equation … – Eventually, MS/Sun/Apple/*** will be in enough pain that they change the way they make software • Education – Things will get better when people understand when how to use technology • Fix engineering practices – Design for security • Apply technology – What we have been talking about CSE497b Introduction to Computer and Network Security - Spring 2007 - Professor Jaeger Page 15

The bottom line • The Web/Internet and new technologies are being limited by their ability to address security and privacy concerns … • … it is incumbent in us as scientists to meet these challenges. – Evangelize importance of security … – Provide sound technologies … – Define better practices … CSE497b Introduction to Computer and Network Security - Spring 2007 - Professor Jaeger Page 16

Thank You!!! tjaeger@cse.psu.edu CSE497b Introduction to Computer and Network Security - Spring 2007 - Professor Jaeger Page 17