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CWE-1023 Class Incomplete
Incomplete Comparison with Missing Factors
This weakness occurs when a program compares two items but fails to check all the necessary attributes that define their true relationship. The incomplete check can cause the software to treat…
Definition
What is CWE-1023?
This weakness occurs when a program compares two items but fails to check all the necessary attributes that define their true relationship. The incomplete check can cause the software to treat different items as identical or make incorrect security decisions.
Incomplete comparisons happen when a developer writes a check that only validates a subset of an object's or user's identity. For example, a system might authenticate a user by checking only a username without verifying the associated password or session token, or it might compare data objects using only an ID field while ignoring a critical 'type' or 'state' field. This creates a logical gap where two distinct entities can be incorrectly evaluated as equivalent.
This flaw directly undermines security and logic by allowing unauthorized access, privilege escalation, or data corruption. Attackers can exploit it by providing an entity that matches on the checked factors but differs maliciously on the unchecked ones. To prevent this, always ensure comparison functions validate every unique and security-relevant property that defines an entity's complete identity within that specific context.
Auswirkungen in der Praxis
Real-world CVEs caused by CWE-1023
-
PHP remote file inclusion in web application that filters "http" and "https" URLs, but not "ftp".
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Product does not prevent access to restricted directories due to partial string comparison with a public directory
Wie Angreifer es ausnutzen
Angreiferpfad Schritt für Schritt
- 1
Consider an application in which Truck objects are defined to be the same if they have the same make, the same model, and were manufactured in the same year.
- 2
Here, the equals() method only checks the make and model of the Truck objects, but the year of manufacture is not included.
- 3
This example defines a fixed username and password. The AuthenticateUser() function is intended to accept a username and a password from an untrusted user, and check to ensure that it matches the username and password. If the username and password match, AuthenticateUser() is intended to indicate that authentication succeeded.
- 4
In AuthenticateUser(), the strncmp() call uses the string length of an attacker-provided inPass parameter in order to determine how many characters to check in the password. So, if the attacker only provides a password of length 1, the check will only examine the first byte of the application's password before determining success.
- 5
As a result, this partial comparison leads to improper authentication (CWE-287).
Verwundbares Codebeispiel
Vulnerable Java
Consider an application in which Truck objects are defined to be the same if they have the same make, the same model, and were manufactured in the same year.
public class Truck {
private String make;
private String model;
private int year;
public boolean equals(Object o) {
if (o == null) return false;
if (o == this) return true;
if (!(o instanceof Truck)) return false;
Truck t = (Truck) o;
return (this.make.equals(t.getMake()) && this.model.equals(t.getModel()));
}
} Angreifer-Payload
Any of these passwords would still cause authentication to succeed for the "admin" user:
p
pa
pas
pass 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-1023
- Testing Thoroughly test the comparison scheme before deploying code into production. Perform positive testing as well as negative testing.
Erkennungssignale
How to detect CWE-1023
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.
Plexicus erkennt CWE-1023 automatisch und öffnet in unter 60 Sekunden einen Fix-PR.
Codex Remedium scannt jeden Commit, identifiziert genau diese Schwachstelle und liefert einen reviewer-ready Pull Request mit dem Patch. Keine Tickets. Keine Hand-offs.
Häufig gestellte Fragen Was ist CWE-1023?
Wie gravierend ist CWE-1023?
Welche Sprachen oder Plattformen sind von CWE-1023 betroffen?
Wie kann ich CWE-1023 verhindern?
Wie erkennt und behebt Plexicus CWE-1023?
Wo erfahre ich mehr über CWE-1023?
Frequently asked questions
Was ist CWE-1023?
This weakness occurs when a program compares two items but fails to check all the necessary attributes that define their true relationship. The incomplete check can cause the software to treat different items as identical or make incorrect security decisions.
Wie gravierend ist CWE-1023?
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-1023 betroffen?
MITRE hat für diese CWE keine betroffenen Plattformen spezifiziert — sie kann in den meisten Anwendungs-Stacks auftreten.
Wie kann ich CWE-1023 verhindern?
Thoroughly test the comparison scheme before deploying code into production. Perform positive testing as well as negative testing.
Wie erkennt und behebt Plexicus CWE-1023?
Die SAST-Engine von Plexicus erkennt die Datenfluss-Signatur von CWE-1023 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-1023?
MITRE veröffentlicht die kanonische Definition unter https://cwe.mitre.org/data/definitions/1023.html. Für ergänzende Hinweise kannst du auch die OWASP- und NIST-Dokumentation heranziehen.
Verwandte Schwachstellen
Weaknesses related to CWE-1023
CWE-697 Parent
Incorrect Comparison
This weakness occurs when a security-critical decision relies on a flawed comparison between two pieces of data. The incorrect logic can…
CWE-1024 Sibling
Comparison of Incompatible Types
This vulnerability occurs when code directly compares two values of fundamentally different data types, which can lead to unreliable or…
CWE-1025 Sibling
Comparison Using Wrong Factors
This weakness occurs when a program compares two items but checks the wrong properties or attributes. This flawed comparison leads to…
CWE-1039 Sibling
Inadequate Detection or Handling of Adversarial Input Perturbations in Automated Recognition Mechanism
This vulnerability occurs when a system uses automated AI or machine learning to classify complex inputs like images, audio, or text, but…
CWE-1077 Sibling
Floating Point Comparison with Incorrect Operator
This vulnerability occurs when code compares two floating-point numbers using direct equality operators (like == or !=) without accounting…
CWE-1254 Sibling
Incorrect Comparison Logic Granularity
This vulnerability occurs when a system compares sensitive data, like passwords or authentication tokens, piece-by-piece instead of as a…
CWE-183 Sibling
Permissive List of Allowed Inputs
This vulnerability occurs when an application's security filter uses an allowlist that is too broad, mistakenly permitting dangerous…
CWE-185 Sibling
Incorrect Regular Expression
This vulnerability occurs when a regular expression is written incorrectly, causing it to match or validate data in unintended and…
CWE-581 Sibling
Object Model Violation: Just One of Equals and Hashcode Defined
This vulnerability occurs when a Java class defines either the equals() method or the hashCode() method, but not both, breaking a…
Ressourcen
Further reading
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