HTML5: Risky Business or Hidden Security Tool Chest

Johannes B. Ullrich, Ph.D.

jullrich@sans.edu

About Me

Hosted by OWASP & the NYC Chapter

• Dean of Research, SANS Technology Institute

• Living in Jacksonville FL (aka Southern GA)

• SANS Internet Storm Centerhttps://isc.sans.edu

• Created DShield.org• Instructor for SANS• Past: Physicist, Web Developer

What is HTML5

• Collection of JavaScript APIs supported by some modern browsers in some ways and sometimes they even work.

• Features to enable modern desktop like applications and support mobile devices

• 5th Revision of the HTML Standard

What is this talk about?

• Ideas to improve security by using HTML5 responsibly

• What are some of the security challenges that HTML5 addresses well (or doesn’t)

• What are some of the limitations we have to consider

Authentication

• Exclusive vs. Inclusive Authentication Methods:– Inclusive:

Proof the identity of the user

– Exclusive: Disproof the identity of the user

What the Factor?

Segway: Multi Factor Authentication• Single Factor: Password• Two Factor: Password AND (Token|Biometric)• 1 ½ Factor: Password and Cookie• ½ Factor: Password

OR (Token|Biometric)

HTML5 Components

• Local Storage / Session Storage• Canvas• Geolocation• Media Capture• Notifications• Accelerometer• Encryption

Local and Session Storage

• New JavaScript API to store data on client• Protected by “same origin”• Local Storage:

– No defined expiration– Accessible by all browser windows

• Session Storage:– Expired when window is closed– Scope limited to current window

Local Storage: Persistent Cookie

• Alternative to Flash cookie for “1 ½ Factor” login

• Part of an “Evercookie”• Can be used for good (additional

authentication) or evil (more user tracking)• Exposed to XSS attacks• Similar to cookies in scope and security

Session Storage: Identifying users

• Can be used to store session token• Breaks CSRF (good!)• User is logged out when they close the

browser window (not entire browser)• Multiple users can use the same browser (is

this a good thing?)• Easier log out, more secure session tracking,

can be used alongside cookies.

Risks

• Risks:Storing too much data on the client!Can’t enforce “secure” transmission over SSLCan’t protect from JavaScript/XSS (no httponly)

Examples:– storing confidential data on mobile devices– Pushing data to the client the client is not

authorized to see.

Can I use it?

http://caniuse.com/#feat=namevalue-storage

Canvas

• Allows drawing in the browser• Interactive image applications• Can be used for graphical login schemes

– CAPTCHAs– Pattern based login

Image Login

• Display image, user identifies features• Done in Windows 8/RT for mobile login

(“Pattern Login”, “Picture Password”)

Image:Microsoft

“Connect the Dots”

• Implemented in Android• Good user acceptance for mobile login• No good studies yet as to how users select

patterns

Image: Extremetech.com

Demo

• Demo: “Connect the Dots” for the web• http://authonthemove.com• See Github for code repository

Can I use it?

http://caniuse.com/#feat=canvas

Geolocation

• JavaScript API provides access to devices built in sensors like GPS

• Can be very accurate• Can also be spoofed easily

Image: Mozilla.org

Geolocation for Authentication

• Only useful on mobile devices• Can be used to exclude users, but not to

replace traditional authentication• Observe sudden changes in location• Combine with careful browser fingerprinting

techniques

Can I use it?

Media Capture

• aka getUserMedia/Stream API• Limited support (Chrome, Firefox, Blackberry)• Some potential for biometrics:

– Face recognition– Hand signals / gestures– Fingerprint?

Implementations

• Face recognition libraries:– http://neave.github.io/face-detection/

Difficulties

• Hard to acquire sufficient detail• So far, in particular on mobile devices, more of

a gimmick then a serious authentication feature

• Possibility to use “finger print”, but current cameras not sufficient to acquire image

Can I use it?

http://caniuse.com/#feat=stream

Accelerometer

• Only useful for mobile devices• Move the phone in a pattern to authenticate• Detect step/walking pattern• Detect if user/phone is at rest or on the move• Can be spoofed (but not readily)• Not easy to reproduce• Adding sensors like compass may help.

Can I use it?

http://caniuse.com/#feat=deviceorientation

Notifications

• Popup Notifications sent by the server to notify the user

• Initiated by server– Local Notifications: Require browser to be open,

widely supported– Push Notifications: Safari Only

Bad stuff happened!

• Notify the user of security relevant events:– “Someone is trying to log in as you”

• User needs to accept notifications• Notifications no 100% reliable• Not “out of band” (can be faked, intercepted)• Safari Notifications may be useful for one time

passwords (OTP)

Can I use it?

http://caniuse.com/#feat=notifications

Encryption

• Client side encryption• Allows encryption of specific sensitive fields

(e.g. payment data, passwords)• Intermediate services (proxies, web services)

don’t need to know the information• Upcoming: CryptoAPI (June 2013)

http://www.w3.org/TR/WebCryptoAPI/• Until then: https://www.pidder.de/pidcrypt/

Client side password hashing

• Server sends random “nonce” as part of login form.

• Client calculates hash from password/nonce• Passes hash to server• Server verifies hash• Advantage: Server never gets to know the

“real” password.

Signup

• Use enters password• Client hashes password• Password hash transmitted to server• Salt: Username? Provided by server?• Changing password: Same procedure, salt may

change.

Summary

• Lots of cool and useful tools in HTML5• Use them as appropriate• “HTML5” itself isn’t the risk. Bad coding is the

risk• Understand privacy issues• Understand user behavior• Share your code an experiences (OWASP!!)

Thanks!

! Thanks !Questions?jullrich@sans.edu

http://authonthemove.comhttp://isc.sans.edu

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