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CWE-290 Base Incomplet
Authentication Bypass by Spoofing
This weakness occurs when an application's authentication system can be tricked into accepting forged or manipulated credentials, allowing unauthorized access without proper verification.
Définition
What is CWE-290?
This weakness occurs when an application's authentication system can be tricked into accepting forged or manipulated credentials, allowing unauthorized access without proper verification.
Authentication bypass by spoofing happens when an application fails to properly verify the source or integrity of authentication data. Instead of robustly checking credentials, the system might accept falsified information from network packets, certificates, session tokens, or identity claims. This allows attackers to impersonate legitimate users by crafting fake authentication artifacts that the flawed validation logic incorrectly approves.
Common root causes include trusting easily forged data like IP addresses or HTTP headers for identity, using weak cryptographic signatures, or failing to validate the entire authentication chain. To prevent this, developers must implement complete credential verification using cryptographically secure methods, never rely on client-supplied data alone for identity, and ensure all authentication tokens are properly signed and validated on the server side.
Impact réel
Real-world CVEs caused by CWE-290
-
S-bus functionality in a home automation product performs access control using an IP allowlist, which can be bypassed by a forged IP address.
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VOIP product allows authentication bypass using 127.0.0.1 in the Host header.
Comment les attaquants l'exploitent
Parcours de l'attaquant étape par étape
- 1
The following code authenticates users.
- 2
The authentication mechanism implemented relies on an IP address for source validation. If an attacker is able to spoof the IP, they may be able to bypass the authentication mechanism.
- 3
Both of these examples check if a request is from a trusted address before responding to the request.
- 4
The code only verifies the address as stored in the request packet. An attacker can spoof this address, thus impersonating a trusted client.
- 5
The following code samples use a DNS lookup in order to decide whether or not an inbound request is from a trusted host. If an attacker can poison the DNS cache, they can gain trusted status.
Exemple de code vulnérable
Vulnerable Java
The following code authenticates users.
String sourceIP = request.getRemoteAddr();
if (sourceIP != null && sourceIP.equals(APPROVED_IP)) {
authenticated = true;
} Exemple de code sécurisé
Secure 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-290
- 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-290
Exécuter des tests de sécurité applicative dynamique (DAST) contre le point de terminaison en ligne.
Surveiller les journaux runtime pour détecter des traces d'exception inhabituelles, des entrées malformées ou des tentatives de contournement d'autorisation.
Revue de code : signaler tout nouveau code qui traite les entrées de cette surface sans utiliser les helpers du framework validés.
CWE-290
Don't catalog this weakness. Prove it's reachable.
Plexicus turns CWE catalogs into evidence: every CWE-pattern is matched against your real code graph, reach is proven on a sandbox clone, and verified findings ship as reviewed PRs.
Questions fréquentes Qu'est-ce que CWE-290 ?
Quelle est la gravité de CWE-290 ?
Quels langages ou plateformes sont affectés par CWE-290 ?
Comment puis-je prévenir CWE-290 ?
Comment Plexicus détecte et corrige CWE-290 ?
Où puis-je en savoir plus sur CWE-290 ?
Frequently asked questions
Qu'est-ce que CWE-290 ?
This weakness occurs when an application's authentication system can be tricked into accepting forged or manipulated credentials, allowing unauthorized access without proper verification.
Quelle est la gravité de CWE-290 ?
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-290 ?
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-290 ?
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-290 ?
Le moteur SAST de Plexicus reconnaît la signature de flux de données de CWE-290 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-290 ?
MITRE publie la définition canonique à https://cwe.mitre.org/data/definitions/290.html. Vous pouvez également consulter la documentation OWASP et NIST pour des conseils adjacents.
Faiblesses associées
Weaknesses related to CWE-290
CWE-1390 Parent
Weak Authentication
This vulnerability occurs when a system's login or identity verification process is too easy to bypass or fool. While it attempts to check…
CWE-1391 Frère
Use of Weak Credentials
This vulnerability occurs when a system relies on weak authentication credentials—like default passwords, hard-coded keys, or easily…
CWE-262 Frère
Not Using Password Aging
This vulnerability occurs when a system lacks password expiration policies, allowing users to keep the same password indefinitely.
CWE-263 Frère
Password Aging with Long Expiration
The system enforces password changes, but the time allowed between changes is excessively long, weakening security.
CWE-289 Frère
Authentication Bypass by Alternate Name
This vulnerability occurs when a system checks access based on a resource or user name, but fails to account for all the different names…
CWE-294 Frère
Authentication Bypass by Capture-replay
This vulnerability occurs when an attacker can intercept and record legitimate authentication traffic, then replay it later to gain…
CWE-301 Frère
Reflection Attack in an Authentication Protocol
A reflection attack is a flaw in mutual authentication protocols that allows an attacker to impersonate a legitimate user without knowing…
CWE-302 Frère
Authentication Bypass by Assumed-Immutable Data
This vulnerability occurs when an authentication system incorrectly treats certain data as unchangeable, when in fact an attacker can…
CWE-303 Frère
Incorrect Implementation of Authentication Algorithm
This weakness occurs when a developer implements a standard authentication algorithm, but makes critical mistakes in the code that cause…
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