Security Best Practices for Mobile Development

Security Best Practices for Mobile

Development

Developer Track

Tom Gersic, Model Metrics�/ Salesforce.com

Director, Technical Solutions

Twitter: @tomgersic

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All about Model Metrics

Now a Salesforce.com Company

10 year track record - 2,000+ cloud engagements

Passionate & innovative World-class skills - CRM,

Force.com, Heroku, Radian6, Rypple, iOS and Android

In-house design studio – ModelFX

Mobile experts - iPhone, iPad and Android

Agenda

1. Fundamental Principles

2. What iOS and Android Share

3. iOS Specific Characteristics

4. Android Specific Characteristics

5. Salesforce Mobile Offerings

Throwing down the gauntlet…

Rules

1. Don’t break the phone or do

anything that might break it.

2. You need to be done before

Q&A starts.

3. If you are successful, you need

to tell us how you did it.

Who thinks the data on their phone is secure?

Welcome to Dreamforce 20.12 LTS (GNU)

Last login: Fri Sep 02 12:00:00 2011 from nat-

204-14-239-209-sfo.net.salesforce.com

@tomgersic:~$ FUNDAMENTAL SECURITY PRINCIPLES

Vulnerability

Threat

Consequence

Mitigation

Separation of Concerns – Principle of Least Privilege

Security Stack





@tomgersic:~$ WHAT iOS AND ANDROID SHARE






device security

Mobile Device Management Providers

http://bit.ly/magicmdm

MDM Compliance






device security

OS / data security

Data Security – Hardware Encryption

Requires PIN/Passcode on both iOS and Android

Supported on

iPhone 3GS w/ iOS v4+ (AES 256 bit)

Android Honeycomb+ (AES 128 bit)

• Some manufacturers increase to AES 256 bit (Samsung SAFE)

SD Card encryption on Android is manufacturer specific.





device security

OS / data security

OS / application security

Application Sandboxing

Application Signing

In-App Encryption

ASLR (PIE) and DEP

nat-204-14-239-209-sfo.net.salesforce.com



device security

OS / data security


@tomgersic:~$ iOS SPECIFIC CHARACTERISTICS



device security

OS / data security



known historical exploits

Libtiff Image Exploit / Jailbreak

• iPhone 1 – patched in 1.1.2

• Tiff buffer overflow

• No DEP/ASLR – nothing to prevent executing code on the

heap

• Gained root access from viewing an image on the web

Concatenated SMS Exploit – Charlie Miller

Concatenated SMS Exploit

• Takes 519 SMS messages – all but 1 is invisible

• Send message -1 of X to underflow the array buffer

• Can’t be stopped by the user

• Used to write an entire binary executable to the heap, and run

it, taking over the phone.



device security

OS / data security




application sandbox

Stripped down OS

• Unix/BSD based OS, but…

• No shell (/bin/sh).

• No typical Unix utilities like ls, rm, cd, ps, etc.

• All public apps reviewed.

• Private “Enterprise” apps contractually limited to internal

organization.

iOS Sandbox Specifics

• All apps (Apple’s and App Store) run as “mobile” user.

• Sandboxing is bolted on -- handled via XNU Sandbox

“Seatbelt” kernel extension.

• Applications run in separate subdirectories of

/private/var/mobile/Applications

• Any app in this directory is loaded with “container”

(sandboxed) profile.

Platform Apps

• Some platform apps, like Mobile Safari run with a sandbox

profile as well.

Limited Background Processing

Unlimited:

Audio Streaming (Spotify, Pandora)

GPS / Navigation

VOIP

Newsstand app content downloading

Hardware integrations (bluetooth, other external accessories)

Everything else: 10 minute window after app closes to finish any

task.



device security

OS / data security




application sandbox

hardware encryption

Hardware Encryption

• Everything is encrypted, right?

Hardware Encryption

• With a PIN/Passcode, Email, Attachments, and some other

system files are encrypted while device is locked

• Any other app is storing the keys with the lock unless app

specifies NSFileProtectionComplete


device security

OS / data security




application sandbox

hardware encryption

simple hacking – no jailbreak required

Facebook

My Secret Apps

My Secret Apps

device security

OS / data security




application sandbox

hardware encryption


jailbreak

data security

network security

application security



application sandbox

hardware encryption


jailbreak

mitigation

Application Encryption

• Encrypt your data yourself using PIN / Passcode

• CoreData/SQLCipher

NSIncrementalStore

Good Dynamics

• FMDB/SQLCipher

Salesforce Smartstore

Jailbreak Detection

• Sandbox integrity check: fork() should fail

• Check for jailbreak files:

/Applications/Cydia.app

/Library/MobileSubstrate/MobileSubstrate.dylib

/var/cache/apt

/bin/sh

/bin/bash

Enable ASLR in your app

• ASLR: Address Space Layout Randomization

Stack Canaries

• AKA Stack Smashing Protection

• Protect against buffer overflows

• Places random known value (canary) before local variables

• Use Apple LLVM – won’t work with LLVM GCC

Hide Data from App Snapshot Images

application security



application sandbox

hardware encryption


jailbreak

mitigation

@tomgersic:~$ ANDROID SPECIFIC CHARACTERISTICS



application sandbox

hardware encryption


jailbreak

mitigation


newsworthy exploits

NFC Exploit

DroidDream Malware



application sandbox

hardware encryption


jailbreak

mitigation


newsworthy exploits

android sandbox

Android Sandbox

Permissions

Background Processes / App Interaction

The Return of Separation of Concerns and the

Principle of Least Privilege

Types of Android Components

Activities

Intent

Service

Content Provider

Broadcast Receiver

Public / Private Components

But what about custom keyboards?

Keyboard Security Risks

Except Passwords?

https://github.com/tomgersic/AndroidKeyLogger


application sandbox

hardware encryption


jailbreak

mitigation


newsworthy exploits

android sandbox

@tomgersic:~$ Salesforce SmartStore

Force.com Mobile SDK

https://github.com/forcedotcom

https://github.com/forcedotcom

Salesforce.com Mobile SDK SmartStore

• SQLite ORM wrapper for Native and Hybrid apps built on the

SFDC Mobile SDK

• NoSQL style JSON-based document store

SmartStore Stack

SmartStore PIN

Who STILL thinks the data on their phone is secure?

Tom Gersic

Director, Technical Solutions

@tomgersic

Documents

Security Best Practices for Mobile Development