CWE-143 Variante Brouillon

Improper Neutralization of Record Delimiters

This vulnerability occurs when an application fails to properly sanitize or escape special characters that function as record separators in data streams. When untrusted input containing these…

Définition

What is CWE-143?

This vulnerability occurs when an application fails to properly sanitize or escape special characters that function as record separators in data streams. When untrusted input containing these delimiters is passed to a downstream system, it can corrupt data structures, cause misinterpretation of records, or trigger unauthorized actions.

Imagine your application accepts user input—like a form field for a name or address—and later packages that data into a structured format like a CSV file, a log entry, or a protocol message. If an attacker submits input containing a record delimiter (such as a newline, pipe character, or custom separator), and your code doesn't neutralize it, that input can break the expected record boundaries. The downstream parser, whether it's a database, a reporting tool, or another service, will then misinterpret where one record ends and the next begins, leading to data corruption, injection of false records, or logic errors. In practice, this flaw allows data to escape its intended context. For example, a single input field could be parsed as multiple separate records, or critical delimiters could be missing, causing entire records to be merged or skipped. To prevent this, you must always validate and sanitize input by escaping or removing delimiter characters based on the specific data format and context before processing or transmitting the data.

Impact réel

Real-world CVEs caused by CWE-143

CVE-2004-1982

Carriage returns in subject field allow adding new records to data file.
CVE-2001-0527

Attacker inserts carriage returns and "|" field separator characters to add new user/privileges.

Comment les attaquants l'exploitent

Parcours de l'attaquant étape par étape

1
Identifier un chemin de code qui traite des entrées non fiables sans validation.
2
Élaborer une charge utile qui exploite le comportement non sécurisé — injection, traversal, débordement ou abus de logique.
3
Délivrer la charge utile via une requête normale et observer la réaction de l'application.
4
Itérer jusqu'à ce que la réponse divulgue des données, exécute le code de l'attaquant ou élève les privilèges.

Exemple de code vulnérable

Vulnerable pseudo

MITRE n'a pas publié d'exemple de code pour ce CWE. Le motif ci-dessous est illustratif — voir Ressources pour les références canoniques.

Vulnérable pseudo

// Example pattern — see MITRE for the canonical references.
function handleRequest(input) {
  // Untrusted input flows directly into the sensitive sink.
  return executeUnsafe(input);
}

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-143

Developers should anticipate that record delimiters will be injected/removed/manipulated in the input vectors of their product. Use an appropriate combination of denylists and allowlists to ensure only valid, expected and appropriate input is processed by the system.
Implementation Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does. When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, "boat" may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as "red" or "blue." Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code's environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright.
Implementation While it is risky to use dynamically-generated query strings, code, or commands that mix control and data together, sometimes it may be unavoidable. Properly quote arguments and escape any special characters within those arguments. The most conservative approach is to escape or filter all characters that do not pass an extremely strict allowlist (such as everything that is not alphanumeric or white space). If some special characters are still needed, such as white space, wrap each argument in quotes after the escaping/filtering step. Be careful of argument injection (CWE-88).
Implementation Inputs should be decoded and canonicalized to the application's current internal representation before being validated (CWE-180). Make sure that the application does not decode the same input twice (CWE-174). Such errors could be used to bypass allowlist validation schemes by introducing dangerous inputs after they have been checked.

Signaux de détection

How to detect CWE-143

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-143 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-143 ?

Quelle est la gravité de CWE-143 ?

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-143 ?

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-143 ?

Developers should anticipate that record delimiters will be injected/removed/manipulated in the input vectors of their product. Use an appropriate combination of denylists and allowlists to ensure only valid, expected and appropriate input is processed by the system. Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications,…

Comment Plexicus détecte et corrige CWE-143 ?

Le moteur SAST de Plexicus reconnaît la signature de flux de données de CWE-143 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-143 ?

MITRE publie la définition canonique à https://cwe.mitre.org/data/definitions/143.html. Vous pouvez également consulter la documentation OWASP et NIST pour des conseils adjacents.

Faiblesses associées

Weaknesses related to CWE-143

CWE-140 Parent

Improper Neutralization of Delimiters

This vulnerability occurs when an application fails to properly handle or sanitize delimiter characters within data inputs, allowing them…

CWE-141 Frère

Improper Neutralization of Parameter/Argument Delimiters

This vulnerability occurs when an application fails to properly sanitize special characters that act as delimiters in data being passed…

CWE-142 Frère

Improper Neutralization of Value Delimiters

This vulnerability occurs when an application fails to properly sanitize or escape special characters that act as data separators…

CWE-144 Frère

Improper Neutralization of Line Delimiters

This vulnerability occurs when an application fails to properly sanitize or escape line break characters (like newline or carriage return)…

CWE-145 Frère

Improper Neutralization of Section Delimiters

This vulnerability occurs when an application fails to properly sanitize or validate special characters that act as section delimiters in…

CWE-146 Frère

Improper Neutralization of Expression/Command Delimiters

This vulnerability occurs when an application fails to properly sanitize input that contains special characters used as delimiters in…

Ressources

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