Computer Security and Cryptography

Computer Security and Cryptography

Partha Dasgupta, Arizona State University

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The Problem

If I didn't wake up, I'd still be sleeping.

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Not just hype + paranoia

Internet hosts are under constant attack Financial losses are mounting Miscreants are getting smarter

(and so are consumers)

“National Security” risks were stated and then underplayed Data loss threatens normal users, corporations, financial

institutions, government and more

Questions:

HOW? WHY? and What can we do?

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Overview

Part 1: Security Basics Part 2: Attacks Part 3: Countermeasures Part 4: Cryptography Part 5: Network Security Part 6: System Security Part 7: State of the Art and Future

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Part 1: Security Basics

Computer and Network Security basics Hacking Attacks and Risks Countermeasures Secrets and Authentication Paranoia

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Computer and Network Security

Keep computers safe from program execution that is not authorized

Keep data storage free from corruption Keep data storage free from leaks Keep data transmissions on the network private and un-

tampered with Ensure the authenticity of the transactions (or executions) Ensure that the identification of the human, computer,

resources are established With a high degree of confidence Do not get stolen, misused or misrepresented

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Hacking or Cracking

Plain old crime Phone Phreaking Credit cards, the old fashioned way Technology Hacks

Design deficiencies and other vulnerabilite ATM, Coke Machines, Credit Cards, Social Engineering Software hacks Second channel attacks RFID issues Cell phone vulnerabilities Grocery cards?

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Attacks and Risks

“Attacks” An attack is a method that compromises one or more of:

- privacy (or confidentiality)- data integrity- execution integrity

Attacks can originate in many ways System based attacks Network based attacks “Unintended Consequences”

Risk – a successful attack leads to “compromise” Data can be stolen, changed or “spoofed” Computer can be used for unauthorized purposes Identity can be stolen RISK can be financial

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Attack Types

System based attacks Virus, Trojan, rootkit Adware, spyware, sniffers

A program has potentially infinite power Can execute, spawn, update, communicate Can mimic a human being Can invade the operating system

Network based attacks Eavesdropping Packet modifications, packet replay Denial of Service

Network attacks can lead to data loss and system attacks

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Countermeasures

System Integrity Checks Virus detectors Intrusion detection systems Software signatures

Network Integrity checks Encryption Signatures and digital certificates Firewalls Packet integrity, hashes and other cryptographic protocols

Bottom Line: We have an arsenal for much of the network attacks System security is still not well solved

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What is at Risk?

Financial Infrastructure Communication Infrastructure Corporate Infrastructure Confidentiality and Privacy at many levels Economy Personal Safety

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The Shared Secret Fiasco

Our authentication systems (personal, financial, computing, communications) are all based on “shared secrets”

ID numbers, Account numbers, passwords, SS#, DOB

When secrets are shared, they are not secrets

They will leak!

Given the ability of computers to disseminate information, all shared secret schemes are at extreme risk

Media reports of stolen data is rampant

• The Fake ATM attack

• The check attack

• The extortion attack

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How do secrets leak?

Malicious reasons Simple mistakes Oversight Bad human trust management Bad computer trust management “Nothing can go wrong”

Please believe in Murphy!

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Keeping Secrets?

Simple answer, not possible. Encryption is good, but data has to be unencrypted

somewhere “Disappearing Ink”? Use paper based documents, not scanned.

Public Key Encryption has much promise (PKI systems) Shared secrets need to be eliminated as much as possible Separate out of band communications

Phone, postal mail, person-to-person

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Authentication

Shared secrets are used for authentication Username/passwords

Multi-factor authentication What you know What you have What you are, what you can do.

Most of the authentication methods are quite broken Designed when networking was not around PKI systems are better, but not deployed Too many false solutions (dangerous, gives a feeling of security)

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Passwords

The password is known to the host and the client Under some password schemes the host does not know the

password (e.g. Unix)

Passwords can leak from host or from client Same password is used for multiple sites Password managers are not too effective “Good passwords” are not as good as you think Invented for a completely different purpose, using

passwords on the web, even with SSL encryption, is a bad idea

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False Solutions

Biometrics A digital bit string, or password that cannot be changed Plenty of attacks possible, including framing

RFID identification Plenty of attacks possible

Multi-Factor authentication Better, but still not good

Smart cards (the not-so-smart ones) Again, based on shared secrets, have attacks and limitations

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Paranoia?

A large number of computers (consumer, business) are compromised or used for fraud

Viral infections, zombies Many web servers are for fraudulent reasons

Spam is an indicator Unprecedented lying, cheating

Adware, popups, spyware All attempting to mislead, steer, and victimize

Identity theft, financial theft, cheating Probably at an all time high

Security Awareness is often coupled with paranoia It is necessary to be paranoid!

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What is the point of an attack?

Get your shared secrets for financial gain

Espionage Disruption

PersonalCorporateFinancial

System Identification

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Computer Security

Software needs to be verifiably untampered and trusted Networks need to be free from tampering/sniffing Data has to be secure from stealing and tampering End user protection

A coalescing of software, hardware and cryptography along with human intervention and multi-band communication.