CWE-90 Base Brouillon

Improper Neutralization of Special Elements used in an LDAP Query ('LDAP Injection')

This vulnerability occurs when an application builds an LDAP query using untrusted user input without properly sanitizing it. An attacker can inject special characters or commands to alter the…

Définition

What is CWE-90?

This vulnerability occurs when an application builds an LDAP query using untrusted user input without properly sanitizing it. An attacker can inject special characters or commands to alter the query's logic, potentially gaining unauthorized access to, modifying, or extracting sensitive directory information.

LDAP Injection happens much like SQL injection, but targets Lightweight Directory Access Protocol queries. When user input from a form, URL parameter, or API request is directly concatenated into an LDAP search filter (like `(cn=` + userInput + `)`), an attacker can insert characters like `*`, `(`, `)`, `\`, or `null` to break the query's structure. This allows them to bypass authentication, escalate privileges, or dump the entire contents of the directory by creating filters like `*)(uid=*))(|(uid=*` that always return results. To prevent this, developers should never construct LDAP filters by simple string concatenation. Instead, use parameterized queries or the encoding functions provided by your LDAP library (like `escapeLDAPSearchFilter` in Java or `ldap_escape` in PHP) to properly neutralize special characters. Always apply the principle of least privilege to the LDAP binding account and validate all input against a strict allow-list of expected characters before it reaches the query builder.

Impact réel

Real-world CVEs caused by CWE-90

CVE-2021-41232

Chain: authentication routine in Go-based agile development product does not escape user name (CWE-116), allowing LDAP injection (CWE-90)
CVE-2005-2301

Server does not properly escape LDAP queries, which allows remote attackers to cause a DoS and possibly conduct an LDAP injection attack.

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 Java

The code below constructs an LDAP query using user input address data:

Vulnérable Java

context = new InitialDirContext(env);
  String searchFilter = "StreetAddress=" + address;
  NamingEnumeration answer = context.search(searchBase, searchFilter, searchCtls);

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-90

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.

Signaux de détection

How to detect CWE-90

Automated Static Analysis High

Automated static analysis, commonly referred to as Static Application Security Testing (SAST), can find some instances of this weakness by analyzing source code (or binary/compiled code) without having to execute it. Typically, this is done by building a model of data flow and control flow, then searching for potentially-vulnerable patterns that connect "sources" (origins of input) with "sinks" (destinations where the data interacts with external components, a lower layer such as the OS, etc.)

Correction automatique Plexicus

Plexicus détecte automatiquement CWE-90 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-90 ?

Quelle est la gravité de CWE-90 ?

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-90 ?

MITRE lists the following affected platforms: Database Server.

Comment puis-je prévenir CWE-90 ?

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…

Comment Plexicus détecte et corrige CWE-90 ?

Le moteur SAST de Plexicus reconnaît la signature de flux de données de CWE-90 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-90 ?

MITRE publie la définition canonique à https://cwe.mitre.org/data/definitions/90.html. Vous pouvez également consulter la documentation OWASP et NIST pour des conseils adjacents.

Faiblesses associées

Weaknesses related to CWE-90

CWE-943 Parent

Improper Neutralization of Special Elements in Data Query Logic

This vulnerability occurs when an application builds a query for a data store (like a database) but fails to properly sanitize…

CWE-643 Frère

Improper Neutralization of Data within XPath Expressions ('XPath Injection')

XPath Injection occurs when an application uses unvalidated user input to build an XPath query for an XML database. Without proper…

CWE-652 Frère

Improper Neutralization of Data within XQuery Expressions ('XQuery Injection')

XQuery Injection occurs when an application uses unvalidated user input to build an XQuery expression for querying an XML database.…

CWE-89 Frère

Improper Neutralization of Special Elements used in an SQL Command ('SQL Injection')

SQL Injection occurs when an application builds a database query using untrusted user input without properly sanitizing it. This allows an…

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