data transfer security for mobile apps

Data transfer security for mobile apps

what the fish doesn’t notice in the ocean? 🐟

#mddaylviv2015 @vixentael

There ain’t enough talks about security

Apple Security GuideEvery program is a potential target.

Your customers’ property and your reputation

are at stake.

https://developer.apple.com/library/mac/documentation/Security/Conceptual/SecureCodingGuide/Introduction.html

data transfer security for mobile apps #mddaylviv2015 @vixentael

https://developer.apple.com/library/mac/documentation/Security/Conceptual/SecureCodingGuide/Introduction.html

3 kinds of data to protect

Data in storage

Data in memory

Data in motion


Data in motion: what could possibly go wrong

Communication with server. Usually.


Imagine little fish...


...in the ocean of threats

active eavesdropping

data leakage

evil twin

replay attack

...in the ocean of threats

* SSL experimenting with Android Top100 apps http://bit.ly/1NqpheM

* Intercepting the App Store's Traffic on iOS http://bit.ly/1H3xMrs

One proxy to rule ‘em all!

http://bit.ly/1NqpheM

http://bit.ly/1H3xMrs

Attack reasonsMany apps use HTTP*


*iOS9 ATS will decrease this number


Some apps use HTTPS




Some apps use HTTPS

Few apps encrypt user’s data



Why is this happening?

1. Security is hard.

STACKOVERFLOW!

Let’s StackOverflow!http://stackoverflow.com/a/21826729


http://stackoverflow.com/a/21826729

Weird paddinghttp://stackoverflow.com/a/21826729



2. Software is buggy

Remove padding!




Omg WTF is going on

WTFhttp://stackoverflow.com/a/26147479

WTF WTF



3. Illusion of safety is still a illusion


#define kUserPassword @“1111111”

Armoring your fish

Realize security risks


Amateurs Produce Amateur Cryptography

Anyone can invent a security system

that he himself cannot break

— Schneier's Lawhttps://www.schneier.com/blog/archives/

2011/04/schneiers_law.html


https://www.schneier.com/blog/archives/2011/04/schneiers_law.html

Do not re-implement existing things


Security is a system, not a pluggable library

Build stout architecture


Build stout architecture

cryptolib

key management


Use great tools

Themis https://github.com/cossacklabs/themis

RNCryptor https://github.com/RNCryptor/RNCryptor

MIHCrypto https://github.com/hohl/MIHCrypto

OTRKit https://github.com/ChatSecure/OTRKit

libsodium/NaCL https://github.com/mochtu/libsodium-ios

scientific background trust big guys good track record


https://github.com/cossacklabs/themis

https://github.com/RNCryptor/RNCryptor

https://github.com/hohl/MIHCrypto

https://github.com/ChatSecure/OTRKit

https://github.com/mochtu/libsodium-ios

Use SSL? Do it right!

https://www.owasp.org/index.php/Transport_Layer_Protection_Cheat_Sheet

✤use long keys

✤remove backward compatibility

✤use good ciphers (EC vs RSA)

✤SSL pinning✤use cheat sheet

https://www.cossacklabs.com/avoid-ssl-for-your-next-app.htmlSSL has a lot of problems

To survive you need to:


https://www.owasp.org/index.php/Transport_Layer_Protection_Cheat_Sheet

https://www.cossacklabs.com/avoid-ssl-for-your-next-app.html

TLS/SSL in short


Where can it break?


SSL pinning


SSL pinning on iOS

https://possiblemobile.com/2013/03/ssl-pinning-for-increased-app-security/ https://www.paypal-engineering.com/2015/10/14/key-pinning-in-mobile-

applications/

- (void)connection:(NSURLConnection *)connection willSendRequestForAuthenticationChallenge:(NSURLAuthenticationChallenge *)challenge { SecTrustRef serverTrust = challenge.protectionSpace.serverTrust; id<NSURLAuthenticationChallengeSender> sender = challenge.sender; SecCertificateRef certificate = SecTrustGetCertificateAtIndex(serverTrust, 0); NSData * remoteCertificateData = CFBridgingRelease(SecCertificateCopyData(certificate)); NSString * cerPath = [[NSBundle mainBundle] pathForResource:@"MyLocalCertificate" ofType:@"cer"]; NSData * localCertData = [NSData dataWithContentsOfFile:cerPath]; if ([remoteCertificateData isEqualToData:localCertData]) { NSURLCredential * credential = [NSURLCredential credentialForTrust:serverTrust]; [sender useCredential:credential forAuthenticationChallenge:challenge]; } else { [sender cancelAuthenticationChallenge:challenge]; } }


https://possiblemobile.com/2013/03/ssl-pinning-for-increased-app-security/

https://www.paypal-engineering.com/2015/10/14/key-pinning-in-mobile-applications/

SSL pinning more easy :)Swift lib for HTTPS with SSL pinning https://github.com/johnlui/Pitaya/wiki

let certData = NSData(contentsOfFile:

NSBundle.mainBundle().pathForResource("lvwenhancom", ofType: "cer")!)!... ....addSSLPinning(LocalCertData: certData) { () -‐> Void in print("Under Man-‐in-‐the-‐middle attack!")}


https://github.com/johnlui/Pitaya/wiki

How to achieve the solution

Let’s imagine chatting app

simple API

authentication meaningfull communication

confidentiality thread


Securing app step by step1. HTTPS everywhere

2. SSL pinning

3. Encrypt messages by persistent keys


Securing app step by step1. HTTPS everywhere

----> SSL/TLS has lots of bugs and bad crypto

2. SSL pinning

----> is not a panacea

3. Encrypt messages by persistent keys

----> can be easily cracked


Securing in a more proper way

perfect forward secrecy

use good ciphers


Using ephemeral key


How to achieve it easilyhttps://github.com/cossacklabs/themis

1. establish session

2. encrypt message with SecureSession before sending

3. decrypt message after receive

4. encrypt history with SecureCell


https://github.com/cossacklabs/themis

How to achieve it easily

https://github.com/cossacklabs/mobile-websocket-example


https://github.com/cossacklabs/mobile-websocket-example

Security is hard, but if you’re smart, security is not so hard :)

The last slide

@vixentael iOS developer

at stanfy.com [creating awesome mobile

and IoT apps]

http://www.stanfy.com

To read★ CryptoCat iOS app security audit

https://nabla-c0d3.github.io/documents/iSEC_Cryptocat_iOS.pdf

★ Why you should avoid SSL for your next application

https://www.cossacklabs.com/avoid-ssl-for-your-next-app.html

★ OAuth1, OAuth2, OAuth...?

http://homakov.blogspot.com/2013/03/oauth1-oauth2-oauth.html

https://nabla-c0d3.github.io/documents/iSEC_Cryptocat_iOS.pdf

http://homakov.blogspot.com/2013/03/oauth1-oauth2-oauth.html

To watch youtube★ All tasks of Moxie Marlinspike

https://www.youtube.com/watch?v=ibF36Yyeehw

https://www.youtube.com/watch?v=8N4sb-SEpcg

https://www.youtube.com/watch?v=tOMiAeRwpPA

https://www.youtube.com/watch?v=ibF36Yyeehw

https://www.youtube.com/watch?v=8N4sb-SEpcg

https://www.youtube.com/watch?v=tOMiAeRwpPA

To read more slides★ Securing iOS apps

https://speakerdeck.com/mbazaliy/securing-ios-applications

★ Users' data security in iOS applications

https://speakerdeck.com/vixentael/users-data-security-in-ios-applications

★ Reversing 101

https://speakerdeck.com/0xc010d/reversing-101

https://speakerdeck.com/0xc010d/reversing-101

data transfer security for mobile apps

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