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.)
CWE-379 Base Incomplet
Creation of Temporary File in Directory with Insecure Permissions
This vulnerability occurs when an application creates a temporary file in a directory that is too permissive, allowing unauthorized users or processes to see, access, or manipulate the file.
Définition
What is CWE-379?
This vulnerability occurs when an application creates a temporary file in a directory that is too permissive, allowing unauthorized users or processes to see, access, or manipulate the file.
When a temporary file is placed in a directory with loose permissions (like world-readable or world-writable), other users or system actors can detect its presence. This simple act of discovery reveals which application created the file, offering a window into what the user is currently doing. Attackers can correlate this information with running processes to infer sensitive user activity, turning a seemingly minor information leak into a serious privacy breach.
This issue is more than just a file access problem; it's an information exposure flaw that can enable targeted attacks. By knowing which application is in use, an attacker gains critical context to craft further exploits, potentially escalating privileges or accessing confidential data. Developers must ensure temporary files are created in secure, private locations with strict access controls to prevent this form of reconnaissance.
Impact réel
Real-world CVEs caused by CWE-379
-
A hotkey daemon written in Rust creates a domain socket file underneath /tmp, which is accessible by any user.
-
A Java-based application for a rapid-development framework uses File.createTempFile() to create a random temporary file with insecure default permissions.
Comment les attaquants l'exploitent
Parcours de l'attaquant étape par étape
- 1
In the following code examples a temporary file is created and written to. After using the temporary file, the file is closed and deleted from the file system.
- 2
However, within this C/C++ code the method tmpfile() is used to create and open the temp file. The tmpfile() method works the same way as the fopen() method would with read/write permission, allowing attackers to read potentially sensitive information contained in the temp file or modify the contents of the file.
- 3
Similarly, the createTempFile() method used in the Java code creates a temp file that may be readable and writable to all users.
- 4
Additionally both methods used above place the file into a default directory. On UNIX systems the default directory is usually "/tmp" or "/var/tmp" and on Windows systems the default directory is usually "C:\\Windows\\Temp", which may be easily accessible to attackers, possibly enabling them to read and modify the contents of the temp file.
Exemple de code vulnérable
Vulnerable C
In the following code examples a temporary file is created and written to. After using the temporary file, the file is closed and deleted from the file system.
FILE *stream;
if( (stream = tmpfile()) == NULL ) {
perror("Could not open new temporary file\n");
return (-1);
}
```
// write data to tmp file*
...
// remove tmp file
rmtmp(); 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-379
- Requirements Many contemporary languages have functions which properly handle this condition. Older C temp file functions are especially susceptible.
- Implementation Try to store sensitive tempfiles in a directory which is not world readable -- i.e., per-user directories.
- Implementation Avoid using vulnerable temp file functions.
Signaux de détection
How to detect CWE-379
Plexicus détecte automatiquement CWE-379 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.
Questions fréquentes Qu'est-ce que CWE-379 ?
Quelle est la gravité de CWE-379 ?
Quels langages ou plateformes sont affectés par CWE-379 ?
Comment puis-je prévenir CWE-379 ?
Comment Plexicus détecte et corrige CWE-379 ?
Où puis-je en savoir plus sur CWE-379 ?
Frequently asked questions
Qu'est-ce que CWE-379 ?
This vulnerability occurs when an application creates a temporary file in a directory that is too permissive, allowing unauthorized users or processes to see, access, or manipulate the file.
Quelle est la gravité de CWE-379 ?
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-379 ?
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-379 ?
Many contemporary languages have functions which properly handle this condition. Older C temp file functions are especially susceptible. Try to store sensitive tempfiles in a directory which is not world readable -- i.e., per-user directories.
Comment Plexicus détecte et corrige CWE-379 ?
Le moteur SAST de Plexicus reconnaît la signature de flux de données de CWE-379 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-379 ?
MITRE publie la définition canonique à https://cwe.mitre.org/data/definitions/379.html. Vous pouvez également consulter la documentation OWASP et NIST pour des conseils adjacents.
Faiblesses associées
Weaknesses related to CWE-379
CWE-377 Parent
Insecure Temporary File
This vulnerability occurs when an application creates temporary files with insecure permissions or in predictable locations, allowing…
CWE-378 Frère
Creation of Temporary File With Insecure Permissions
This vulnerability occurs when a program creates a temporary file but sets its file permissions too loosely, allowing other users or…
Prêt quand vous l'êtes
Arrêtez de payer par développeur.
Commencez à fermer la boucle.
Plexicus est l'ASPM natif IA qui scanne, filtre, corrige, penteste et explique — de façon autonome. Développeurs illimités, dépôts illimités, actions IA à usage équitable. Vrai niveau gratuit, €269/mo annuel quand vous êtes prêt.