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CWE-130 Base Incomplet
Improper Handling of Length Parameter Inconsistency
This vulnerability occurs when a program reads a structured data packet or message but fails to properly validate that the declared length field matches the actual amount of data provided.
Définition
What is CWE-130?
This vulnerability occurs when a program reads a structured data packet or message but fails to properly validate that the declared length field matches the actual amount of data provided.
Attackers exploit this flaw by deliberately sending data where the stated length is incorrect—either longer or shorter than the real payload. This inconsistency tricks the application's parsing logic, often leading to catastrophic security failures like buffer overflows, memory corruption, or the processing of garbage data as if it were legitimate instructions.
In practice, an attacker might use a manipulated length field to inject massive amounts of data beyond allocated buffers or to carefully craft input that alters critical application state. The core defense is for developers to always independently calculate or strictly verify data lengths during parsing, never trusting the user-supplied length parameter alone before processing the associated data block.
Impact réel
Real-world CVEs caused by CWE-130
-
Chain: "Heartbleed" bug receives an inconsistent length parameter (CWE-130) enabling an out-of-bounds read (CWE-126), returning memory that could include private cryptographic keys and other sensitive data.
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Web application firewall consumes excessive memory when an HTTP request contains a large Content-Length value but no POST data.
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Buffer overflow in internal string handling routine allows remote attackers to execute arbitrary commands via a length argument of zero or less, which disables the length check.
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Web server allows remote attackers to cause a denial of service via an HTTP request with a content-length value that is larger than the size of the request, which prevents server from timing out the connection.
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Service does not properly check the specified length of a cookie, which allows remote attackers to execute arbitrary commands via a buffer overflow, or brute force authentication by using a short cookie length.
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Traffic analyzer allows remote attackers to cause a denial of service and possibly execute arbitrary code via invalid IPv4 or IPv6 prefix lengths, possibly triggering a buffer overflow.
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Chat client allows remote attackers to cause a denial of service or execute arbitrary commands via a JPEG image containing a comment with an illegal field length of 1.
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Server allows remote attackers to cause a denial of service and possibly execute arbitrary code via a negative Content-Length HTTP header field causing a heap-based buffer overflow.
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 C
In the following C/C++ example the method processMessageFromSocket() will get a message from a socket, placed into a buffer, and will parse the contents of the buffer into a structure that contains the message length and the message body. A for loop is used to copy the message body into a local character string which will be passed to another method for processing.
int processMessageFromSocket(int socket) {
int success;
char buffer[BUFFER_SIZE];
char message[MESSAGE_SIZE];
```
// get message from socket and store into buffer*
*//Ignoring possibliity that buffer > BUFFER_SIZE*
if (getMessage(socket, buffer, BUFFER_SIZE) > 0) {
```
```
// place contents of the buffer into message structure*
ExMessage *msg = recastBuffer(buffer);
*// copy message body into string for processing*
int index;
for (index = 0; index < msg->msgLength; index++) {
```
message[index] = msg->msgBody[index];
}
message[index] = '\0';
```
// process message*
success = processMessage(message);}
return success;} 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-130
- Implementation When processing structured incoming data containing a size field followed by raw data, ensure that you identify and resolve any inconsistencies between the size field and the actual size of the data.
- Implementation Do not let the user control the size of the buffer.
- Implementation Validate that the length of the user-supplied data is consistent with the buffer size.
Signaux de détection
How to detect CWE-130
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-130
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-130 ?
Quelle est la gravité de CWE-130 ?
Quels langages ou plateformes sont affectés par CWE-130 ?
Comment puis-je prévenir CWE-130 ?
Comment Plexicus détecte et corrige CWE-130 ?
Où puis-je en savoir plus sur CWE-130 ?
Frequently asked questions
Qu'est-ce que CWE-130 ?
This vulnerability occurs when a program reads a structured data packet or message but fails to properly validate that the declared length field matches the actual amount of data provided.
Quelle est la gravité de CWE-130 ?
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-130 ?
MITRE lists the following affected platforms: C, C++.
Comment puis-je prévenir CWE-130 ?
When processing structured incoming data containing a size field followed by raw data, ensure that you identify and resolve any inconsistencies between the size field and the actual size of the data. Do not let the user control the size of the buffer.
Comment Plexicus détecte et corrige CWE-130 ?
Le moteur SAST de Plexicus reconnaît la signature de flux de données de CWE-130 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-130 ?
MITRE publie la définition canonique à https://cwe.mitre.org/data/definitions/130.html. Vous pouvez également consulter la documentation OWASP et NIST pour des conseils adjacents.
Faiblesses associées
Weaknesses related to CWE-130
CWE-240 Parent
Improper Handling of Inconsistent Structural Elements
This vulnerability occurs when a system fails to properly manage situations where related data structures or elements should match but are…
CWE-805 Peut précéder
Buffer Access with Incorrect Length Value
This vulnerability occurs when software reads from or writes to a buffer using a loop or sequential operation, but mistakenly calculates…
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