U.S. National Cybersecurity Understanding Internet Security

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U.S. National CybersecurityUnderstanding
Internet Security

• William J. Perry
• Martin Casado Keith Coleman Dan Wendlandt
• MSE 91SI
• Fall 2004
• Stanford University

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Announcements

• Axess Email lists
• Coursework Forum
• Bios/Photos

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Goal Provide Working Knowledge of Internet
Security
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Outline

• What is Security?
• Attack Classifications
• Internet Security Mechanisms
• Discussion Questions (if time)

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What is Security ?
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The Big Five

• Security is traditionally broken up into
• 1) Availability
• 2) Integrity
• 3) Confidentiality
• 4) Authentication
• 5) Access Control

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Security From What?

• What can disrupt the higher-level services
  running on the Internet?
• Attacks
• Accidents
• Failures

NASA Control Room
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Failures on the Internet

• Why do security failures matter?
• Security failures affect the Internets ability
  to function as a reliable and secure critical
  infrastructure.

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Vulnerabilities

• Def. vulnerability (n)
• a state with the potential to lead to a failure
• Where can vulnerabilities exist in technology?

Services (Amazon, SCADA) Applications (Word, IE,
Email Client) Service-Level Protocols (http,
smtp) Network and Network Protocols (ip,
tcp) Operating Systems (Windows, Linux, Cisco
IOS) Physical Hardware (cables, routers,
CPUs) Basic Infrastructure (electricity)
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Attack Classifications(not mutually exclusive)
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Vulnerabilities Attacks

• The nature of the network technologies,
  protocols, and operators are the basis for
  attacks.
• Attacks can (and will) come at vulnerabilities in
  every layer.
• Big Question What is it about the Internet
  architecture that causes these vulnerabilities to
  exist?

Humans
Attacks
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Scanning Fingerprinting
What is it?

• Reconnaissance technique to explore networks,
  classify analyze connected hosts, and identify
  potential vulnerabilities.
• Example nmap security scanner

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Exploits

• What is it?
• The use of vulnerabilities in or
  misconfiguration of software or hardware to gain
  access to information or resources on a system.
• Exploits may be manual or automated.
• worms/viruses are exploits with code to
  facilitate propagation.
• example Blaster worm exploits RPC bug

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Trojaned Software
What is it? Software/Hardware with hidden
functionality that its use allows an attacker an
avenue to access a system or its
information. This is sometimes also referred to
as a backdoor.
Example A free copy of MSWord downloaded off of
Kazaa may have been modified to include a trojan
leading to a compromise.
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Denial of Service
What is it?

• The malicious consumption of resources in order
  to make a system incapable of fulfilling its
  designed role.
• Attacks are often distributed to increase
  resource consumption (zombies or botnets).
• example SYN flood against Yahoo

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Social Engineering Attack

• What is it?
• Any attempt that employs non-technical means to
  attack a system. Often the attacker uses
  information gleaned from outside sources to
  produce false credentials (dumpster diving).
• Attacks are often hybrid, relying on human and
  technical factors.
• example Beagle virus used email domain name to
  pose as a message from the users ISP.

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Access Control Failures

• What is it?
• Failure to set up adequate access control
• Default configurations
• Privilege revocation
• Example default administrator password for
  windows

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Authentication Failures

• What is it?
• Some authentication schemes are better than
  others
• Passwords
• Public Key Crypto
• Example phishing schemes that steal passwords
  break the authentication model.

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Infrastructure Attack
What is it?

• An attack against the core systems that operate
  as the Internet infrastructure. Attacks can be
  either physical or virtual, often focusing on
  central points of failure.
• example Attack on root DNS servers.

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Insider Threats

• What is it?
• Attacks that exploit an existing trust
  relationship to harm the overall security of a
  system.
• example former employee uses knowledge of a
  companys network systems and passwords to steal
  customer information entrusted to the company

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Traffic Sniffing/Modification

• What is it?
• Using access to a link or infrastructure system
  to examine or modify the contents of Internet
  traffic. Similar to a phone tap, with ability to
  change contents.
• example ISPs potential for information
  gathering

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Dont Forget

• Attacks are only one of the reasons systems can
  fail. There are many other, perhaps less
  exciting, ways systems are vulnerable.

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Internet Security Mechanisms
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What is Cryptography

• A critical TOOL in securing information systems
  and their communications.
• You may have heard of
• SSL
• Trusted Computing
• Public Key Cryptography
• Tripwire

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Cryptography Overview

• Crypto can great hard guarantees (backed by
  math) in the digital world similar to those we
  have long relied upon for security in the
  physical world
• - Data Encryption (privacy)
• No one else can read my message
• - Data Integrity
• My message has not been modified
• My message is from who it says it is
• Also provides for some improved authentication
  schemes.

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Cryptography Examples

• How do these mechanisms function?
• (at 10,000 feet)

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Problems with Crypto

• Bad Standards
• WEP, CSS
• Bad Implementation
• IE, OpenSSL
• Attacks on Authentication
• Phishing, password sniffing
• Weak back-end
• Weak link, insider attacks
• Encryption is often slow cumbersome
• PKI has difficulty scaling to large numbers

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Ideal vs. Real Internet Security

• Ideally we can utilize authentication and access
  control to protect systems and data.
• In reality this is not practical.
• E.g. What if everyone needed to be authenticated
  to talk to you computer?
• Additionally, authentication schemes are only as
  secure as those using them.
• E.g. An uneducated but authenticated user may
  install a trojan.

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Attack Detection/Prevention

• Firewalls Software to inspect packets, compare
  them to rules and drop traffic specified by these
  rules.
• Intrusion Detection/Prevention Systems (IDS/IPS)
  Software to inspect traffic flows for
  signatures or other behavior that appears to be
  malicious.
• Anti-Virus Software Inspects files for signs of
  infectious programs and eliminates them.
• These mechanisms can either be deployed on
  individual hosts or on dedicated network servers.

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Patching

• Fix vulnerabilities in software that may lead to
  exploitation. Patch management is major hidden
  cost to companies.
• Important
• - Process is still embarrassingly manual
  (changing?).
• - Gap between release of patch first exploit
  in the wild is shrinking (Witty worm and
  zero-days).
• - Often patches are not applied to critical
  systems because updates sometimes have conflicts
  that can break software running on the systems.
• Do we patch?
• Check out Security Holes? Who Cares by Eric
  Rescorla. http//www.rtfm.com/upgrade.pdf

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Process, Education Risk Assessment

• Often forgotten as security mechanisms
• - Having well-defined and consistent
  preparation, response, and recovery plans across
  an organization.
• - Attempting to secure humans, often the weakest
  link.
• - Determining the danger associated with each
  potential vulnerability.

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Discussion Questions
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Attributability

• For traffic on the Internet, can we determine who
  a packet come from?
• Two levels
• Can we tell what computer sent a given
  packet?(what are the implications of source
  spoofing?)
• Can we attribute a packet to a human?
• - What does this say about our ability to catch
  and prosecute perpetrators of online attacks?
  What about active response?

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Determining Intent

• Can you infer intent from analyzing network
  traffic? What about at the application level?
• What is the different between a denial of service
  attack and normal overwhelming usage?
• What is more important, the intent or the result
  of Internet traffic?
• What about enablement versus use?

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Trust Relationships

• What are key trust relationships relating to
  cybersecurity? Think about
• - designers
• - developers
• - distributors
• - owners
• - operators
• - users
• If security is a weakest-link issue, what
  forces keep one of these trust links from
  breaking?

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The Power of the Core

• How much control do we have with determining
  where traffic flows on the Internet, and what
  entities have control over it?
• What can someone on route potentially do? How
  can you trust the integrity of what you see?
• What does it take to have control of the Internet
  core?

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Infrastructure Attacks

• How vulnerable is the actual Internet
  infrastructure to attacks?
• Could a single group bring down the Internet?
  What does this mean? What kind of resources
  would it take?
• How reliant is the Internet on a relatively few
  critical systems?
• What happens when you rely on the security of
  infrastructure that you have absolutely no
  control over? As a company? As a country? How
  does this compare to security in the physical
  world?

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Determining Identity

• How can we trust an Internet entity is who they
  say they are?
• Why is this process more difficult than it is in
  the brick mortar world?
• How important is this for a critical
  infrastructure?
• Do our solutions for providing identity scale to
  the millions of actions on the Internet?

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Overwhelming Complexity

• What does the extreme complexity of the Internet
  mean for our ability to secure it?
• Are there just too many things that could go
  wrong to ever possibly be able to completely rely
  on it?
• In what way does the complexity impact our
  ability to educate average users? Is user
  education necessary? Is effective user education
  even possible?
• Will the Internet become more or less complex to
  manage in the future?

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Why is this so hard?

• What are the major barriers to providing
  security guarantees for an information system on
  the Internet?
• What (or who) are the weak links for security
  systems?
• Can we ever really secure a usable Internet
  computer system? (e.g. directed attack)
• How does software size complexity relate to our
  ability to secure a system? What is zero-day?