CWE-433: Unparsed Raw Web Content Delivery

Definition

What is CWE-433?

This vulnerability occurs when a web application stores unprocessed files—like configuration scripts or raw source code—in publicly accessible directories using file extensions the server doesn't recognize.

Web servers are configured to process certain file types (like .php or .asp) before sending them to users. When you place files with extensions like .inc, .config, .bak, or .old in a web-accessible folder, and the server doesn't have a handler for them, it treats them as plain text. The server then delivers the raw, unprocessed file content directly to anyone who requests it. This becomes critical when these files contain sensitive information such as database connection strings, API keys, internal comments, or backend logic. Attackers can easily discover and download these files, bypassing any intended security controls. To prevent this, always store supporting code and configuration files outside the web root or use server rules to explicitly block access to non-standard extensions.

Auswirkungen in der Praxis

Real-world CVEs caused by CWE-433

CVE-2002-1886

".inc" file stored under web document root and returned unparsed by the server
CVE-2002-2065

".inc" file stored under web document root and returned unparsed by the server
CVE-2005-2029

".inc" file stored under web document root and returned unparsed by the server
CVE-2001-0330

direct request to .pl file leaves it unparsed
CVE-2002-0614

.inc file
CVE-2004-2353

unparsed config.conf file
CVE-2007-3365

Chain: uppercase file extensions causes web server to return script source code instead of executing the script.

Wie Angreifer es ausnutzen

Angreiferpfad Schritt für Schritt

1
The following code uses an include file to store database credentials:
2
database.inc
3
login.php
4
If the server does not have an explicit handler set for .inc files it may send the contents of database.inc to an attacker without pre-processing, if the attacker requests the file directly. This will expose the database name and password.

Verwundbares Codebeispiel

Vulnerable PHP

database.inc

Verwundbar PHP

<?php
  $dbName = 'usersDB';
  $dbPassword = 'skjdh#67nkjd3$3$';
  ?>

Sicheres Codebeispiel

Secure pseudo

Sicher 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.

Präventions-Checkliste

How to prevent CWE-433

Architecture and Design Perform a type check before interpreting files.
Architecture and Design Do not store sensitive information in files which may be misinterpreted.

Erkennungssignale

How to detect CWE-433

SAST High

Führe statische Analyse (SAST) auf der Codebasis aus und suche im Datenfluss nach dem unsicheren Muster.

DAST Moderate

Führe dynamische Application-Security-Tests gegen den Live-Endpoint aus.

Runtime Moderate

Beobachte Runtime-Logs auf ungewöhnliche Exception-Traces, fehlerhafte Eingaben oder Versuche, Autorisierung zu umgehen.

Code review Moderate

Code Review: Markiere jeden neuen Code, der Eingaben von dieser Oberfläche ohne validierte Framework-Helper verarbeitet.

CWE-433

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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.

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Häufig gestellte Fragen

Frequently asked questions

Was ist CWE-433?

This vulnerability occurs when a web application stores unprocessed files—like configuration scripts or raw source code—in publicly accessible directories using file extensions the server doesn't recognize.

Wie gravierend ist CWE-433?

MITRE hat für diese Schwachstelle keine Exploit-Wahrscheinlichkeit veröffentlicht. Behandle sie als mittlere Auswirkung, bis dein Threat Model anderes belegt.

Welche Sprachen oder Plattformen sind von CWE-433 betroffen?

MITRE hat für diese CWE keine betroffenen Plattformen spezifiziert — sie kann in den meisten Anwendungs-Stacks auftreten.

Wie kann ich CWE-433 verhindern?

Perform a type check before interpreting files. Do not store sensitive information in files which may be misinterpreted.

Wie erkennt und behebt Plexicus CWE-433?

Die SAST-Engine von Plexicus erkennt die Datenfluss-Signatur von CWE-433 bei jedem Commit. Bei einem Treffer öffnet unser Codex-Remedium-Agent einen Fix-PR mit korrigiertem Code, Tests und einer einzeiligen Zusammenfassung für den Reviewer.

Wo erfahre ich mehr über CWE-433?

MITRE veröffentlicht die kanonische Definition unter https://cwe.mitre.org/data/definitions/433.html. Für ergänzende Hinweise kannst du auch die OWASP- und NIST-Dokumentation heranziehen.

Verwandte Schwachstellen

Weaknesses related to CWE-433

CWE-219 Parent

Storage of File with Sensitive Data Under Web Root

This vulnerability occurs when an application saves sensitive files, such as configuration data or private keys, inside the web server's…

Ressourcen

Bereit zu validieren, was zählt.

Plexicus ist Proof-Driven AppSec: validierte Funde, kontextuelles Verständnis und geprüfte Remediation — in Evidenz verankert, mit Ihnen gescoped.

Pentest buchen

Unparsed Raw Web Content Delivery