Mobile Security Hardening: Complete Protection Guide

Android & iOS security settings, apps, and commands

ESSENTIAL SECURITY

Android: Core Settings

Enable Google Play Protect

Settings → Security → Google Play Protect → Scan apps with Play Protect: ON
→ Improve harmful app detection: ON

Find My Device

Settings → Security → Find My Device: ON

Track/erase remotely at android.com/find

Screen Lock (Strongest First)

Settings → Security → Screen lock:
1. Fingerprint + PIN/Password (Recommended)
2. Strong PIN (6+ digits, not birthday)
3. Password (12+ characters)
AVOID: Pattern (smudge attacks), 4-digit PIN

Lockdown Mode (Android 9+)

Settings → Security → Show lockdown option: ON

Power button → Lockdown: Disables biometrics, requires PIN

iOS: Core Settings

Find My iPhone

Settings → [Your Name] → Find My → Find My iPhone: ON
→ Send Last Location: ON

Stolen Device Protection (iOS 17.3+)

Settings → Face ID & Passcode → Stolen Device Protection: ON

Requires Face ID for password changes, Apple ID modifications

Screen Lock

Settings → Face ID & Passcode → Require Passcode: Immediately
→ Erase Data: ON (10 failed attempts)

ADVANCED HARDENING

Android: Developer Options

Enable Developer Options

Settings → About phone → Build number → Tap 7 times

Security-Focused Settings

Settings → System → Developer options:
→ USB debugging: OFF (keep off unless needed)
→ Verify apps over USB: ON
→ Demo mode: OFF
→ Memory: Check usage

Disable ADB When Not Needed

# If you enabled USB debugging, disable via ADB:
adb shell settings put global adb_enabled 0

iOS: Lockdown Mode (High-Risk Users)

Settings → Privacy & Security → Lockdown Mode: ON

What it blocks:

Most message attachments (images load after click)
Link previews in Messages
Just-in-time (JIT) JavaScript compilation
Incoming FaceTime calls from unknown contacts
Shared albums in Photos
*For journalists, activists, executives *

APP SECURITY

Permission Audit

Android:

Settings → Privacy → Permission manager → Review each permission:
→ Camera: Only messaging/camera apps
→ Microphone: Only calls/recording apps  
→ Location: Only maps/ride apps (set to "Ask every time")
→ Contacts: Only email/messaging apps
→ SMS: ONLY default SMS app

iOS:

Settings → Privacy & Security → [Each permission]
→ Location Services: Set most to "Never" or "Ask Next Time"
→ Photos: "Selected Photos" instead of "All Photos"
→ Local Network: Deny for most apps
→ Bluetooth: Deny unless needed

Remove Unused Apps

Android:

Settings → Apps → [App] → Uninstall
OR
adb shell pm uninstall --user 0 com.package.name

iOS:

Long press app → Remove App → Delete App

NETWORK SECURITY

Private DNS (Android)

Settings → Network & Internet → Private DNS → Private DNS provider hostname:

Enter one:

dns.google                    (Google DNS)
1dot1dot1dot1.cloudflare-dns.com    (Cloudflare)
dns.quad9.net                 (Quad9 - blocks malware)
family.cloudflare-dns.com     (Cloudflare Family - blocks adult content)

DNS Settings (iOS)

Settings → Wi-Fi → [i] next to network → Configure DNS → Manual

Add servers:

1.1.1.1
1.0.0.1
8.8.8.8

Disable Wi-Fi Auto-Join

iOS:

Settings → Wi-Fi → Auto-Join Hotspots: Never
Settings → Wi-Fi → Ask to Join Networks: ON

Android:

Settings → Network & Internet → Wi-Fi → Wi-Fi preferences
→ Turn off Wi-Fi automatically: OFF
→ Open network notifications: OFF

ENCRYPTION & BACKUP

Android Encryption

Settings → Security → Encryption & credentials
→ Require PIN to start device: ON

Modern Android: Encryption is automatic

iOS Backup Encryption

Finder/iTunes → [Device] → Backups → Encrypt local backup: ON
OR
Settings → [Your Name] → iCloud → iCloud Backup: ON
→ Advanced Data Protection: ON (end-to-end encryption)

MESSAGING SECURITY

Switch to Secure Messengers

App	Features	Best For
Signal	Open-source, disappearing messages, sealed sender	Daily communication
WhatsApp	End-to-end encryption, 2 billion users	International calls
Telegram	Secret chats, self-destruct	Large groups (avoid regular chats)
iMessage	E2E Apple-to-Apple, no phone number needed	iOS users

Signal Security Settings:

Signal → Settings → Privacy:
→ Screen Lock: ON
→ Screen Lock inactivity timeout: 1 minute
→ Disappearing messages: Default 1 week
→ Read receipts: OFF (optional)
→ Typing indicators: OFF (optional)
→ Sealed sender: ON

AUTHENTICATION

Password Manager Setup

Bitwarden (Recommended – Free)

1. Install from Play Store/App Store
2. Create account with STRONG master password (12+ chars)
3. Enable biometric unlock
4. Import passwords from Chrome/Safari
5. Enable Auto-fill: Settings → Auto-fill Services → Bitwarden

Enable 2FA on Password Manager

Bitwarden → Settings → Security → Two-step login → Authenticator app

App-Based 2FA (Never SMS)

Aegis Authenticator (Android – Open Source)

F-Droid/Play Store → Aegis
→ Add accounts via QR code
→ Enable biometric unlock
→ Export encrypted backup to cloud

Raivo OTP (iOS – Open Source)

App Store → Raivo OTP
→ Same setup as above

BLUETOOTH & NFC SECURITY

Disable When Not Needed

Android:

Settings → Connected devices → Connection preferences
→ Bluetooth: OFF (unless using)
→ NFC: OFF (unless using Google Pay)
→ Nearby Share: OFF

iOS:

Settings → Bluetooth: OFF (Control Center doesn't fully disable)
Settings → NFC: OFF (iOS 17+)
Settings → General → AirDrop → Receiving Off

Forget Old Devices

Settings → Bluetooth → [Device] → Forget/Remove

Prevents spoofing attacks

ANTI-THEFT & MONITORING

Android: Find My Device Commands

Website: android.com/find
Actions:
→ Play sound (even if silent)
→ Secure device (lock + display message)
→ Erase device (factory reset)

iOS: Find My Commands

Website: icloud.com/find
OR
Find My app on another Apple device
Actions:
→ Play Sound
→ Lost Mode (lock + track)
→ Erase iPhone

Check for Stolen Status

Android:

Before buying used: Check IMEI at imei.info
Settings → About phone → Status → IMEI information

iOS:

Settings → General → About → IMEI
Check: apple.com/activationlock

PRIVACY CHECKUP

Android Privacy Dashboard

Settings → Privacy → Privacy dashboard
→ See which apps used permissions when
→ Revoke suspicious access

iOS App Privacy Report

Settings → Privacy & Security → App Privacy Report
→ Review network activity and sensor access

Disable Ad Tracking

Android:

Settings → Privacy → Ads → Delete advertising ID
→ Opt out of Ads Personalization: ON

iOS:

Settings → Privacy & Security → Tracking → Allow Apps to Request to Track: OFF
Settings → Privacy & Security → Apple Advertising → Personalized Ads: OFF

ADVANCED: ADB COMMANDS

Audit App Permissions (Android)

# List all packages
adb shell pm list packages

# Check specific app permissions
adb shell dumpsys package com.facebook.katana | grep permission

# Revoke specific permission
adb shell pm revoke com.app.name android.permission.CAMERA

# Disable bloatware (keep package, prevent running)
adb shell pm disable-user --user 0 com.carrier.bloatware

Check for Root/Security Issues

# Verify bootloader status (should be locked)
adb shell getprop ro.boot.verifiedbootstate

# Check for root
adb shell which su
# (Should return nothing if not rooted)

SECURITY CHECKLIST

Task	Android	iOS	Frequency
Update OS	Settings → System → Update	Settings → General → Software Update	Weekly
Update apps	Play Store → Manage apps	App Store → Profile	Weekly
Review permissions	Privacy → Permission manager	Privacy & Security	Monthly
Check Find My	android.com/find	icloud.com/find	Monthly
Backup data	Google One or local	iCloud or Finder	Weekly
Audit apps	Uninstall unused	Remove unused	Monthly
Change passwords	Password manager	Password manager	Quarterly

⚠️ WHAT TO AVOID

❌ Never jailbreak/root (breaks security model)
❌ Don’t sideload apps (outside Play Store/App Store)
❌ Don’t use public USB charging (juice jacking)
❌ Don’t save passwords in browser (use password manager)
❌ Don’t click SMS links (smishing attacks)
❌ Don’t use free VPNs (often malware/data theft)

BONUS: BATTERY & PERFORMANCE

Android Battery Optimization

Settings → Battery → Battery usage → Restrict background for unused apps
Settings → Apps → [App] → Battery → Restricted

iOS Low Power Mode

Settings → Battery → Low Power Mode: ON (or Control Center toggle)

Reduces background activity, mail fetch, visual effects

ESSENTIAL SECURITY

Android: Core Settings

iOS: Core Settings

ADVANCED HARDENING

Android: Developer Options

iOS: Lockdown Mode (High-Risk Users)

APP SECURITY

Permission Audit

Remove Unused Apps

NETWORK SECURITY

Private DNS (Android)

DNS Settings (iOS)

Disable Wi-Fi Auto-Join

ENCRYPTION & BACKUP

Android Encryption

iOS Backup Encryption

MESSAGING SECURITY

Switch to Secure Messengers

AUTHENTICATION

Password Manager Setup

App-Based 2FA (Never SMS)

BLUETOOTH & NFC SECURITY

Disable When Not Needed

Forget Old Devices

ANTI-THEFT & MONITORING

Android: Find My Device Commands

iOS: Find My Commands

Check for Stolen Status

PRIVACY CHECKUP

Android Privacy Dashboard

iOS App Privacy Report

Disable Ad Tracking

ADVANCED: ADB COMMANDS

Audit App Permissions (Android)

Check for Root/Security Issues

SECURITY CHECKLIST

⚠️ WHAT TO AVOID

BONUS: BATTERY & PERFORMANCE

Android Battery Optimization

iOS Low Power Mode

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