SSL, CAs and keeping your stuff safe
BQSFTFOUBUJPOCZBSNJOSPOBDIFSGPSQZHSVOO
http://lucumr.pocoo.org/ — @mitsuhiko
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SSL, CAs and keeping your stuff safe
BQSFTFOUBUJPOCZBSNJOSPOBDIFSGPSQZHSVOO
http://lucumr.pocoo.org/ — @mitsuhiko
a capitalistic and system conformant talk about encryption
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Armin Ronacher
Independent Contractor for Splash Damage / Fireteam
Doing Online Infrastructure for Computer Games
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… The Problem with Programmers
~ Epilogue ~
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Programmers think everything
is a technical problem
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Fraud
~ Chapter 1 ~
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XXXX-XXXX-XXXX-1234
What is the worst that can happen?
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What makes Credit Card Numbers “secure”?
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theft
ere will always be criminals
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prevented
But what damage can they do?
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Bitcoin A Credit Card
Strong Encryption Potentially No Encryption
256 bit private key 16 digit number + checksum
decentralized centralized
√ x
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But I'd rather lose my credit card …
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Never
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LOL
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We Accept Stolen Creditcards
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e Protocol
e Process
is insecure
is secure
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If the aud percentage is smaller than
the transaction fees we're all good.
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It's too easy to forget the
bigger picture
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of Lock Symbols and Encryption
~ Chapter 2 ~
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the lock symbol is a lie
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the lock stands for secure
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but so is encryption
8
7
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such security
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such buzzwords
CRIME
BEAST
Heartbleed
BREACH
PFS
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users need to understand how to
keep good om bad lock symbols /
good om bad encryption.
=
-
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but even developers are not sure yet …
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remember why you encrypt
(NSA
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Why do we Encrypt Traffic?
~ Chapter 3 ~
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No content
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public WiFi the unencrypted browser session
kilLed
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?
Who is the Attacker?
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om secret agents to idiots
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om targeted to untargeted
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om low to high probability
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What You Need for Encryption
~ Chapter 4 ~
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passive vs active eavesdropping
encryption authentication
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$ ssh pocoo.org
The authenticity of host 'pocoo.org (148.251.50.164)' can't be established.
RSA key fingerprint is 14:23:83:02:45:f9:9c:d0:eb:39:c7:14:42:f5:9f:9c.
Are you sure you want to continue connecting (yes/no)?
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your user does not check ngerprints
(your
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e
Certificate Authorities
thus:
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CAs are worthless for securing APIs
let it be known that
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Protecting APIs and Services
~ Chapter 5 ~
(non
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The Only Rule to Follow
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run your own CA
issue certi cates for 24 hours
trust your own CA only
screw re ocations
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You trust your own CA by
distributing the certi cate to
everybody.
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If your root gets compromised,
distribute new root certi cates.
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If an individual key gets compromised,
in less than 24 hours everything is ne.
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from requests import get
resp = get('https://api.yourserver.com/',
verify='your/certificate.bundle')
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“But my awesome AntiVirus says
your certi cate is not trusted.”
— Windows User
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Certificate Authorities Again
~ Chapter 6 ~
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Hardly news: CAs are Broken
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But why are the broken?
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I Trust “TÜRKTRUST Elektronik Serti ka Hizmet
Sağlayıcısı” to ouch for the identity of any domain on
the planet.
Trusting a CA:
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trusting half the world: one shitty employee in one shitty
CA is enough to break your security.
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I Trust “Comodo” to ouch for the identity of “Foo
Owner” foo.com.
I only trust “Foo Owner” to ouch for the identity of
api.foo.com
What we actually want:
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if you have seen google.com being from Verisign and all
the sudden google.com becomes a StartSSL certificate you
know something might be wrong.
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Soon: Certificate Pinning?
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Frack OpenSSL and Question “Best Practices”
~ Chapter 7 ~
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Self-Signed Certificates are not bad. Just in browsers.
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Never. Ever. Look at OpenSSL's Source.
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OpenSSL's "patches" are even worse:
Apple's OpenSSL always trusts system store :-/
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Requests by default trusts it's own bundle :-/
(And does not even properly document how to use custom ones)
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With Heartbleed SSL was less secure than no SSL :-/
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Growing SSL
~ Chapter 8 ~
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Credit Cards were made for thousands of people
Certificate Authorities were made for hundreds of sites
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OpenSSL was probably improperly audited
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See “OpenSSL Valhalla Rampage” :-(
“i give up. reuse problem is unixable.
dlg says puppet crashes”
— tedu
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Plan for Failure
~ Chapter 9 ~
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what
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what happens to your user if he gets hacked?
(food for thought: keyloggers are still a thing)
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what happens to your data
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what happens to your company
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encryption is hardened security
it must not be your only defense
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?
Feel Free To Ask Questions
Talk slides will be online on lucumr.pocoo.org/talks
You can find me on Twitter: @mitsuhiko
And gittip: gittip.com/mitsuhiko
Or hire me: armin.ronacher@active-4.com