Skip to content

Latest commit

 

History

History
224 lines (175 loc) · 18.1 KB

mitigations.md

File metadata and controls

224 lines (175 loc) · 18.1 KB

Mitigation Strategies Analysis for nextcloud/android

Mitigation Strategy: Secure Local Data Storage with Android Keystore Encryption

  • Description:

    1. Identify Sensitive Data: Developers must identify all sensitive data stored locally on the Android device (user credentials, cached files, settings).
    2. Implement Android Keystore: Utilize Android Keystore to generate and securely store encryption keys with strong parameters.
    3. Encrypt Data at Rest: Encrypt sensitive data using keys from Keystore before writing to local storage, using Android's EncryptedFile API or similar. Encrypt Shared Preferences values if needed.
    4. Secure Key Management: Implement secure key lifecycle management, avoiding hardcoding or insecure storage.
    5. Regular Security Audits: Periodically audit encryption implementation and key management.

    • Threats Mitigated:

      • Data Theft from Device (High Severity): Unencrypted data accessible if device is lost/stolen/compromised.
      • Malware Access to Local Data (High Severity): Malware can access unencrypted local data.
      • Physical Access Attacks (Medium Severity): Attackers with physical access can extract unencrypted data.

    • Impact:

      • Data Theft from Device (High Risk Reduction): Encryption makes data unreadable without Keystore key.
      • Malware Access to Local Data (High Risk Reduction): Encryption hinders malware access to sensitive data.
      • Physical Access Attacks (Medium Risk Reduction): Encryption adds protection against physical attacks.

    • Currently Implemented:

      • Likely partially implemented, especially for credentials using Android Keystore. Extent for cached files and settings needs verification.

    • Missing Implementation:

      • Potentially incomplete encryption: Verify encryption of all sensitive cached files, temporary files, and settings.
      • Robustness of key management: Review key rotation and secure handling.
      • Regular audits: Implement scheduled security audits for encryption effectiveness.

Mitigation Strategy: Enforce Runtime Permissions and Principle of Least Privilege

  • Description:

    1. Permission Audit: Audit all Android permissions requested by the application.
    2. Minimize Permissions: Reduce permissions to the minimum necessary. Explore alternatives requiring fewer permissions.
    3. Runtime Permission Requests: Implement runtime requests for all dangerous permissions, just before feature usage.
    4. Clear User Explanations: Explain why each permission is needed when requesting at runtime.
    5. Handle Permission Denials Gracefully: Ensure application functions (partially) even if permissions are denied. Guide users on granting permissions later.
    6. Regular Permission Review: Periodically review permissions as features change.

    • Threats Mitigated:

      • Privacy Violations (Medium to High Severity): Excessive permissions allow unnecessary access to user data.
      • Malicious Permission Abuse (Medium Severity): Compromised app with excessive permissions can be abused by attackers.
      • User Distrust (Low to Medium Severity): Unnecessary permissions can cause user distrust.

    • Impact:

      • Privacy Violations (High Risk Reduction): Minimized permissions limit access to sensitive data.
      • Malicious Permission Abuse (Medium Risk Reduction): Reduced permissions limit potential damage from compromised app.
      • User Distrust (High Risk Reduction): Transparent permission requests enhance user trust.

    • Currently Implemented:

      • Likely partially implemented for sensitive permissions like camera. Full audit needed for all permissions.

    • Missing Implementation:

      • Comprehensive Permission Audit: Audit all permissions in AndroidManifest.xml and code.
      • Runtime Permission for all Dangerous Permissions: Ensure runtime requests for all dangerous permissions.
      • User Explanations for all Permissions: Verify clear explanations for each runtime permission request.
      • Graceful Handling of Denials: Improve app behavior when permissions are denied.

Mitigation Strategy: Secure Intent, Broadcast Receiver, Content Provider, and Service Handling (Android Components)

  • Description:

    1. Intent Security: Use explicit intents primarily. Validate data from implicit intents.
    2. Broadcast Receiver Security: Export receivers only if needed for trusted apps. Implement permission checks and validate broadcast data. Use LocalBroadcastManager for internal broadcasts.
    3. Content Provider Security: Implement strict permission checks and URI permissions. Sanitize inputs to prevent injection/traversal. Re-evaluate necessity of Content Providers.
    4. Service Security: Export services only if needed. Implement permission checks and validate service inputs. Ensure internal services are not exported.

    • Threats Mitigated:

      • Intent Spoofing/Interception (Medium to High Severity): Malicious apps intercepting intents.
      • Broadcast Injection/Spoofing (Medium Severity): Malicious apps sending crafted broadcasts.
      • Content Provider Data Breaches (High Severity): Unauthorized access to content provider data.
      • Service Exploitation (Medium Severity): Exploitable exported services.

    • Impact:

      • Intent Spoofing/Interception (High Risk Reduction): Explicit intents and validation reduce intent-based attacks.
      • Broadcast Injection/Spoofing (High Risk Reduction): Restricted export and validation mitigate broadcast vulnerabilities.
      • Content Provider Data Breaches (High Risk Reduction): Permission checks and input validation prevent data breaches.
      • Service Exploitation (High Risk Reduction): Controlled export and input validation reduce service-based attacks.

    • Currently Implemented:

      • Implementation needs verification. Security posture of intents, receivers, services, and content providers needs review.

    • Missing Implementation:

      • Security Audit of Components: Audit all intents, receivers, content providers, and services.
      • Intent Type Review: Convert implicit to explicit intents where possible. Validate intent data.
      • Receiver Export Review: Review exported receivers, implement permission checks and validation.
      • Content Provider Security Hardening: Implement permission checks, URI permissions, input validation. Re-evaluate necessity.
      • Service Export Review: Review exported services, implement permission checks and input validation.

Mitigation Strategy: Secure WebView Configuration and Usage (Android Component)

  • Description:

    1. Minimize WebView Usage: Avoid WebView if native components suffice.
    2. Disable Unnecessary Features: Disable JavaScript, file access in WebView if not needed.
    3. Input Validation and Output Encoding: Validate input and encode output to prevent XSS in WebView.
    4. URL Whitelisting: Restrict WebView URLs to trusted domains.
    5. Secure Communication within WebView: Use secure channels like postMessage and validate messages.
    6. Regular WebView Updates: Use latest WebView version for security patches.

    • Threats Mitigated:

      • Cross-Site Scripting (XSS) in WebView (High Severity): XSS vulnerabilities due to insecure WebView and unsanitized input.
      • Local File Access Vulnerabilities (Medium Severity): Unauthorized file access if enabled in WebView.
      • URL Redirection Attacks (Medium Severity): Unvalidated URLs redirecting to malicious sites.
      • JavaScript Injection (Medium to High Severity): Exploiting web content to inject malicious JavaScript.

    • Impact:

      • Cross-Site Scripting (XSS) in WebView (High Risk Reduction): Secure config, validation, encoding reduce XSS risk.
      • Local File Access Vulnerabilities (High Risk Reduction): Disabling file access eliminates this risk.
      • URL Redirection Attacks (Medium Risk Reduction): URL whitelisting prevents redirection attacks.
      • JavaScript Injection (Medium to High Risk Reduction): Disabling/managing JavaScript reduces injection risk.

    • Currently Implemented:

      • Implementation needs verification. Check WebView usage and configuration in Nextcloud Android.

    • Missing Implementation:

      • WebView Usage Audit: Identify all WebView usages in code.
      • Secure WebView Configuration: Harden WebView settings by disabling unnecessary features.
      • Input Validation and Output Encoding for WebView: Implement validation and encoding for WebView content.
      • URL Whitelisting for WebView: Implement URL whitelisting.
      • Secure WebView Communication Review: Review and secure WebView communication channels.

Mitigation Strategy: Device Security Posture Considerations and User Guidance (Android Specific)

  • Description:

    1. In-App User Guidance: Educate users within the app about Android device security best practices.
    2. Strong Screen Lock Promotion: Encourage users to set strong screen locks (PIN, password, biometric) on their Android devices.
    3. OS Update Reminders: Remind users to keep their Android OS updated for security patches.
    4. Untrusted Source Warning: Warn users against installing apps from untrusted sources (sideloading).
    5. Optional Security Checks (with caution): Consider optional checks for device security settings (screen lock enabled) to provide warnings, but avoid blocking core functionality.

    • Threats Mitigated:

      • Device Compromise due to weak device security (Medium Severity): Weak screen locks or outdated OS increase risk of device compromise.
      • Malware Installation from Untrusted Sources (Medium to High Severity): Sideloading apps increases risk of malware infection.
      • Physical Access Attacks (Low to Medium Severity): Strong screen locks deter casual physical access attacks.

    • Impact:

      • Device Compromise due to weak device security (Medium Risk Reduction): User education and reminders improve device security posture.
      • Malware Installation from Untrusted Sources (Medium Risk Reduction): Warnings reduce risk of installing malicious apps.
      • Physical Access Attacks (Low to Medium Risk Reduction): Strong screen locks provide basic physical security.

    • Currently Implemented:

      • Likely partially implemented through general help documentation. In-app, proactive guidance might be missing.

    • Missing Implementation:

      • In-App Security Tips and Guidance: Integrate security tips directly within the app.
      • Proactive Reminders: Implement proactive reminders for strong screen locks and OS updates.
      • Sideloading Warnings: Display clear warnings about risks of sideloading apps.

Mitigation Strategy: Code Security Practices (Android Specific)

  • Description:

    1. Android-Specific Secure Coding Guidelines: Establish and enforce Android-specific secure coding guidelines for developers.
    2. Android Lint and Static Analysis: Utilize Android Lint and other static analysis tools to detect Android-specific vulnerabilities in code.
    3. Dynamic Code Analysis: Integrate dynamic analysis tools to detect runtime Android vulnerabilities.
    4. Regular Security Code Reviews (Android Focused): Conduct security code reviews specifically looking for Android-related vulnerabilities and guideline adherence.

    • Threats Mitigated:

      • Android-Specific Vulnerabilities (Medium to High Severity): Exploitable vulnerabilities specific to the Android platform (e.g., insecure intent handling, permission bypasses).
      • Common Android Coding Errors (Low to Medium Severity): Common coding mistakes that can lead to security weaknesses in Android apps.

    • Impact:

      • Android-Specific Vulnerabilities (High Risk Reduction): Secure coding practices, static/dynamic analysis, and reviews significantly reduce Android-specific vulnerabilities.
      • Common Android Coding Errors (Medium Risk Reduction): Guidelines and analysis tools help prevent common coding errors.

    • Currently Implemented:

      • Likely partially implemented through general code review processes. Android-specific focus and tooling might be missing.

    • Missing Implementation:

      • Formal Android Secure Coding Guidelines: Document and enforce Android-specific secure coding guidelines.
      • Integration of Android Lint and Static Analysis: Integrate and regularly use Android Lint and other static analysis tools.
      • Dynamic Analysis Integration: Explore and integrate dynamic analysis tools for Android.
      • Android-Focused Security Code Reviews: Implement regular code reviews with a specific focus on Android security.

Mitigation Strategy: Rooted/Compromised Device Handling (Android Specific)

  • Description:

    1. Root Detection Implementation (with caution): Consider implementing root detection mechanisms.
    2. Graceful Handling of Rooted Devices: Decide on a strategy for rooted devices: warnings, limited functionality, or blocking (weigh usability).
    3. Hostile Environment Assumption: Develop with the assumption that the app might run on a compromised device, especially for sensitive data handling.

    • Threats Mitigated:

      • Compromised Device Exploitation (High Severity): Rooted/compromised devices are more vulnerable to malware and attacks.
      • Data Leakage on Rooted Devices (High Severity): Root access can bypass application security measures and access data.
      • Bypassing Security Controls (Medium to High Severity): Root access can be used to bypass security controls implemented by the application.

    • Impact:

      • Compromised Device Exploitation (Medium Risk Reduction): Root detection and handling can mitigate risks on compromised devices.
      • Data Leakage on Rooted Devices (Medium Risk Reduction): Handling rooted devices can limit data leakage, but root access is powerful.
      • Bypassing Security Controls (Medium Risk Reduction): Mitigation strategies can make it harder to bypass controls, but root access is a significant challenge.

    • Currently Implemented:

      • Implementation status needs verification. Root detection and handling might not be implemented or might be basic.

    • Missing Implementation:

      • Root Detection Implementation (if not present): Implement root detection if deemed necessary and beneficial.
      • Defined Rooted Device Handling Strategy: Define a clear strategy for handling rooted devices.
      • Security Hardening with Hostile Environment in Mind: Enhance security measures assuming a potentially compromised environment.

Mitigation Strategy: User Education and Awareness (Android Security Focus)

  • Description:

    1. In-App Android Security Education: Integrate educational content within the app specifically about Android security.
    2. Android Permission Education: Explain Android permissions within the app and why the app requests specific permissions.
    3. Device Lock Guidance (Android): Guide users on setting up strong Android device locks (PIN, password, biometric).
    4. Android OS Update Importance: Educate users about the importance of keeping their Android OS updated for security.
    5. Risks of Sideloading (Android): Inform users about the security risks of installing apps from outside official Android app stores.

    • Threats Mitigated:

      • User-Driven Security Lapses (Low to Medium Severity): Users making insecure choices due to lack of awareness.
      • Social Engineering Attacks (Low to Medium Severity): Educated users are less susceptible to social engineering related to Android security.
      • Unintentional Permission Granting (Low Severity): Users understanding permissions are less likely to grant unnecessary permissions unknowingly.

    • Impact:

      • User-Driven Security Lapses (Medium Risk Reduction): Education reduces user-driven security mistakes.
      • Social Engineering Attacks (Low Risk Reduction): Increased awareness makes users slightly less vulnerable to Android-related social engineering.
      • Unintentional Permission Granting (Medium Risk Reduction): Education helps users make informed permission decisions.

    • Currently Implemented:

      • Likely minimal. General help documentation might exist, but targeted in-app Android security education is probably missing.

    • Missing Implementation:

      • In-App Android Security Education Modules: Create dedicated in-app modules or sections for Android security education.
      • Permission Explanation Integration: Integrate permission explanations directly into the permission request flow.
      • Proactive Security Tips: Display proactive security tips related to Android device security within the app.