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

CSE497b Introduction to Computer and Network Security - Spring 2007 - Professor Jaeger

Wrapup

CSE497b - Spring 2007 Introduction Computer and Network Security Professor Jaeger

www.cse.psu.edu/~tjaeger/cse497b-s07/

Page 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 …)

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Page CSE497b Introduction to Computer and Network Security - Spring 2007 - Professor Jaeger

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

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Page CSE497b Introduction to Computer and Network Security - Spring 2007 - Professor Jaeger

Topics Since Midterm

• Code Security
• Access Control Principles
• UNIX Security
• Windows Security
• Trusted Computing
• Secrecy
• Integrity
• Intrusion Detection
• MAC systems
• Virtual machine systems

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Page CSE497b Introduction to Computer and Network Security - Spring 2007 - Professor Jaeger

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

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Page CSE497b Introduction to Computer and Network Security - Spring 2007 - Professor Jaeger

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?

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Page CSE497b Introduction to Computer and Network Security - Spring 2007 - Professor Jaeger

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

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Page CSE497b Introduction to Computer and Network Security - Spring 2007 - Professor Jaeger

Trusted Computing

• Palladium
• TPM
• Know the difference
• Mechanisms

– Protected Storage – Attestation – How TPM supports

• Boot guarantees

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Page CSE497b Introduction to Computer and Network Security - Spring 2007 - Professor Jaeger

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

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Page CSE497b Introduction to Computer and Network Security - Spring 2007 - Professor Jaeger

Intrusion Detection

• Anomaly and misuse detection
• Relation to access control
• Network and host IDS
• Positives/Negatives
• Bayes’ Rule Analysis

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Page CSE497b Introduction to Computer and Network Security - Spring 2007 - Professor Jaeger

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

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Page CSE497b Introduction to Computer and Network Security - Spring 2007 - Professor Jaeger

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)

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Page CSE497b Introduction to Computer and Network Security - Spring 2007 - Professor Jaeger

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

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Page CSE497b Introduction to Computer and Network Security - Spring 2007 - Professor Jaeger

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

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Page CSE497b Introduction to Computer and Network Security - Spring 2007 - Professor Jaeger

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

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Page CSE497b Introduction to Computer and Network Security - Spring 2007 - Professor Jaeger

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 …

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Page CSE497b Introduction to Computer and Network Security - Spring 2007 - Professor Jaeger

Thank You!!!

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tjaeger@cse.psu.edu