CWE-385 Base Incomplet Medium likelihood

Covert Timing Channel

A covert timing channel is a security flaw where an attacker can deduce secret information by observing how long certain operations take to execute. Instead of directly reading data, they analyze…

Définition

What is CWE-385?

A covert timing channel is a security flaw where an attacker can deduce secret information by observing how long certain operations take to execute. Instead of directly reading data, they analyze timing variations in system behavior to infer protected details.
Attackers can exploit timing differences to learn secrets they shouldn't have access to. For instance, if a cryptographic function or a database query takes slightly longer under specific conditions, that delay can leak information about the internal state of the operation or the data being processed. Monitoring these subtle time variations allows an attacker to piece together sensitive information. This type of vulnerability is a classic example of a side-channel attack, specifically a timing channel. Common real-world signals include variations in a system's paging rate, the execution time of a transaction, or the delay in accessing a shared resource. Defending against these attacks requires ensuring that operations complete in constant time, regardless of the input or secret data involved.
Impact réel

Real-world CVEs caused by CWE-385

Aucune référence CVE publique n'est liée à ce CWE dans le catalogue MITRE pour le moment.

Comment les attaquants l'exploitent

Parcours de l'attaquant étape par étape

  1. 1

    In this example, the attacker observes how long an authentication takes when the user types in the correct password.

  2. 2

    When the attacker tries their own values, they can first try strings of various length. When they find a string of the right length, the computation will take a bit longer, because the for loop will run at least once. Additionally, with this code, the attacker can possibly learn one character of the password at a time, because when they guess the first character right, the computation will take longer than a wrong guesses. Such an attack can break even the most sophisticated password with a few hundred guesses.

  3. 3

    Note that in this example, the actual password must be handled in constant time as far as the attacker is concerned, even if the actual password is of an unusual length. This is one reason why it is good to use an algorithm that, among other things, stores a seeded cryptographic one-way hash of the password, then compare the hashes, which will always be of the same length.

Exemple de code vulnérable

Vulnerable Python

When the attacker tries their own values, they can first try strings of various length. When they find a string of the right length, the computation will take a bit longer, because the for loop will run at least once. Additionally, with this code, the attacker can possibly learn one character of the password at a time, because when they guess the first character right, the computation will take longer than a wrong guesses. Such an attack can break even the most sophisticated password with a few hundred guesses.

Vulnérable Python 
def validate_password(actual_pw, typed_pw): 
  		if len(actual_pw) <> len(typed_pw): 
  			return 0
  		for i in len(actual_pw): 
  			if actual_pw[i] <> typed_pw[i]: 
  				return 0
  		return 1
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-385

  • Architecture and Design Whenever possible, specify implementation strategies that do not introduce time variances in operations.
  • Implementation Often one can artificially manipulate the time which operations take or -- when operations occur -- can remove information from the attacker.
  • Implementation It is reasonable to add artificial or random delays so that the amount of CPU time consumed is independent of the action being taken by the application.
Signaux de détection

How to detect CWE-385

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-385 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-385 ?

A covert timing channel is a security flaw where an attacker can deduce secret information by observing how long certain operations take to execute. Instead of directly reading data, they analyze timing variations in system behavior to infer protected details.

Quelle est la gravité de CWE-385 ?

MITRE évalue la probabilité d'exploitation comme Moyenne — l'exploitation est réaliste mais nécessite généralement des conditions spécifiques.

Quels langages ou plateformes sont affectés par CWE-385 ?

MITRE n'a pas spécifié les plateformes affectées pour ce CWE — il peut s'appliquer à la plupart des stacks applicatives.

Comment puis-je prévenir CWE-385 ?

Whenever possible, specify implementation strategies that do not introduce time variances in operations. Often one can artificially manipulate the time which operations take or -- when operations occur -- can remove information from the attacker.

Comment Plexicus détecte et corrige CWE-385 ?

Le moteur SAST de Plexicus reconnaît la signature de flux de données de CWE-385 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-385 ?

MITRE publie la définition canonique à https://cwe.mitre.org/data/definitions/385.html. Vous pouvez également consulter la documentation OWASP et NIST pour des conseils adjacents.

Faiblesses associées

Weaknesses related to CWE-385

CWE-514 Parent

Covert Channel

A covert channel is a hidden communication path that allows data to be transmitted in a way that bypasses the system's intended security…

CWE-515 Frère

Covert Storage Channel

A covert storage channel is a type of security flaw where one process secretly encodes data into a shared system resource (like a file,…

Ressources

Further reading

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