Führe statische Analyse (SAST) auf der Codebasis aus und suche im Datenfluss nach dem unsicheren Muster.
CWE-67 Variant Incomplete
Improper Handling of Windows Device Names
This vulnerability occurs when an application builds file paths from user input but fails to properly recognize or handle Windows reserved device names like AUX, CON, or COM1. Attackers can exploit…
Definition
What is CWE-67?
This vulnerability occurs when an application builds file paths from user input but fails to properly recognize or handle Windows reserved device names like AUX, CON, or COM1. Attackers can exploit this by submitting these special names, which typically causes the application to crash, hang, or leak sensitive information when it tries to access them as regular files.
Windows reserves certain filenames like AUX, CON, PRN, COM1, and LPT1 for internal device access. When an application accepts user-controlled input for filenames or paths without filtering these names, it may attempt to open a system device instead of a file. This often triggers unexpected errors, leading to application denial of service or revealing internal error details in logs or web responses.
Beyond crashes, this flaw can bypass security filters. If an application's validation logic doesn't block these reserved names, an attacker might upload a malicious file disguised as a device name, or inject a device path into a URL parameter. This can disrupt file processing routines, expose stack traces or configuration data, and in some cases, be combined with other weaknesses to execute arbitrary commands.
Auswirkungen in der Praxis
Real-world CVEs caused by CWE-67
-
Server allows remote attackers to cause a denial of service via a series of requests to .JSP files that contain an MS-DOS device name.
-
Server allows remote attackers to cause a denial of service via an HTTP request for an MS-DOS device name.
-
Product allows remote attackers to use MS-DOS device names in HTTP requests to cause a denial of service or obtain the physical path of the server.
-
Server allows remote attackers to cause a denial of service via a URL that contains an MS-DOS device name.
-
Server allows a remote attacker to create a denial of service via a URL request which includes a MS-DOS device name.
-
Microsoft Windows 9x operating systems allow an attacker to cause a denial of service via a pathname that includes file device names, aka the "DOS Device in Path Name" vulnerability.
-
Server allows remote attackers to determine the physical path of the server via a URL containing MS-DOS device names.
-
Product does not properly handle files whose names contain reserved MS-DOS device names, which can allow malicious code to bypass detection when it is installed, copied, or executed.
Wie Angreifer es ausnutzen
Angreiferpfad Schritt für Schritt
- 1
Identifiziere einen Codepfad, der nicht vertrauenswürdige Eingaben ohne Validierung verarbeitet.
- 2
Erzeuge eine Payload, die das unsichere Verhalten auslöst — Injection, Traversal, Overflow oder Logik-Missbrauch.
- 3
Liefere die Payload über einen normalen Request aus und beobachte die Reaktion der Anwendung.
- 4
Iteriere, bis die Antwort Daten preisgibt, Angreifer-Code ausführt oder Berechtigungen eskaliert.
Verwundbares Codebeispiel
Vulnerable pseudo
MITRE hat kein Codebeispiel für diese CWE veröffentlicht. Das untenstehende Muster ist illustrativ — kanonische Referenzen findest du unter Ressourcen.
// Example pattern — see MITRE for the canonical references.
function handleRequest(input) {
// Untrusted input flows directly into the sensitive sink.
return executeUnsafe(input);
} Sicheres Codebeispiel
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.
Präventions-Checkliste
How to prevent CWE-67
- Implementation Be familiar with the device names in the operating system where your system is deployed. Check input for these device names.
Erkennungssignale
How to detect CWE-67
Führe dynamische Application-Security-Tests gegen den Live-Endpoint aus.
Beobachte Runtime-Logs auf ungewöhnliche Exception-Traces, fehlerhafte Eingaben oder Versuche, Autorisierung zu umgehen.
Code Review: Markiere jeden neuen Code, der Eingaben von dieser Oberfläche ohne validierte Framework-Helper verarbeitet.
CWE-67
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.
Häufig gestellte Fragen Was ist CWE-67?
Wie gravierend ist CWE-67?
Welche Sprachen oder Plattformen sind von CWE-67 betroffen?
Wie kann ich CWE-67 verhindern?
Wie erkennt und behebt Plexicus CWE-67?
Wo erfahre ich mehr über CWE-67?
Frequently asked questions
Was ist CWE-67?
This vulnerability occurs when an application builds file paths from user input but fails to properly recognize or handle Windows reserved device names like AUX, CON, or COM1. Attackers can exploit this by submitting these special names, which typically causes the application to crash, hang, or leak sensitive information when it tries to access them as regular files.
Wie gravierend ist CWE-67?
MITRE stuft die Exploit-Wahrscheinlichkeit als hoch ein — diese Schwachstelle wird aktiv in freier Wildbahn ausgenutzt und sollte priorisiert behoben werden.
Welche Sprachen oder Plattformen sind von CWE-67 betroffen?
MITRE lists the following affected platforms: Windows.
Wie kann ich CWE-67 verhindern?
Be familiar with the device names in the operating system where your system is deployed. Check input for these device names.
Wie erkennt und behebt Plexicus CWE-67?
Die SAST-Engine von Plexicus erkennt die Datenfluss-Signatur von CWE-67 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-67?
MITRE veröffentlicht die kanonische Definition unter https://cwe.mitre.org/data/definitions/67.html. Für ergänzende Hinweise kannst du auch die OWASP- und NIST-Dokumentation heranziehen.
Verwandte Schwachstellen
Weaknesses related to CWE-67
CWE-66 Parent
Improper Handling of File Names that Identify Virtual Resources
This vulnerability occurs when software incorrectly processes a filename that points to a 'virtual' resource—like a device, pipe, or…
CWE-69 Sibling
Improper Handling of Windows ::DATA Alternate Data Stream
This vulnerability occurs when an application fails to properly secure or monitor Windows Alternate Data Streams (ADS), allowing them to…
CWE-72 Sibling
Improper Handling of Apple HFS+ Alternate Data Stream Path
This vulnerability occurs when software fails to correctly process HFS+ file system paths that point to alternate data streams, such as a…
Bereit, das Wesentliche zu validieren?
Bereit zu validieren, was zählt.
Plexicus ist Proof-Driven AppSec: validierte Funde, kontextuelles Verständnis und geprüfte Remediation — in Evidenz verankert, mit Ihnen gescoped.