Skip to content

Latest commit

 

History

History
62 lines (49 loc) · 6.63 KB

attack-surface.md

File metadata and controls

62 lines (49 loc) · 6.63 KB

Attack Surface Analysis for krzyzanowskim/cryptoswift

Attack Surface: Weak Cryptographic Algorithm Selection

  • Description: Choosing outdated, weak, or inappropriate cryptographic algorithms for the specific security needs.
  • How CryptoSwift Contributes: CryptoSwift provides a range of algorithms, including some that are considered weak or deprecated for certain use cases (e.g., MD5, SHA1, single DES). The library's API allows their use, making it possible for developers to make insecure choices.
  • Example: Using MD5 for hashing passwords, or using single DES for encrypting sensitive data, because CryptoSwift makes these algorithms available.
  • Impact: Compromised data integrity, confidentiality, or authentication. Attackers could forge messages, decrypt data, or bypass authentication mechanisms.
  • Risk Severity: Critical (if weak algorithms are used for critical functions) or High (if used for less critical functions).
  • Mitigation Strategies:
    • Developer: Enforce a strict policy to use only strong, recommended algorithms (e.g., SHA-256/SHA-3 for hashing, AES-256 with GCM or ChaCha20-Poly1305 for encryption). Document approved algorithms and their appropriate use cases. Use configuration files or environment variables to manage algorithm choices, facilitating updates. Conduct regular code reviews to ensure adherence to the policy.

Attack Surface: Insecure Mode of Operation (Block Ciphers)

  • Description: Using an insecure block cipher mode of operation (e.g., ECB) or misconfiguring a secure mode (e.g., reusing a nonce with CTR or GCM).
  • How CryptoSwift Contributes: CryptoSwift supports various block cipher modes, including both secure and insecure options (like ECB). The library's API allows the developer to select and configure the mode, making insecure choices possible.
  • Example: Using AES in ECB mode, or reusing the same IV/nonce with AES-GCM for multiple encryption operations with the same key, because CryptoSwift provides these modes and doesn't prevent misuse.
  • Impact: Leakage of plaintext information, potential for chosen-ciphertext attacks, loss of authentication (if using an authenticated mode incorrectly).
  • Risk Severity: Critical
  • Mitigation Strategies:
    • Developer: Prioritize authenticated encryption modes (GCM, ChaCha20-Poly1305). If other modes are necessary, strictly follow their security requirements. Never reuse nonces with CTR or GCM. Use a CSPRNG to generate IVs. Provide clear documentation and code examples for developers on correct mode usage. Implement automated checks to prevent nonce reuse.

Attack Surface: Padding Oracle Attacks (CBC Mode)

  • Description: Exploiting vulnerabilities in applications that use CBC mode with PKCS#7 padding and reveal information about padding errors.
  • How CryptoSwift Contributes: CryptoSwift supports CBC mode with PKCS#7 padding. While the vulnerability is primarily in application-level error handling, the availability of this mode in CryptoSwift is a prerequisite for the attack.
  • Example: An application using CryptoSwift's CBC mode implementation returns different error messages or exhibits different response times depending on whether the padding is valid or invalid.
  • Impact: Complete decryption of ciphertext without knowledge of the key.
  • Risk Severity: Critical
  • Mitigation Strategies:
    • Developer: Preferentially use authenticated encryption modes (GCM, ChaCha20-Poly1305) which are inherently resistant. If CBC must be used, ensure constant-time handling of padding errors. Never reveal any information about padding validity to the attacker. Implement a MAC to verify ciphertext integrity before decryption.

Attack Surface: Insecure Random Number Generation (for Keys, IVs, Nonces)

  • Description: Using a weak or predictable random number generator to generate keys/IVs/nonces.
  • How CryptoSwift Contributes: While CryptoSwift provides access to CSPRNGs, it doesn't enforce their use. A developer could choose to use an insecure alternative, or misuse the provided CSPRNG (e.g., incorrect seeding). This is a direct contribution because the library is the intended source of randomness.
  • Example: A developer bypassing CryptoSwift's CSPRNG and using a less secure method to generate an AES key or IV.
  • Impact: Weak keys, predictable IVs/nonces, leading to compromised security.
  • Risk Severity: Critical
  • Mitigation Strategies:
    • Developer: Always use the CSPRNG provided by CryptoSwift (or the underlying operating system, as exposed by CryptoSwift) for generating keys, IVs, and nonces. Ensure the CSPRNG is properly seeded. Avoid any predictable values.

Attack Surface: Insufficient Key Size

  • Description: Using key sizes that are too small for the chosen algorithm.
  • How CryptoSwift Contributes: CryptoSwift allows for various key sizes to be used with different algorithms. The library does not enforce minimum key size requirements, making it possible for developers to choose insecurely small key sizes.
  • Example: Using AES with a 128-bit key when 256-bit is recommended, because CryptoSwift allows the 128-bit option.
  • Impact: Increased susceptibility to brute-force attacks.
  • Risk Severity: High
  • Mitigation Strategies:
    • Developer: Enforce minimum key sizes based on current cryptographic recommendations (e.g., AES-256, RSA-2048 or higher). Validate key sizes during key generation and usage. Document the required key sizes.

Attack Surface: Using Outdated CryptoSwift Version

  • Description: Using an old version of the CryptoSwift library that may contain known security vulnerabilities.
  • How CryptoSwift Contributes: This is directly related to CryptoSwift. Older versions of the library itself may have vulnerabilities.
  • Example: Using a version of CryptoSwift with a known vulnerability in its AES implementation.
  • Impact: Exposure to known exploits.
  • Risk Severity: High (depending on the specific vulnerabilities)
  • Mitigation Strategies:
    • Developer: Regularly update CryptoSwift to the latest stable version. Monitor security advisories. Use dependency management tools.