CWE-1240
Use of a Cryptographic Primitive with a Risky Implementation
To fulfill the need for a cryptographic primitive, the product implements a cryptographic algorithm using a non-standard, unproven, or disallowed/non-compliant cryptographic implementation.
Mitigation ID: MIT-55
Phase: Requirements
Description:
- Require compliance with the strongest-available recommendations from trusted parties, and require that compliance must be kept up-to-date, since recommendations evolve over time. For example, US government systems require FIPS 140-3 certification, which supersedes FIPS 140-2 [REF-1192] [REF-267].
Mitigation
Phase: Architecture and Design
Description:
- Ensure that the architecture/design uses the strongest-available primitives and algorithms from trusted parties. For example, US government systems require FIPS 140-3 certification, which supersedes FIPS 140-2 [REF-1192] [REF-267].
Mitigation ID: MIT-54
Phase: Architecture and Design
Description:
- Do not develop custom or private cryptographic algorithms. They will likely be exposed to attacks that are well-understood by cryptographers. As with all cryptographic mechanisms, the source code should be available for analysis. If the algorithm may be compromised when attackers find out how it works, then it is especially weak.
Mitigation
Phase: Architecture and Design
Description:
- Try not to use cryptographic algorithms in novel ways or with new modes of operation even when you "know" it is secure. For example, using SHA-2 chaining to create a 1-time pad for encryption might sound like a good idea, but one should not do this.
Mitigation ID: MIT-52
Phase: Architecture and Design
Description:
- Ensure that the design can replace one cryptographic primitive or algorithm with another in the next generation ("cryptographic agility"). Where possible, use wrappers to make the interfaces uniform. This will make it easier to upgrade to stronger algorithms. This is especially important for hardware, which can be more difficult to upgrade quickly than software; design the hardware at a replaceable block level.
Mitigation
Phase: Architecture and Design
Description:
- Do not use outdated or non-compliant cryptography algorithms. Some older algorithms, once thought to require a billion years of computing time, can now be broken in days or hours. This includes MD4, MD5, SHA1, DES, and other algorithms that were once regarded as strong [REF-267].
Mitigation
Phases: Architecture and Design, Implementation
Description:
- Do not use a linear-feedback shift register (LFSR) or other legacy methods as a substitute for an accepted and standard Random Number Generator.
Mitigation
Phases: Architecture and Design, Implementation
Description:
- Do not use a checksum as a substitute for a cryptographically generated hash.
Mitigation
Phase: Architecture and Design
Strategy: Libraries or Frameworks
Description:
- Use a vetted cryptographic library or framework. Industry-standard implementations will save development time and are more likely to avoid errors that can occur during implementation of cryptographic algorithms. However, the library/framework could be used incorrectly during implementation.
Mitigation
Phases: Architecture and Design, Implementation
Description:
- When using industry-approved techniques, use them correctly. Don't cut corners by skipping resource-intensive steps (CWE-325). These steps are often essential for the prevention of common attacks.
Mitigation
Phases: Architecture and Design, Implementation
Description:
- Do not store keys in areas accessible to untrusted agents. Carefully manage and protect the cryptographic keys (see CWE-320). If the keys can be guessed or stolen, then the strength of the cryptography algorithm is irrelevant.
CAPEC-97: Cryptanalysis
Cryptanalysis is a process of finding weaknesses in cryptographic algorithms and using these weaknesses to decipher the ciphertext without knowing the secret key (instance deduction). Sometimes the weakness is not in the cryptographic algorithm itself, but rather in how it is applied that makes cryptanalysis successful. An attacker may have other goals as well, such as: Total Break (finding the secret key), Global Deduction (finding a functionally equivalent algorithm for encryption and decryption that does not require knowledge of the secret key), Information Deduction (gaining some information about plaintexts or ciphertexts that was not previously known) and Distinguishing Algorithm (the attacker has the ability to distinguish the output of the encryption (ciphertext) from a random permutation of bits).