CWE-749 Base Incomplet Low likelihood

Exposed Dangerous Method or Function

This vulnerability occurs when a software component exposes an API or interface containing a high-risk function that lacks proper access controls, allowing unauthorized actors to trigger it.

Définition

What is CWE-749?

This vulnerability occurs when a software component exposes an API or interface containing a high-risk function that lacks proper access controls, allowing unauthorized actors to trigger it.
Exposing an unsafe function through a public interface creates a flexible attack surface. The danger stems not from the function itself, but from who can access it. Attackers can exploit this to trigger unintended behaviors—like file deletion, system commands, or data corruption—depending on what the exposed method does. This pattern applies broadly across technologies, including ActiveX controls, Java methods, IOCTLs, and REST API endpoints. The exposure typically happens in two scenarios: either the function was never meant to be publicly accessible during design, or it was intended only for a specific, trusted client (like a single website) but was improperly scoped. In both cases, the core failure is missing or inadequate authorization checks that should restrict access to privileged or internal operations.
Impact réel

Real-world CVEs caused by CWE-749

  • CVE-2007-6382

    arbitrary Java code execution via exposed method

  • CVE-2007-1112

    security tool ActiveX control allows download or upload of files

Comment les attaquants l'exploitent

Parcours de l'attaquant étape par étape

  1. 1

    In the following Java example the method removeDatabase will delete the database with the name specified in the input parameter.

  2. 2

    The method in this example is declared public and therefore is exposed to any class in the application. Deleting a database should be considered a critical operation within an application and access to this potentially dangerous method should be restricted. Within Java this can be accomplished simply by declaring the method private thereby exposing it only to the enclosing class as in the following example.

  3. 3

    These Android and iOS applications intercept URL loading within a WebView and perform special actions if a particular URL scheme is used, thus allowing the Javascript within the WebView to communicate with the application:

  4. 4

    A call into native code can then be initiated by passing parameters within the URL:

  5. 5

    Because the application does not check the source, a malicious website loaded within this WebView has the same access to the API as a trusted site.

Exemple de code vulnérable

Vulnerable Java

In the following Java example the method removeDatabase will delete the database with the name specified in the input parameter.

Vulnérable Java 
public void removeDatabase(String databaseName) {
  		try {
  				Statement stmt = conn.createStatement();
  				stmt.execute("DROP DATABASE " + databaseName);
  		} catch (SQLException ex) {...}
  }
Charge utile de l'attaquant

A call into native code can then be initiated by passing parameters within the URL:

Charge utile de l'attaquant JavaScript 
window.location = examplescheme://method?parameter=value
Exemple de code sécurisé

Secure Java

The method in this example is declared public and therefore is exposed to any class in the application. Deleting a database should be considered a critical operation within an application and access to this potentially dangerous method should be restricted. Within Java this can be accomplished simply by declaring the method private thereby exposing it only to the enclosing class as in the following example.

Sécurisé Java 
private void removeDatabase(String databaseName) {
  		try {
  				Statement stmt = conn.createStatement();
  				stmt.execute("DROP DATABASE " + databaseName);
  		} catch (SQLException ex) {...}
  		}
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-749

  • Architecture and Design If you must expose a method, make sure to perform input validation on all arguments, limit access to authorized parties, and protect against all possible vulnerabilities.
  • Architecture and Design / Implementation Identify all exposed functionality. Explicitly list all functionality that must be exposed to some user or set of users. Identify which functionality may be: - accessible to all users - restricted to a small set of privileged users - prevented from being directly accessible at all Ensure that the implemented code follows these expectations. This includes setting the appropriate access modifiers where applicable (public, private, protected, etc.) or not marking ActiveX controls safe-for-scripting.
Signaux de détection

How to detect CWE-749

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-749 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-749 ?

This vulnerability occurs when a software component exposes an API or interface containing a high-risk function that lacks proper access controls, allowing unauthorized actors to trigger it.

Quelle est la gravité de CWE-749 ?

MITRE évalue la probabilité d'exploitation comme Faible — l'exploitation est rare, mais la faiblesse doit tout de même être corrigée lorsqu'elle est découverte.

Quels langages ou plateformes sont affectés par CWE-749 ?

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-749 ?

If you must expose a method, make sure to perform input validation on all arguments, limit access to authorized parties, and protect against all possible vulnerabilities. Identify all exposed functionality. Explicitly list all functionality that must be exposed to some user or set of users. Identify which functionality may be: - accessible to all users - restricted to a small set of privileged users - prevented from being directly accessible at all Ensure that the implemented code follows…

Comment Plexicus détecte et corrige CWE-749 ?

Le moteur SAST de Plexicus reconnaît la signature de flux de données de CWE-749 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-749 ?

MITRE publie la définition canonique à https://cwe.mitre.org/data/definitions/749.html. Vous pouvez également consulter la documentation OWASP et NIST pour des conseils adjacents.

Faiblesses associées

Weaknesses related to CWE-749

CWE-284 Parent

Improper Access Control

The software fails to properly limit who can access a resource, allowing unauthorized users or systems to interact with it.

CWE-1191 Frère

On-Chip Debug and Test Interface With Improper Access Control

This vulnerability occurs when a hardware chip's debug or test interface (like JTAG) lacks proper access controls. Without correct…

CWE-1220 Frère

Insufficient Granularity of Access Control

This vulnerability occurs when a system's access controls are too broad, allowing unauthorized users or processes to read or modify…

CWE-1224 Frère

Improper Restriction of Write-Once Bit Fields

This vulnerability occurs when hardware write-once protection mechanisms, often called 'sticky bits,' are incorrectly implemented,…

CWE-1231 Frère

Improper Prevention of Lock Bit Modification

This vulnerability occurs when hardware or firmware uses a lock bit to protect critical system registers or memory regions, but fails to…

CWE-1233 Frère

Security-Sensitive Hardware Controls with Missing Lock Bit Protection

This vulnerability occurs when a hardware device uses a lock bit to protect critical configuration registers, but the lock fails to…

CWE-1252 Frère

CPU Hardware Not Configured to Support Exclusivity of Write and Execute Operations

This vulnerability occurs when a CPU's hardware is not set up to enforce a strict separation between writing data to memory and executing…

CWE-1257 Frère

Improper Access Control Applied to Mirrored or Aliased Memory Regions

This vulnerability occurs when a hardware design maps the same physical memory to multiple addresses (aliasing or mirroring) but fails to…

CWE-1259 Frère

Improper Restriction of Security Token Assignment

This vulnerability occurs when a System-on-a-Chip (SoC) fails to properly secure its Security Token mechanism. These tokens control which…

Ressources

Further reading

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