Human Factors of Security Systems - Andrew Patrick€¦ · weakest link, and people are the weakest...

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Human Factors of Security SystemsAndrew Patrick, Ph.D.

Information Security GroupInstitute for Information Technology

http://iit-iti.nrc-cnrc.gc.ca

[email protected]://www.AndrewPatrick.ca

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2Andrew Patrick @ NRC Feb. 14, 2007

•The Book

•Collection of articles on human factors of security.

•sections on authentication mechanisms

•secure systems

•privacy

•design

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July 18-20, 2007

Carnegie Mellon University

Pittsburgh, PA

Symposium On Usable Privacy and Security

The conference. Tutorials, workshops, keynotes, the latest research.

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Usable Security (USEC'07)February 15-16, 2007

Trinidad/Tobago

A workshop co-located withThe Eleventh Conference on Financial Cryptography

and Data Security (FC'07)

The other conference, happening this week.

• Financial Cryptography is an interesting conference focusing on security issues for the financial sector.

• Based in the Caribbean!

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‘... security is only as good as it’s weakest link, and people are the

weakest link in the chain.’

- Bruce Schneier: ‘Secrets and Lies’ (2000).

When we talk about humans and security, this is the typical message that we hear.

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“... the human side of computer security is easily exploited and constantly

overlooked. Companies spend millions of dollars on firewalls, encryption and secure access devices, and it’s money

wasted, because none of these measures address the weakest link in

the security chain”

- Kevin Mitnick, 2000

… and here is another. Mitnick was referring to his successful social engineering attacks.

Bio from wikipedia:

…a famous computer cracker, who was convicted of wire fraud and of breaking into the computer systems of Fujitsu, Motorola, Nokia, and Sun Microsystems.Mitnick served five years in prison (four years of it pre-trial), 8 months of that in solitary confinement, and was released on January 21, 2000. During his supervised release, which ended on January 21, 2003, he was initially restricted from using any communications technology other than a landline telephone.

He offers security consulting services through his company Mitnick Security Consulting, LLC and has co-authored two books on computer security. The books are The Art of Deception (2002), which focuses on social engineering, and The Art of Intrusion (2005), focusing on real stories of security exploits.

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There is no problem so complex that it cannot simply be blamed on the pilot.

— Dr Earl Weiner

I want to draw a parallel between the state of information security today and the state of airline safety 20 years ago. Back then, it was very common to blame airline accidents on “pilot error”, without an investigation to factors that led to that error.

The same is true for information security today. We are too quick to blame the users, without spending enough time understanding, and remedying, the factors that lead to the users’ behavior.

A lot of progress was made in airline safety when a systems approach was adopted, and the same can be done for IT security.

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So, what do users do?

They write their passwords down and store them in unsafe places.

Any they make easy to remember (easy to guess) passwords.

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They share their passwords with friends and coworkers.

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And they give away their passwords to just about anybody who asks.

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• And they continue to support the spam industry.

• One study showed that 33% of people have clicked on links in spam messages.

• And 10% have bought products advertised in spam!

Email users 'sustaining spam industry'23 March 2005http://www.weboptimiser.com/search_engine_marketing_news/13020846.html

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And, they are susceptible to phishing attacks – being lured to false web sites to give-up their username/password credentials.

A recent report suggested that 5% of people respond to phishing messages.

Report on Phishing

A Report to the Minister of Public Safety and Emergency Preparedness Canada and the Attorney General of the United States

Binational Working Group on Cross-Border Mass Marketing Fraud October 2006

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the blame trap

James Reason:

• blaming the fallible individuals at the front end is universal,natural, satisfying, and convenient

• but it does little to solve the problem

• and may put focus on the wrong person

• and leads to ineffective fixes (e.g., training, procedures, policies, supervision)

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active errors

errors made by an individual that directly leads to a problem

e.g., sharing a password

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latent errors

• delayed-action errors made by a system or organization

• consequences are indirect

• often related to design, construction, operation, etc.

• e.g., Chernobyl accident

• e.g., not supporting collaboration between workers

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the organizational accident

James Reason, talking about Chernobyl

five phases:

1. organizational process leading to latent errors

2. error-producing conditions within specific places

3. active errors made by individuals

4. events in which one or more safeguards are by-passed

5. outcomes that vary in severity of consequences (free lessons vs. catastrophes)

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Zippy delivery, 7 minutes or it’s free

Clip from prevent-it.ca advertisement, WSIB Ontario

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Framework for Examining HCI and Security(Sasse et al., 2001)

Users

Technology

Goals & Tasks

Context

new topic: framework for understanding usability and security

Users

Technology

Goals & Tasks

Context

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cognitive psychology

• the study of the functions of the human mind

• features, characteristics, limitations

•thoughts, emotions, behaviors are systematic, predictable•we can design with them in mind

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human memory

characteristics of human memory

• limited capacity of working memory

• decay over time

• memory for gist & meaning rather than literal details

• strengthening by repetition, weakening by time

• cannot forget on demand

• recognition better than recall

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• memory is not a set of compartments where experiences are locked away

• memory is meaningful, constructions, schemas, etc.

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So, we should adopt techniques that make passwords more meaningful…

HUMAN SELECTION OF MNEMONIC PHRASE-BASED PASSWORDSCynthia Kuo, Sasha Romanosky, and Lorrie Faith Cranor (Carnegie Mellon University) SOUPS 2006

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cognitive passwords (personal history or preferences)

– mother’s maiden name

… and we can based passwords on knowledge, rather than on arbitrary memories

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http://www.nature.com/neuro/journal/v4/n11/full/nn739.html

… and we know that we are much better at recognition tasks then we are for recall tasks.

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… and promote systems based on recognition rather than recall

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… because the evidence is that we will remember passwords based on recognition better

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Here is another example of a recognition-based authentication system

déjà vuhttp://www.ischool.berkeley.edu/~rachna/dejavu/

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relaxing “three strikes” rule can reduce password resets by 44%, with little

impact on vulnerability if strong passwords enforced

… and since memory is imperfect and reconstructive, we can accommodate it by relaxing some arbitrary restrictions

most failures to remember passwords are confusions, not forgetting (wrong password, old password)

"Ten strikes and you’re out": Increasing the number of login attempts can improve password usability (revised February 18 2003)Sacha Brostoff and Angela Sasse HCISEC workshop, 2003

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knowledge and motivation

• security is at best an enabling task, and at worst a barrier to real work

• security consciousness can be linked to fear of being labeled“paranoid” or untrusting

• password sharing as a sign of trust

• perceptions of unimportance: nobody will target me, and what would they get if they did

• perceptions of helplessness: hackers will get in anyway

• security policies and procedures unrealistic and user not accountable

• using security encourages others to try to break-in

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… so we can train people why and how to use passwords

University of Michigan

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technology

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passwords or PINs

are you asking users to use passwords, or PINs, or both

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• arbitrary password restrictions?

• exactly 8 characters?

• must have punctuation?

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number of passwords

I use a unique password for each login account that I have.

I have collected about 200 different passwords.

I use pwsafe to maintain them. Protected by a master key, and stored on an encrypted USB device.

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single sign-on

we don’t use single sign-on, or even password synchronization, enough

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ambushing

we often require people to change their password immediately, with no warning, when they want to do their primary task

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public key systems (PKI)

people often point to PKI systems as the solutionusers will have a cryptographic key, and use it to authenticate themselves

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Why Johnny Can’t Encrypt

• only 33% of people could sign and encrypt email

• 25% accidentally exposed the secret that was to be protected

Why Johnny Can’t Encrypt:A Usability Evaluation of PGP 5.0Alma WhittenJ. D. Tygar

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on the surface, an attractive and simple interface…

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people did not know that they had to get public keys from other people

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if they knew they needed keys for other people, they had trouble doing so

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people failed to develop a conceptual model of the security operations

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goals and tasks

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security interferes with “real” work

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cost of authentication failures

time

embarrassment

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teamwork and collaboration

• people usually work in groups, where information sharing is essential

• and yet, the information system are often not designed to support the level of sharing that goes on

• with no other alternative, users will resort to nasty habits, such as password sharing

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context

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imagine you are using the machine and can’t remember your password, or can’t get your fingerprint to be recognized

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imagine you are working in an organization that has this as their physical security measure

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hot topics

new topic: current hot topics in usability and security

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user authentication

traditionally has been the username and password

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two-factor authentication

something you have (card, token)something you know (password, PIN)something you are or do (biometric, signature)

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US banks

•Federal Financial Institutions Examination Council •new requirements to implement two-factor authentication for Internet banking

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one-time passwords

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challenge questions

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off-line attacks

these authentication methods work against simple off-line attacks where credentials obtained by •data breaches, •simple phishing, •key loggers

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dynamic attacks

does not work against dynamic attacks

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man-in-the-middle

the user does all the authentication

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•bad software running on the client computer•installed via luring, piggy backing, viruses (e.g., Super Bowl web site used JavaScript exploit in unpatched computers)•most common Trojans are shells designed to download specific software

•can hijack secure financial sessions and insert fraudulent transactions•relies on the user to do all the authentication for it

•part of Greek mythology•The Greek siege of Troy had lasted for ten years. The Greeks devised a new ruse: a giant hollow wooden horse. It was built by Epeius and filled with Greek warriors led by Odysseus. The rest of the Greek army appeared to leave, but actually hid behind Tenedos. Meanwhile, a Greek spy, Sinon, convinced the Trojans that the horse was a gift despite the warnings of Laocoon and Cassandra; Helen and Deiphobus even investigated the horse; in the end, the Trojans accepted the gift. In ancient times it was customary for a defeated general to surrender his horse to the victorious general in a sign of respect. It should be noted here that the horse was the sacred animal of Poseidon; during the contest with Athena over the patronage of Athens, Poseidon gave men the horse, and Athena gave the olive tree.

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“Zombies” are computers that are being controlled remotely in order to do malicious tasks.

Zombies organized together into “botnets” for efficient control. These are often rented out to cyber criminals.

Estimates are that 80% of spam email is sent by Zombies. New zombies believed to responsible for the massive increases in spam over the past 3-4 months

Zombies also used for phishing, distributed denial of service attacks, and click fraud.•distributed denial of service attacks are often against anti-spam organizations and other spammers

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site authentication

•authenticating the site to the user•used to prevent phishing attacks

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phishing

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Link in the email does not lead to Paypal, but instead to a server in China.

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This attacks actually writes the address bar, making it harder to recognize as a scam.

•Notice that the user is asked for their PIN for their bank card!•This is the most common type of phishing attack because of the ease of “cashing” (to be discussed later).

From the Anti-Phishing Working Group

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The link shows tdcanadatrust.com, but the actual destination is tdcanadatrust.go.ro, and that is actually a server in Romania

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The real destination for the link is niccakorea.com, a server in Korea

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Notice how well the Scotiabank interface is replicated. There are few cues to indicate that this is not the authentic site.

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From the Anti-Phishing Working Group, December 2006 data.

The most common host for fake phishing sites is the USA, because of trojans and “zombie” computers.

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SSL certificates

•supposed to provide site authentication•but, we have seen, anybody can buy a certificate•and many web sites don’t use them properly (e.g., http on page with login form)

•see Canadian Internet Registration Authority, cira.ca•and browsers/users not good at checking certificates

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SiteKey•method used by Bank of America to identify site•requires users to notice that the personalized keys are not present during this transaction•combined with machine fingerprinting, so challenge question presented if login from new machine•does not protect against bad user behavior (see Schecter article and my critique)•does not project against man-in-the-middle attacks and trojans•at least one man-in-the-middle attack against SiteKey seen in the wild!

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single sign-on, one master password

random unique password for each site

password is never stored, but regenerated as needed

site labeling, so imposter sites are revealed

passpet.org

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biometrics

NEW TOPIC: biometrics

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0123456789

10Ideal

Hand

Face

Speech

Iris

retina

Signature

Fingerprint

UsabilityAccuracy

from Coventry book chapter

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fingerprints

•

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•misconceptions about using scanners (rolling, swiping, tip-only, pressure)

• ergonomic issues with finger placement on scanners

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eye positioning

glasses, small eyes, dark irises

feedback on false rejections

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system provides feedback on the screen about eye position, but you can’t see it because you are looking at the sensor

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feedback and training

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transparency of operations

the best systems provide information about operations, such as capture, encoding, and recognition steps

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integration

the best systems are well integrated into the host, such as one-touch unlocking of screen savers, or context-menu file encryption

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public opinions

• security as an “enabling task” that gets in the way (Sasse)

• biometrics can be seen as unhygienic, stressful (Coventry)

• some fear of bodily harm to obtain biometric information (movies)

•union at Pearson airport objecting to iris recognition due to infra-red light

• lack of understanding about biometric templates and storage mechanisms

• opinion polls show weak support and concerns (e.g., TNS/TRUSTe 2005)

•more support in recent polls

• some cross-cultural differences (within Europe; US/Canada)

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privacy

• deployments likely covered by provincial and/or federal privacy legislation

• privacy impact assessments would be required

• some tools and guidelines are emerging• bioprivacy.org• Ontario Privacy Commissioner recommendations for possible Toronto anti double-dipping deployment

• require: encryption, single use, no match to latents, strict access controls, separate storage of personal information

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universal, public identifier

•biometrics provides a universal, public identifier•this leads to universal risk•what is usually needed is a specific, secret identifier

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Clip from the film Minority Report, starring Tom Cruise

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Sarnoff patent application for iris biometric information from moving subjectsimilar to Minority Reportarray of cameras that capture multiple images until at least one good one is obtained

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increased risk

•biometrics only as good as the registration process and the security mechanisms•violations can lead to increased risk if there is a false sense of security•can lead to a false sense of confidence in the authenticity of transactions

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identity theft

NEW TOPIC: The term "identity theft" is an oxymoron.[3] It is not possible to steal a human identity. Human identity is a psychological thing, or the subject of philosophical conversation.[4]. (Wikipedia)

see Bruce Schneier’s essays for good insights

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Video from Citibank advertisement

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impersonation

The real crime of identity theft is impersonation – using some credentials to claim you are someone else

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fraud

… and then the impersonator commits fraud, which is defined as deception for persona gain

This is not a new crime.

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authentic user not present

It is important to note that when the fraud takes place, the authentic user is not present.

So attempts to train users, or provide strong authentication, are not going to do any good.

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credentials for impersonation

The credentials used for the impersonation are not in the hands of the user, and may have been obtained without any involvement of the user (e.g., database breach)

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credential receiver

The credential receiver (bank or other institution) is the only one in a position to catch and prevent fraud

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wrong incentives

•but the institutions do not have the incentives to prevent fraud•positive incentive to allow transactions•little or no negative incentives if fraud is committed •e.g., recent case of mortgage fraud – default is that fraudster or the bank gets the property

•In a 2005 ruling -- Household Realty v. Liu -- the court said that a fraudulent home sale was nonetheless valid once the land title has been registered. The Liu case involved a woman who sold the family home without the consent or knowledge of her husband.

•The Ontario Court of Appeal Feb 6 2007 closed a loophole that had allowed fraudsters to sell homes from under the unsuspecting feet of those who owned them. In a 5-0 ruling, the court said that banks and other lenders will pay a painful price if they do not diligently research mortgage applications to ensure that they are not being made unwitting parties to a swindle.

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weak authentication

why am I receiving dozens of pre-filled credit applications each year? These are one of the favorite targets during dumpster diving.

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protect the transaction

•the fraud occurs at the time of the transaction (“cashing” after “phishing”)•the solution is to protect the transaction, not the credential•why do I not keep my credit card information secret –because the bank protects the transactions•verify the transaction based on risk parameters (see RSA solution)•limit possible transactions (e.g., view and internal transfers only)

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The Economy of PhishingChristopher Abad, Cloudmark

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security administrators

•it is easy to fall into the blame trap again when thinking about security administrators•but consider their job and work environment•security operations are precarious and getting worse•small changes have large impacts•systems can already be insecure, awaiting hackers•new threats daily•insiders are the greatest threat•they don’t own or control the equipment•multiple, limited tools for monitoring•limited views•special expertise and complex interfaces•24/7, real-time

•and when you get it right, nobody notices

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taken from Steve Chan (UC Berkeley) presentation at SOUPS 2005different work practices require different toolsGUIs don’t scale or provide the level of controlneed for integrated tools and visualization

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users make security errors because…

Conclusions…

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designs give no/wrong cues

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unattainable cognitive tasks

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insufficient knowledge

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a safety-critical approach to information security

I am arguing for a safety-critical approach to information security

Analyze the system as a whole, not just users, or technology, or operators

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aligning primary and secondary goals

The users’ primary goal is often in conflict with the secondary goal of maintaining good security. This leads to the belief that there must be a trade-off between usability and security.

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security and economics

“More and more people are coming to realise that security failures are often due to perverse incentives rather than to the lack of suitable technical protection mechanisms.” (Ross Anderson)

• the person guarding the system is not the person who suffers when the security mechanisms fail

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Are users really the weakest link in the security chain?

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… and just in case you think Microsoft Vista is going to solve all of our problems…

Clip from Apple Computer advertisement

Human Factors of Security Systems - Andrew Patrick€¦ · weakest link, and people are the weakest...

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