CWE-325 Base Brouillon

Missing Cryptographic Step

This vulnerability occurs when a software implementation skips a critical step in a cryptographic process, resulting in security that is significantly weaker than the intended algorithm provides.

Définition

What is CWE-325?

This vulnerability occurs when a software implementation skips a critical step in a cryptographic process, resulting in security that is significantly weaker than the intended algorithm provides.
Cryptographic algorithms are designed as a sequence of specific, interdependent steps. Each step serves a purpose, such as ensuring randomness, preventing pattern analysis, or binding data together securely. When a developer omits one of these steps—whether during key generation, encryption, decryption, or integrity verification—the entire cryptographic operation becomes fragile. The resulting system may appear to function normally but can be easily broken by attackers using well-known techniques, completely undermining the promised security. This flaw often stems from using incomplete code samples, misunderstanding algorithm specifications, or attempting to 'optimize' performance by removing so-called 'unnecessary' operations. To prevent it, developers should rely on reputable, high-level cryptographic libraries rather than implementing algorithms from scratch. Always follow the official algorithm specification or RFC meticulously, and use established test vectors to verify that every required step is correctly executed in the proper order.
Impact réel

Real-world CVEs caused by CWE-325

  • CVE-2001-1585

    Missing challenge-response step allows authentication bypass using public key.

Comment les attaquants l'exploitent

Parcours de l'attaquant étape par étape

  1. 1

    The example code is taken from the HMAC engine inside the buggy OpenPiton SoC of HACK@DAC'21 [REF-1358]. HAMC is a message authentication code (MAC) that uses both a hash and a secret crypto key. The HMAC engine in HACK@DAC SoC uses the SHA-256 module for the calculation of the HMAC for 512 bits messages.

  2. 2

    However, this HMAC engine cannot handle messages that are longer than 512 bits. Moreover, a complete HMAC will contain an iterate hash function that breaks up a message into blocks of a fixed size and iterates over them with a compression function (e.g., SHA-256). Therefore, the implementation of the HMAC in OpenPiton SoC is incomplete. Such HMAC engines will not be used in real-world applications as the messages will usually be longer than 512 bits. For instance, OpenTitan offers a comprehensive HMAC implementation that utilizes a FIFO for temporarily storing the truncated message, as detailed in [REF-1359].

  3. 3

    To mitigate this, implement the iterative function to break up a message into blocks of a fixed size.

Exemple de code vulnérable

Vulnerable Verilog

The example code is taken from the HMAC engine inside the buggy OpenPiton SoC of HACK@DAC'21 [REF-1358]. HAMC is a message authentication code (MAC) that uses both a hash and a secret crypto key. The HMAC engine in HACK@DAC SoC uses the SHA-256 module for the calculation of the HMAC for 512 bits messages.

Vulnérable Verilog 
**logic [511:0] bigData;** 
 ...

 hmac hmac(

```
   .clk_i(clk_i),
   .rst_ni(rst_ni && ~rst_4),
   .init_i(startHash && ~startHash_r),
   .key_i(key),
   .ikey_hash_i(ikey_hash), 
   .okey_hash_i(okey_hash), 
   .key_hash_bypass_i(key_hash_bypass),
```
.message_i(bigData),** 
   .hash_o(hash),
   .ready_o(ready),
   .hash_valid_o(hashValid)
Exemple de code sécurisé

Secure pseudo

Sécurisé pseudo 
// Validate, sanitize, or use a safe API before reaching the sink.
function handleRequest(input) {
  const safe = validateAndEscape(input);
  return executeWithGuards(safe);
}
What changed: the unsafe sink is replaced (or the input is validated/escaped) so the same payload no longer triggers the weakness.
Liste de contrôle de prévention

How to prevent CWE-325

  • Architecture Use safe-by-default frameworks and APIs that prevent the unsafe pattern from being expressible.
  • Implementation Validate input at trust boundaries; use allowlists, not denylists.
  • Implementation Apply the principle of least privilege to credentials, file paths, and runtime permissions.
  • Testing Cover this weakness in CI: SAST rules + targeted unit tests for the data flow.
  • Operation Monitor logs for the runtime signals listed in the next section.
Signaux de détection

How to detect CWE-325

SAST High

Exécuter une analyse statique (SAST) sur le code source à la recherche du motif non sécurisé dans le flux de données.

DAST Moderate

Exécuter des tests de sécurité applicative dynamique (DAST) contre le point de terminaison en ligne.

Runtime Moderate

Surveiller les journaux runtime pour détecter des traces d'exception inhabituelles, des entrées malformées ou des tentatives de contournement d'autorisation.

Code review Moderate

Revue de code : signaler tout nouveau code qui traite les entrées de cette surface sans utiliser les helpers du framework validés.

Correction automatique Plexicus

Plexicus détecte automatiquement CWE-325 et ouvre une PR de correction en moins de 60 secondes.

Codex Remedium analyse chaque commit, identifie cette faiblesse précise et livre une pull request prête à être relue avec le correctif. Pas de tickets. Pas de transferts.

Obtenir une démo Essayer Plexicus gratuitement
Questions fréquentes

Frequently asked questions

Qu'est-ce que CWE-325 ?

This vulnerability occurs when a software implementation skips a critical step in a cryptographic process, resulting in security that is significantly weaker than the intended algorithm provides.

Quelle est la gravité de CWE-325 ?

MITRE n'a pas publié de note de probabilité d'exploitation pour cette faiblesse. Traitez-la comme un impact moyen jusqu'à ce que votre modèle de menace prouve le contraire.

Quels langages ou plateformes sont affectés par CWE-325 ?

MITRE lists the following affected platforms: Not Technology-Specific.

Comment puis-je prévenir CWE-325 ?

Use safe-by-default frameworks, validate untrusted input at trust boundaries, and apply the principle of least privilege. Cover the data-flow signature in CI with SAST.

Comment Plexicus détecte et corrige CWE-325 ?

Le moteur SAST de Plexicus reconnaît la signature de flux de données de CWE-325 à chaque commit. Lorsqu'une correspondance est trouvée, notre agent Codex Remedium ouvre une PR de correction avec le code corrigé, les tests et un résumé d'une ligne pour le relecteur.

Où puis-je en savoir plus sur CWE-325 ?

MITRE publie la définition canonique à https://cwe.mitre.org/data/definitions/325.html. Vous pouvez également consulter la documentation OWASP et NIST pour des conseils adjacents.

Faiblesses associées

Weaknesses related to CWE-325

CWE-573 Parent

Improper Following of Specification by Caller

This weakness occurs when software fails to properly follow the documented rules, protocols, or requirements of an external component it…

CWE-103 Frère

Struts: Incomplete validate() Method Definition

This vulnerability occurs in a Struts application when a validator form either completely omits a validate() method or includes one but…

CWE-104 Frère

Struts: Form Bean Does Not Extend Validation Class

This vulnerability occurs in Apache Struts applications when a form bean class does not properly extend the framework's validation class.…

CWE-243 Frère

Creation of chroot Jail Without Changing Working Directory

This vulnerability occurs when a program creates a chroot jail but fails to change its current working directory afterward. Because the…

CWE-253 Frère

Incorrect Check of Function Return Value

This vulnerability occurs when a program misinterprets or improperly validates the return value from a function, causing it to miss…

CWE-296 Frère

Improper Following of a Certificate's Chain of Trust

This vulnerability occurs when software fails to properly validate the entire certificate chain back to a trusted root authority. This…

CWE-304 Frère

Missing Critical Step in Authentication

This vulnerability occurs when a software authentication process omits a required step, weakening its overall security.

CWE-329 Frère

Generation of Predictable IV with CBC Mode

This vulnerability occurs when software uses a predictable or reused Initialization Vector (IV) with Cipher Block Chaining (CBC) mode…

CWE-358 Frère

Improperly Implemented Security Check for Standard

This vulnerability occurs when software fails to correctly implement one or more critical security checks required by a standard protocol,…

Ressources

Further reading

Prêt quand vous l'êtes

Arrêtez de payer par développeur.
Commencez à fermer la boucle.

Plexicus est l'ASPM natif IA qui scanne, filtre, corrige, penteste et explique — de façon autonome. Développeurs illimités, dépôts illimités, actions IA à usage équitable. Vrai niveau gratuit, €269/mo annuel quand vous êtes prêt.

Commencer gratuitement Réserver une démo