Practicing Safe Script

Front End Web Security is hard. This deck goes through why there's no hope of patching every hole and suggests the opposite approach via whitelisting (old news, right?). Also suggests we try to make security sexier so more people buy-in.

1. Practicing Safe Script Alex Sexton
2. I work at .
3. which is in . California
4. but…
5. I live in . Texas
6. The web has a lot in common with Texas.
7. “The wild west.”
8. In 1985, Texas had a problem.
10. Littering
11. Some Texans defended their “God-given right to litter.”
12. ಠ_ಠ
13. There were fines for littering.
14. photo by Curtis Gregory Perry
15. But no one seemed to care.
16. The state tried some slogans.
18. But these slogans apparently did not resonate with the core offenders
19. Males 18-24 “Bubbas in Pickup Trucks”
20. In 1985 Texas tried a new campaign:
22. The campaign reduced litter on Texas highways ! 72% ! from 1986 to 1990.
23. My point is…
24. “Hey everyone, you should make your websites more secure because it’s important.” ! Probably isn’t going to do the trick.
25. DON’T! MESS! WITH! XSS Also probably won’t work.
26. Web developers, not security researchers, are the core audience.
27. Web security is hard.
28. “All you have to do is never make a single mistake.” - I Think Mike West
29. “I discount the probability of perfection.” - Alex Russell
30. Content Injection
34. Everyone has a friend that always seems to pick “<script>alert(‘hacked!’);</script>”   as their username.
35. My User Agent
36. My Friend, Mike Taylor’s User Agent Mozilla/5.0  (Macintosh;  Intel  Mac  OS  X  10.9;   rv:25.0)  <script>alert(‘lol’);</script>  Gecko/20100101   Firefox/25.0
37. My Friend, Mike Taylor’s User Agent Mozilla/5.0  (Macintosh;  Intel  Mac  OS  X  10.9;   rv:25.0)  <script>alert(‘lol’);</script>  Gecko/20100101   Firefox/25.0
38. ಠ_ಠ
39. Samy
43. ಠ_ಠ
44. So let’s just detect malicious scripts!
46. alert(1)
47. The Billy Hoffman Whitespace Attack <script>   ! </script>
48. The Billy Hoffman Whitespace Attack <script>   ! </script> Malicious Code
49. The Billy Hoffman Whitespace Attack <script>   ! </script> tab tab tab space space
50. The Billy Hoffman Whitespace Attack <script>   ! </script> 1 1 1 0 0
51. You cannot detect malicious code.
52. output.replace(/<script>/, ‘’);
53. CSS Hacks
54. Old School
56. Link Visited Link getComputedStyle( getComputedStyle( ) ) === \o\|o|/o/ Pretty much People Celebrating (or screaming on fire)
57. Timing Attacks
58. Security by Inaccuracy
59. requestAnimationFrame + :visited = ಠ_ಠ
60. requestAnimationFrame + :visited = ಠ_ಠ
61. requestAnimationFrame + :visited = ಠ_ಠ
62. Link Visited Link
63. Link Visited Link <16ms >60ms Time to render
64. Set-Cookie ‘csrf=0003’
68. It gets worse.
69. Contextis White Paper
70. Cross-Domain Data Snooping via SVG Filters and OCR
72. ಠ_ಠ
73. We need a new approach.
74. Content Security Policy
76. Disallow Inline JS, CSS By Default!
77. Disallow eval By Default!
78. Disallow Cross Domain JS, CSS, IMG, Fonts
79. Report Violations!
81. A White List That’s the key!
82. Good Security Goes Beyond Content Injection
83. <iframe sandbox>
84. HTTPS Everywhere
85. HTTPS Everywhere
86. HTTPS Only
87. 301 Redirect http
88. https HSTS
89. Frame Busting
90. Disallow as an iFrame X-Frame-Options
91. It’s “security by default.” At least much closer…
92. You can rely a little less on being perfect.
93. it only matters if everyone buys in. But
94. We need our own slogan.
95. We need developers to take pride in making secure applications.
96. Don’t Mess With The Web
97. ಠ_ಠ
98. Let’s do something about it together.
99. Thanks! @SlexAxton Special Thanks To: Mike West * 1000 Adam Baldwin Contextis MDN