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Mobile Systems

Updated Jan 30, 2024 ·

Overview​

Mobile Device Wireless Communications:

  • GPS (Global Positioning Systems) - Uses satellites to track where an object is
  • Infrared - Legacy, line-of-sight wireless communications
  • Cellular - Phone calls or SMS/text messages
  • WIFI
  • Bluetooth
  • Near Field Communication (NFC)

Technology​

GPS​

GPS (Global Positioning System) is a satellite-based navigation system that provides precise location and time information to users worldwide. It consists of a network of satellites orbiting the Earth and user receivers that calculate their position using signals from these satellites.

  • Widely used for navigation, mapping, location-based services, and precise timing applications.
  • Devices receive signals from multiple satellites to calculate their position using trilateration.
  • Trilateration: Measures distance to at least four satellites to determine latitude, longitude, altitude, and time.

Security Implications:

  • Spoofing: Signals can be spoofed, leading to false location information.
  • Jamming: Deliberate interference can disrupt GPS signals, affecting navigation and timing.
  • Privacy Concerns: Location data from GPS can be exploited for surveillance or tracking purposes.
  • Cyberattacks: Vulnerabilities in GPS infrastructure could be exploited for cyberattacks on critical systems or infrastructure.
  • Dependency: Reliance on GPS for critical functions can pose risks if the system becomes unavailable or inaccurate.

Cellular 4G​

4G is a wireless communication standard that provides faster internet, better coverage, and lower delays than older generations.

  • Supports mobile apps on phones, tablets, and other devices
  • Uses LTE for high-speed data transfer
  • Enables smooth VoIP, video calls, and online streaming

4G uses radio frequencies for data transmission:

  • Narrowband

    • Short range
    • Suitable for low data and simple communication

  • Broadband

    • Longer range
    • Handles multiple high-speed data streams at once

While 4G improves performance, it also introduces new risks that must be managed:

  • Firmware Over-the-Air (OTA) Updates

    • Devices receive updates remotely without user action
    • If not properly secured, attackers could spoof or tamper with updates
    • Requires secure channels and digital signatures to verify update authenticity

Cellular 5G​

5G, or fifth-generation, cellular technology is the latest standard in wireless communication, succeeding 4G. 5G networks leverage advanced technologies such as millimeter-wave frequencies, massive MIMO (Multiple Input Multiple Output), and network slicing to deliver high-bandwidth, low-latency connectivity for a wide range of applications.

  • High data speeds, up to 10 Gbps.
  • Cells are smaller than 4G, meaning transmission range is up to 2km.
  • Base stations use fiber connections.
  • Requires 5G capable devices.

Security Implications of 5G:

  • Larger attack surface for cybercriminals to exploit.
  • User privacy and data protection concerns on massive data transmitted over 5G networks
  • Over-reliance on equipment from potentially untrusted vendors.

WiFi Direct​

WiFi Direct is a peer-to-peer wireless technology that allows devices to connect and communicate with each other directly, without the need for a traditional WiFi network or internet connection.

  • Useful for sharing files, streaming media, or playing multiplayer games
  • Does not use a wireless router, no internet connectivity.

VDI (Virtual Desktop Infrastructure)​

VDI (Virtual Desktop Infrastructure) allows users to access a virtual desktop that is hosted on company-owned infrastructure. This setup ensures:

  • Data stays within the company environment (not on the offshore user's device)
  • No need to issue physical hardware to offshore teams
  • Secure access to resources via controlled, isolated sessions

Mobile Device Tethering​

Mobile device tethering, also known as mobile hotspot or internet sharing, allows a smartphone or tablet to share its cellular data connection with other devices such as laptops, tablets, or gaming consoles.

  • Additional data usage charges from the mobile carrier may be incurred.
  • Battery life can also be easily drained.
  • Setting mobile device as a wireless hotspot
  • For wired connection, use USB Tethering or USB On-the-go (OTG)

Mobile Device Constraints​

  • Limited CPU and Battery

    • Limited power
    • Use lightweight cryptography like ECC
    • ECC uses a smaller key size
    • The more computations you do, the more you drain the battery

  • Limited transmission range

    • Affects wireless devices

  • Limited device access

    • Rooting - Breaking into android devices, to have full access or root access
    • Jailbreaking - Similar with rooting, but for Apple devices. See Mobile Vulnerabilities.

SIM Cards​

Subscribe Identity Modules (SIM) cards authenticates device to carrier network. It contains the following data:

  • Carrier subscription data
  • SIM Card serial number
  • Phone contacts (if not in the cloud)

Carrier Unlocking​

Carrier unlocking involves removing restrictions set by a carrier to allow the phone to be used on different networks.

  • Switching between mobile providers
  • Does not affect app installation or security controls

Mobile Security​

Mobile Security Controls​

Setting up solid security on mobile devices helps keep personal and sensitive data safe. Here are the key controls you should enable:

  • Access Control Mechanisms

    • Every mobile device should have passcodes or biometrics.
    • Passcodes: Default is often a 4-digit pin, but it's weak.
    • Strong Passwords: Use complex passwords like on computers.

  • Biometric Authentication

    • Some devices offer fingerprint or facial recognition to ease access.
    • Apple’s Touch ID: Common for iOS devices.
    • Android: Fingerprint options available but less common.

  • Encryption

    • Encrypt data on your device to protect it if lost or stolen.
    • iOS and Android: Enable encryption by setting a password.
    • Default since: Android Gingerbread and iOS 8.

  • Remote Wipe

    • Enable remote wiping to erase data if your device is lost.
    • Works if the device is connected to a network.
    • Available on both Android and iOS.

  • Screen Lock and Inactivity Timeout

    • Set your device to lock automatically after inactivity.
    • Limits access if the device is idle.
    • Locks out users after multiple incorrect passcode attempts.

  • Posture Checks

    • Checks device security before granting access.
    • Ensures devices meet compliance antivirus and patches.
    • Enforce patching and screen lock policies.
    • Confirms signatures and firewall settings.
    • If device fails checks, device is placed on a quarantine VLAN.
    • Quarantined device will be patched and then rechecked

Mobile Asset Deployments​

For more information, please see Mobile Asset Deployments.

  • Bring your own device (BYOD)

    • Employee uses personal device for work
    • IT department applies centralized policy

  • Choose your own device (CYOD)

    • Company offers a selection of devices
    • Employee can choose from these devices

  • Corporate-owned personally enabled (COPE)

    • Phone issued by the company
    • Can be used for work purposes, and for personal use
    • Device can be partitioned (containers) for personal and corporate apps

For more information, please see Mobile Assets Deployments.

Mobile Device Management​

Mobile Device Management (MDM) enables organizations to manage and secure mobile devices across various platforms (smartphones, tablets).

  • Enforces alphanumeric passcodes and encryption.
  • Disables unused features to enhance security.
  • Remote wipe functionality for lost or stolen devices.
  • Revokes access quickly when employees leave.
  • Disable a device's ability to sideload programs.
  • Detect if a device has been jailbroken or rooted.
  • Force each device to use a VPN connection.

MDM also allows admins to control the applications installed on devices, enhancing security and productivity.

  • Blacklist approach: Prohibits specific apps; users can install any others.
  • Whitelist approach: Only allows specified apps; all others are blocked.

MDM solutions like Google Mobile Management provide tools to configure network and device settings remotely.

  • Add and configure Wi-Fi networks across multiple devices
  • Push updates without user intervention
  • Control synchronization, passwords, and encryption settings

Content Management​

Content management is a security control that restricts access to inappropriate websites and can block certain content types, such as images in emails.

  • Enforces corporate content policies on mobile devices
  • Helps prevent data leaks and policy violations off-campus

Device Tracking​

  • Impact of Lost or Stolen Devices

    • When devices are lost or stolen, organizations face two types of losses:
      • Loss of the physical device (financial cost).
      • Potential loss of data if encryption isn’t enabled.

  • Device Costs

    • High-end devices can cost over $1,000, making their loss significant.
    • Over 3.1 million mobile devices are stolen annually in the U.S.

  • Asset Tracking Software

    • Helps organizations manage the lifecycle of computing assets.
    • Covers smartphones, laptops, desktops, servers, and printers.
    • Often integrated with device management or IT service management solutions.

  • Lifecycle Management

    • Asset tracking software covers the entire lifecycle of a device:
      • Includes initial request, ordering, receiving, and configuration.
      • Applies security policies and labels devices as organizational property.
      • Assigns devices to users and reassigns as needed.
      • Ensures secure decommissioning by removing data and discarding devices.

  • Real-Time Tracking for Certain Industries

    • Some industries, like delivery services, use GPS tracking to:
      • Manage driver performance.
      • Optimize routes.

  • Privacy Concerns with GPS Tracking

    • Organizations must disclose GPS tracking to employees.
    • Implement access restrictions to GPS data.
    • Provide the ability to disable tracking outside of working hours.
    • Establish clear policies on the use of location data.

Hardening Mobile Devices​

  • Mobile Device Management

  • Sideloading

    • Instead of installing app from the app store, use the actual packages.
    • Security risk, attacker can install app which allow them full access to the phone.

  • SE Android

    • Mobile functions are limited.
    • Security clearance is needed to use the device.
    • Used in stringent, high-security environments.

  • Unified Endpoint Management

    • Can be used to deploy FW settings on smartphones
    • Centrally deploy virus updates, install apps, etc.

  • Others

    • Reduce the attack surface
    • Disabling bluetooth, WIFI, or NFC
    • Use strong authentication
    • Enable full device encryption