Skip to content

Latest commit

 

History

History
92 lines (71 loc) · 9.29 KB

threat-modeling.md

File metadata and controls

92 lines (71 loc) · 9.29 KB

Threat Model Analysis for standardnotes/app

Threat: Weak Client-Side Key Generation

  • Description: An attacker might attempt to predict or brute-force private keys if the client-side key generation process uses weak random number generation or flawed algorithms. This could be done through statistical analysis or known weaknesses in the key generation process.
    • Impact: Critical. Complete compromise of user's private key, allowing decryption of all notes by the attacker.
    • Affected Component: Key Generation Module (within client applications - web, desktop, mobile)
    • Risk Severity: Critical
    • Mitigation Strategies:
      • Developer: Utilize cryptographically secure random number generators (CSPRNGs) provided by the operating system or well-vetted libraries. Implement established key derivation functions (KDFs) and ensure proper seeding of RNGs. Conduct security audits of key generation code.

Threat: Insecure Client-Side Key Storage

  • Description: An attacker gaining local access to a user's device could attempt to extract private keys if they are stored insecurely. This could involve accessing files in predictable locations, exploiting insufficient file permissions, or bypassing weak encryption of the key storage.
    • Impact: Critical. Compromise of user's private key, allowing decryption of all notes by the attacker if they gain local device access.
    • Affected Component: Local Key Storage Module (within client applications - web, desktop, mobile)
    • Risk Severity: Critical
    • Mitigation Strategies:
      • Developer: Employ platform-specific secure storage mechanisms like Keychain (macOS/iOS), Credential Manager (Windows), Keystore (Android). Encrypt keys before storing them locally. Implement proper file permissions to restrict access to key storage.

Threat: Weak Key Derivation Function (KDF)

  • Description: An attacker obtaining a user's password hash (e.g., from a server breach or phishing) could attempt offline brute-force or dictionary attacks to recover the password and subsequently derive the encryption keys if a weak KDF is used.
    • Impact: High. Offline password cracking could lead to the derivation of encryption keys, allowing decryption of notes.
    • Affected Component: Password Handling and Key Derivation Function (within client applications and potentially server-side for password storage if applicable)
    • Risk Severity: High
    • Mitigation Strategies:
      • Developer: Use strong and well-vetted KDFs like Argon2id or PBKDF2-HMAC-SHA256 with high iteration counts and unique salts per user. Regularly review and update KDF parameters based on security best practices.

Threat: Implementation Flaws in Encryption/Decryption Logic

  • Description: Developers might introduce bugs or errors in the code implementing encryption and decryption. An attacker could exploit these flaws to bypass encryption, cause data leakage, or perform side-channel attacks.
    • Impact: High. Data breaches, potential for partial or full decryption of notes due to implementation errors.
    • Affected Component: Encryption/Decryption Logic (specific code implementing cryptographic operations within the application)
    • Risk Severity: High
    • Mitigation Strategies:
      • Developer: Conduct thorough code reviews, security audits, and penetration testing specifically focusing on encryption and decryption logic. Utilize well-tested and audited cryptographic libraries instead of implementing custom cryptography where possible. Employ static and dynamic analysis tools to detect potential vulnerabilities.

Threat: Sync Service Compromise (Server-Side)

  • Description: Although server-side, a compromise of Standard Notes' server infrastructure could allow an attacker to access user metadata or manipulate sync data. While note content is encrypted, server compromise can have significant impact.
    • Impact: High. Data breaches (metadata), potential for data manipulation, service disruption, loss of user trust.
    • Affected Component: Server Infrastructure, Sync Service (Standard Notes backend servers)
    • Risk Severity: High (for the overall ecosystem, though less directly "app-introduced")
    • Mitigation Strategies:
      • Developer (Server-Side): Implement robust security measures for server infrastructure: strong access controls, intrusion detection, regular security audits, incident response plans, secure server configuration, and patching.

Threat: Unencrypted Local Storage

  • Description: Developers might accidentally or intentionally store notes or encryption keys in unencrypted form in local storage (e.g., browser local storage, application files). An attacker with local device access could easily read this data.
    • Impact: Critical. Complete compromise of note confidentiality if local storage is accessed by an attacker or malware.
    • Affected Component: Local Storage Module (within client applications)
    • Risk Severity: Critical
    • Mitigation Strategies:
      • Developer: Enforce encryption for all locally stored data, including notes and encryption keys. Regularly audit local storage mechanisms to ensure no unencrypted data is present. Use secure coding practices to prevent accidental unencrypted storage.

Threat: Insufficient Local Storage Protection

  • Description: Even if encrypted, local storage might have insufficient platform-level protection (e.g., weak file permissions). An attacker or malicious application on the same device could potentially access the encrypted data.
    • Impact: High. Unauthorized access to encrypted notes if local storage protection is insufficient, potentially leading to decryption.
    • Affected Component: Local Storage Module, File System Permissions (within client applications)
    • Risk Severity: High
    • Mitigation Strategies:
      • Developer: Utilize platform-specific secure storage mechanisms that provide access control. Ensure proper file permissions are set to restrict access to local storage to only the Standard Notes application and the user.

Threat: Malicious Extensions

  • Description: Users might install malicious extensions designed to steal decrypted notes, inject malicious code, or compromise application security. Extensions could be distributed through unofficial channels or compromised official channels.
    • Impact: Critical to High. Data breaches (note theft), malware infection, compromise of application functionality, depending on extension capabilities.
    • Affected Component: Extensions System, Extensions API (within client applications)
    • Risk Severity: High
    • Mitigation Strategies:
      • Developer: Implement a robust extension vetting and review process. Provide clear warnings to users about extension risks. Consider sandboxing extensions to limit their access to application resources and data. Implement a permission system for extensions.

Threat: Vulnerable Extensions

  • Description: Even legitimate extensions might contain security vulnerabilities (XSS, code injection). An attacker could exploit these vulnerabilities to compromise the application or user data through a seemingly trusted extension.
    • Impact: High. Data breaches, application compromise, potential for cross-site scripting attacks within the application context.
    • Affected Component: Extensions System, Extensions API, Individual Extensions (within client applications)
    • Risk Severity: High
    • Mitigation Strategies:
      • Developer: Encourage extension developers to follow secure coding practices. Provide security guidelines and tools for extension development. Implement automated security scanning for extensions. Offer bug bounty programs for extension vulnerabilities.

Threat: Supply Chain Attacks on Extensions

  • Description: Extension repositories or distribution channels could be compromised, leading to the distribution of malicious or backdoored extensions. This could affect a large number of users who trust the official channels.
    • Impact: Critical. Widespread distribution of malicious extensions, potentially affecting a large number of users, leading to data breaches and widespread compromise.
    • Affected Component: Extension Distribution System, Extension Repositories (infrastructure related to extension distribution)
    • Risk Severity: Critical
    • Mitigation Strategies:
      • Developer: Implement secure extension distribution mechanisms. Verify the integrity of extensions using checksums or digital signatures. Use code signing to ensure extension authenticity. Regularly audit extension distribution infrastructure.