Mobile Handsets: A Panoramic Overview

Adam C. Champion and Dong Xuan Department of Computer Science & Engineering

The Ohio State University Autumn 2012

Outline

•  Introduction •  Mobile Handset Architecture •  Mobile Handset Operating Systems •  Networking •  Applications •  Mobile Handset Security

Mobile Handset Definition •  Mobile handsets (mobiles):

electronic devices that provide services to users: –  Internet –  Games –  Contacts

•  Form factors: tablets, smartphones, consoles

•  Mobile: arguably, your next computer system

Mobile Handsets: Business

•  Meteoric sales and growth: – ≥ 5 billion mobile phone subscriptions worldwide – Some people have multiple phones! – Mobile handsets & industries: $5 trillion [3]

•  Mobile phones are replaced every 6 months in S. Korea (just phones) [4]

•  We can’t ignore these numbers •  Note: mobiles are computer systems

What’s Inside a Mobile Handset?

Source: [5]

Handset Architecture (1)

•  Handsets use several hardware components: –  Microprocessor –  ROM –  RAM –  Digital signal processor –  Radio module –  Microphone and speaker –  Hardware interfaces –  LCD display

Handset Architecture (2)

•  Handsets store system data in electronically-erasable programmable read-only memory (EEPROM) – Mobile operators can reprogram phones without

physical access to memory chips •  OS is stored in ROM (nonvolatile memory) •  Most handsets also include subscriber identity

module (SIM) cards

Handset Microprocessors

•  Handsets use embedded processors –  Intel, ARM architectures dominate market.

Examples include: •  BlackBerry 8700, uses Intel PXA901 chip [6] •  iPhone 3G, uses Samsung ARM 1100 chip [7]

– Low power use and code size are crucial [5] – Microprocessor vendors often package all the

chip’s functionality in a single chip (package-on-package (PoP)) for maximum flexibility

– Apple A4 uses a PoP design [10]

Example: iPhone 3G CPU •  The iPhone: a real-world

MH [7–9] –  Runs on Samsung S3C6400

chip, supports ARM architecture

–  Highly modular architecture

Source: [8]

Mobile Handset OSes (1) •  Key mobile OSes: –  Google Android –  Apple iOS –  BlackBerry OS –  Windows Phone 7

(formerly Windows Mobile)

•  Others include: –  Symbian OS –  HP Palm webOS –  Samsung bada

U.S. market share. Source: [25]

Mobile Handset OSes (2) •  Symbian OS (ARM only)

–  Closed-source (Nokia/Accenture) –  Multitasking –  Programming: C++, Java ME,

Python •  BlackBerry OS (?)

–  Proprietary (RIM) –  Multitasking –  Many enterprise features –  Programming: Java ME

•  iOS (ARM only) –  Proprietary (Apple) –  Multitasking –  Multi-touch interface –  Programming: Objective-C

•  Windows Phone 7/8 (ARM only) –  Proprietary (Microsoft) –  No multitasking –  Programming: Silverlight,

XNA, .NET Compact Framework, native C/C++ (WP8)

•  Android (ARM, x86, …) –  Open-source –  Multitasking –  Programming: Java

(Apache Harmony) •  Other OS features

–  Most require app code signing –  Many support Adobe Flash Lite,

multitasking –  ARM is predominant ISA

Mobile Handset Networking

•  Handsets communicate with each other and with service providers via many networking technologies

•  Two “classes” of these technologies: – Cellular telephony – Wireless networking

•  Most handsets support both, some also support physical connections such as USB

Cellular Telephony Basics (1) •  Many mobile handsets

support cellular services •  Cellular telephony is radio-

based technology, radio waves propagated by antennas

•  Most cellular frequency bands: 800, 850, 900, 1800, 1900, 2100 MHz

Source: [5]

Cellular Telephony Basics (2)

•  Cells, base stations –  Space divided into cells, each

has base station (tower, radio equipment)

–  Base stations coordinate so mobile users can access network

–  Move from one cell to another: handoff

Cellular Telephony Basics (3) •  Statistical multiplexing –  Time Division Multiple Access (TDMA)

•  Time & frequency band split into time slots •  Each conversation gets the radio a fraction of the time

–  Frequency Division Multiple Access (FDMA) analogous

Wireless Networking (1)

•  Bluetooth (BT) –  Frequency-hopping radio technology: hops among

frequencies in 2.4 GHz band – Nearly ubiquitous on mobile handsets –  Personal area networking: master device associate with ≤ 7 slave devices (piconet)

–  Pull model, not push model: •  Master device publishes services •  BT devices inquire for nearby devices, discover published

services, connect to them – Latest version: 4.0; latest mobiles 3.0, 4.0 [12]

Wireless Networking (2)

•  WiFi (IEEE 802.11) – Variants: 802.11b, g, n, etc. – Radio technology for WLANs: 2.4, 3.6, 5 GHz –  Some mobile handsets support WiFi, esp. premium

ones! – Two modes: infrastructure and ad hoc

•  Infrastructure: mobile stations communicate with deployed base stations, e.g., OSU Wireless

•  Ad hoc: mobile stations communicate with each other without infrastructure

– Most mobiles support infrastructure mode

Mobile Handset Applications •  Mobile apps span many categories, e.g.: – Games: Angry Birds, Assassin’s Creed, etc. – Multimedia: Pandora, Guitar Hero, etc. – Utilities: e-readers, password storage, etc.

•  Many apps are natively developed for one mobile OS, e.g., iOS, Android – Cross-platform native mobile apps can be developed

via middleware, e.g., Rhodes [13], Titanium [14] – Can also build (HTML5) Web apps, e.g., Ibis Reader

[15], Orbium [16] •  We’ll discuss mobile app development next

Native Mobile App Development

•  Mobile apps can be developed natively for particular mobile handset OSes –  iOS: Xcode/Interface Builder; Mac only – Android: Eclipse; Windows/Mac/Linux – Windows Phone: Silverlight, XNA, Visual Studio

2010+; Windows only – Symbian: Eclipse, NetBeans; Windows only – BlackBerry: Eclipse, Visual Studio; Windows only

Other Mobile App Development

•  Middleware – Rhodes: Ruby/HTML compiled for all mobile OSes – Titanium: HTML/JS + APIs compiled for iOS,

Android –  Still dependent on native SDK restrictions

•  Web development: HTML5, CSS, JS – Works on most mobile browsers – Can develop on many IDEs, Win/Mac/Linux

•  SMS/cellular promotions

Business Opportunities •  Virtually every mobile OS supports app sales via stores, e.g.,

iOS App Store, Google Play (Android Market), MS App Hub •  Devs sign up for accounts, download SDKs

–  Costs: $99/yr (iOS, App Hub), $25 once (Google Play) –  http://create.msdn.com/, http://developer.apple.com, http://play.google.com

Mobile Handset Security Issues •  People store much info on their mobiles •  “Smartphones are the new computers.…2 billion…

will be deployed by 2013” – M.A.D. Partners [18] •  Handsets are targets for miscreants: – Calls –  SMS/MMS messages – E-mail – Multimedia – Calendars – Contacts –  Phone billing system [18]

Handset Malware History (1)

•  Hackers are already attacking handsets – Most well-known case: a 17-year-old broke into

Paris Hilton’s Sidekick handset [19] – Less well-known: worms, viruses, and Trojans

have targeted handsets since 2004 •  2004: [20]

–  Cabir worm released by “29A,” targets Symbian phones via Bluetooth

– Duts virus targets Windows Mobile phones –  Brador Trojan opens backdoor on Windows Mobile [24]

Handset Malware History (2) •  2005: [21]

–  CommWarrior worm released; replicates via Bluetooth, MMS to all contacts –  Doomboot Trojan released; claims to be “Doom 2” video game, installs Cabir and

CommWarrior •  2006: [20, 21]

–  RedBrowser Trojan released; claims to be a Java program, secretly sends premium-rate SMS messages to a Russian phone number

–  FlexiSpy spyware released; sends log of phone calls, copies of SMS/MMS messages to Internet server for third party to view

•  2008: [22] –  First iPhone Trojan released

•  2009–2010: iPhone “Rickrolling”, Android SMS malware, etc. •  “The single biggest thing threatening any enterprise today on a security

basis is mobile. Furthermore, mobile phone application stores are the greatest malware delivery system ever invented by man” – Robert Smith, CTO, M.A.D. Partners [18]

Key Handset Threats, Attacks •  Info theft [23] –  Transient info: user location –  Static info: bluesnarfing attacks, WEP & WPA cracks [24]

•  Service/$ theft, e.g., premium-rate calls/SMS [23] •  Denial-of-service attacks [23] –  Flooding attacks overload handset radio with garbage –  Power-draining attacks attempt to drain battery

•  Botnets and DoS attacks against networks [22] •  Exploiting the human factor (see HW 1) •  We’ll discuss risk management strategies

Risk Management Strategies

•  Organizations must: – Understand rapidly-evolving threatspace [18] – Understand applicable laws & regulations – Understand employee demand for handsets and

balance this against the risk they pose –  Institute CSO policies to achieve compliance

(and get top management on board!) –  Inform employees about policies (change mgmt) –  Implement the policies with tech and people

Risk Management Tactics •  To implement strategies, organizations must: – Decide whether to distribute handsets to employees for

business purposes, allow use – Encrypt device data – Remote data wipe as needed –  Procure, install anti-malware, firewall products – Require VPN use, strong passwords, inventory mgmt. – Monitor employee handset use to detect attacks – Educate employees about the threatspace, train them to

treat handsets as any other computer system –  Prevent, detect, and respond appropriately

Discussion and Questions

Thank you

References [1] 1.  Wireless Intelligence, “Snapshot: Global mobile connections surpass 5 billion milestone,” 8

Jul. 2010, https://www.wirelessintelligence.com/print/snapshot/ 100708.pdf

2.  T. T. Ahonen, “5 - 4 - 3 - 2 - 1, as in Billions. What do these gigantic numbers mean?,” 6 Aug. 2010, http://communities-dominate.blogs.com

3.  T. T. Ahonen, 29 Sep. 2010, http://untether.tv/ellb/?p=2227 4.  T. T. Ahonen, “When there is a mobile phone for half the planet: Understanding the biggest

technology”, 16 Jan. 2008, http://communities-dominate.blogs.com/ brands/2008/01/when-there-is-a.html

5.  J. L. Hennessy and D. A. Patterson, Computer Architecture: A Quantitative Approach, 4th ed., Elsevier, 2007

6.  Research in Motion, “BlackBerry 8700c Technical Specifications”, http://www.blackberry.com/products/pdfs/blackberry8700c_ent.pdf

7.  R. Block, “iPhone processor found: 620MHz ARM CPU”, Engadget, 1 Jul. 2007, http://www.engadget.com/2007/07/01/iphone-processor-found-620mhz-arm/

8.  Samsung Semiconductor, “Product Technical Brief: S3C6400, Jun. 2007”, http://www.samsung.com/global/system/business/semiconductor/product/2007/8/21/661267ptb_s3c6400_rev15.pdf

References [2] 9.  Wikipedia, “iPhone”, updated 15 Nov. 2008, http://en.wikipedia.org/wiki/Iphone 10.  Wikipedia, “Apple A4”, updated 21 Oct. 2010, http://en.wikipedia.org/wiki/

Apple_A4 11.  Gartner (12 August 2010). "Gartner Says Worldwide Mobile Device Sales Grew 13.8

Percent in Second Quarter of 2010, But Competition Drove Prices Down". Press release. http://www.gartner.com/it/page.jsp?id=1421013

12.  Wikipedia, “Samsung Galaxy S”, updated 21 Oct. 2010, http://en.wikipedia.org/ wiki/Samsung_Galaxy_S

13.  Rhomobile Inc., http://rhomobile.com/ 14.  Appcelerator Inc., http://www.appcelerator.com/ 15.  Ibis Reader LLC, http://ibisreader.com 16.  Björn Nilsson, Orbium, http://jsway.se/m/ 17.  Ericsson.Global mobile data traffic nearly triples in 1 year, 12 August 2010.

http://www.ericsson.com/thecompany/press/releases/2010/08/1437680. 18.  Georgia Tech Information Security Center, “Emerging Cyber Threat Reports 2011,”

http://www.gtisc.gatech.edu/pdf/cyberThreatReport2011.pdf

References [3] 19.  B. Krebs, “Teen Pleads Guilty to Hacking Paris Hilton’s Phone”, Washington Post, 13 Sep.

2005, http://www.washingtonpost.com/wp-dyn/content/article/2005/09/ 13/AR2005091301423_pf.html

20.  D. Emm, “Mobile malware – new avenues”, Network Security, 2006:11, Nov. 2006, pp. 4–6 21.  M. Hypponen, “Malware Goes Mobile”, Scientific American, Nov. 2006, pp. 70–77,

http://www.cs.virginia.edu/~robins/Malware_Goes_Mobile.pdf 22.  PandaLabs, “PandaLabs Quarterly Report: January–March 2008”,

http://pandalabs.pandasecurity.com/blogs/images/PandaLabs/2008/04/01/Quarterly_Report_PandaLabs_Q1_2008.pdf

23.  D. Dagon et al., “Mobile Phones as Computing Devices: The Viruses are Coming!”, IEEE Pervasive Computing, Oct. – Dec. 2004, pp. 11–15

24.  G. Fleishman, “Battered, but not broken: understanding the WPA crack”, Ars Technica, 6 Nov. 2008, http://arstechnica.com/articles/paedia/wpa-cracked.ars

25.  Nielsen Co., “Smartphones Account for Half of all Mobile Phones, Dominate New Phone Purchases in the US”, 26 Mar. 2012, http://blog.nielsen.com/nielsenwire/online_mobile/ smartphones-account-for-half-of-all-mobile-phones-dominate-new-phone-purchases-in-the-us