Usable security and the human in the loop Michelle Mazurek Some - - PowerPoint PPT Presentation
Usable security and the human in the loop Michelle Mazurek Some slides adapted from Lujo Bauer, Lorrie Cranor, Rob Reeder, Blase Ur, and Yinqian Zhang 1 Todays class Introducing me Introducing you Human Factors for Security and
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Some slides adapted from Lujo Bauer, Lorrie Cranor, Rob Reeder, Blase Ur, and Yinqian Zhang
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Network Security: PRIVATE Communication in a PUBLIC World. 2nd edition. Prentice Hall, page 237, 2002.
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Security Usability/HCI Usable Security Humans are a secondary constraint compared to security concerns Humans are the primary constraint, security is rarely considered Human factors and security are both primary constraints Humans considered primarily in their role as adversaries/attackers Concerned about human error but not human attackers Concerned about both normal users and adversaries Involves threat models Involves task models, mental models, cognitive models Involves threat models AND task models, mental models, etc. Focus on security metrics Focus on usability metrics Considers usability and security metrics together User studies are rare User studies are common User studies common,
distraction
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Security Usability/HCI Usable Security Humans are a secondary constraint compared to security concerns Humans are the primary constraint, security is rarely considered Human factors and security are both primary constraints Humans considered primarily in their role as adversaries/attackers Concerned about human error but not human attackers Concerned about both normal users and adversaries Involves threat models Involves task models, mental models, cognitive models Involves threat models AND task models, mental models, etc. Focus on security metrics Focus on usability metrics Considers usability and security metrics together User studies are rare User studies are common User studies common,
distraction
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Security Usability/HCI Usable Security What is the space of possible passwords? How can we make the password space larger to make the password harder to guess? How are the stored passwords secured? Can an attacker gain knowledge by observing a user entering her password? How difficult is it for a user to create, remember, and enter a graphical password? How long does it take? How hard is it for users to learn the system? Are users motivated to put in effort to create good passwords? Is the system accessible using a variety of devices, for users with disabilities? All the security/privacy and usability HCI questions How do users select graphical passwords? How can we help them choose passwords harder for attackers to predict? As the password space increases, what are the impacts on usability factors and predictability
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Security Usability/HCI Usable Security What is the space of possible passwords? How can we make the password space larger to make the password harder to guess? How are the stored passwords secured? Can an attacker gain knowledge by observing a user entering her password? How difficult is it for a user to create, remember, and enter a graphical password? How long does it take? How hard is it for users to learn the system? Are users motivated to put in effort to create good passwords? Is the system accessible using a variety of devices, for users with disabilities? All the security/privacy and usability HCI questions How do users select graphical passwords? How can we help them choose passwords harder for attackers to predict? As the password space increases, what are the impacts on usability factors and predictability
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Image from http://www.trypap.com
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Image from http://www.techradar.com
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Image from http://www.economist.com Image from http:// www.sciencedaily.com
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Image from http://www.wikipedia.org
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Image from http:// www.wikipedia.org Image from http://www.jhalderm.com
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Screenshot from http://www.tosdr.org
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Image from http://www.about.com
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Image from http://www.ftc.gov
Image from http:// www.makezine.com
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Image from http://www.nokia.com Image from http:// www.arstechnica.com
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Image from http:// www.motortrend.com Image from http:// www.allaboutsymbian.com Image from http:// www.hcwreview.com
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Image from http://www.quickmeme.com
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Case study #1:
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A User Study of Policy icy Cr Creat eation in a Flexible Access-Contr ion in a Flexible Access-Control System.
Lessons Learned from t
he Deployment of a Smartphone-Based Access-Contr Deployment of a Smartphone-Based Access-Control System.
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Getting keys 3.6 sec 5.4 sec Stop in front of door Door
Total 14.7 sec
σ = 3.1 σ = 3.1
5.7 sec
σ = 3.6 σ = 5.6
Door Closed Door Closed 8.4 sec 2.9 sec 3.8 sec Stop in front of door Getting phone Door
Total 15.1 sec
σ = 2.8 σ = 1.5 σ = 1.1 σ = 3.9
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Case Study #2
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[Adams & Sasse 99 … we’ll talk about this later]
[Zhang et. al, CCS 2010]
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p→ P
p→ P
p→ P
“password” “pa$sword”? “Password”? “pa$$word”? “Pa$sword”? “Pa$sword”? ┴
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CATEGORY EXAMPLE
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depth 1 depth 2 depth 3 depth 4 0% 10% 20% 30% 40% 50% Edit Dist Edit w/ Mov Loc Ind Pruned 26% 28% 25% 17% 39% 41% 37% 24% 41% 28% 30%
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http://www.usenix.org/events/upsec08/tech/full_papers/cranor/cranor.pdf
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Human Receiver
Intentions Motivation Attitudes and Beliefs Personal Variables Knowledge & Experience Demographics and Personal Characteristics Capabilities
Communication Behavior Communication Impediments
Interference Environmental Stimuli
Communication Processing
Comprehension
Knowledge Acquisition Application Knowledge Retention Knowledge Transfer
Communication Delivery
Attention Switch Attention Maintenance
Communication Communication Impediments
Interference Environmental Stimuli
Human Receiver
Intentions Motivation Attitudes and Beliefs Personal Variables Knowledge & Experience Demographics and Personal Characteristics Capabilities
Communication Processing
Comprehension
Knowledge Acquisition Application Knowledge Retention Knowledge Transfer
Communication Delivery
Attention Switch Attention Maintenance
Behavior
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Task Identification Task Automation Failure Mitigation User Studies Failure Identification Human-in- the-loop Framework User Studies
Identify points where system relies on humans to perform security-critical functions Find ways to partially or fully automate some
Identify potential failure modes for remaining tasks Find ways to prevent these failures
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Human Receiver
Intentions Motivation Attitudes and Beliefs Personal Variables Knowledge & Experience Demographics and Personal Characteristics Capabilities
Communication Behavior Communication Impediments
Interference Environmental Stimuli
Communication Processing
Comprehension
Knowledge Acquisition Application Knowledge Retention Knowledge Transfer
Communication Delivery
Attention Switch Attention Maintenance
Comprehension
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Internet Explorer cookie flag
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Task Identification Task Automation Failure Mitigation User Studies Failure Identification Human-in- the-loop Framework User Studies
Identify points where system relies on humans to perform security-critical functions Find ways to partially or fully automate some
Identify potential failure modes for remaining tasks Find ways to prevent these failures
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