CWE-863 Class Incomplete High likelihood

Incorrect Authorization

This vulnerability occurs when an application checks if a user is allowed to perform an action or access data, but the check is flawed or incomplete, allowing unauthorized access.

Definition

What is CWE-863?

This vulnerability occurs when an application checks if a user is allowed to perform an action or access data, but the check is flawed or incomplete, allowing unauthorized access.
Incorrect authorization happens when the logic that verifies user permissions contains mistakes. For example, the app might check a user's role but forget to verify if they own the specific data they're trying to modify, leading to horizontal privilege escalation. It can also stem from missing checks entirely for certain application paths, or from relying on client-side controls that attackers can easily bypass. These flaws are often subtle and context-dependent, making them hard to catch in code reviews. While SAST tools can identify missing authorization patterns, Plexicus uses AI to analyze the specific business logic and suggest precise code fixes, helping developers close these security gaps efficiently and prevent data breaches.
Vulnerability Diagram CWE-863
Incorrect Authorization user A → /docs/X owner: B authorization check if userRole(A).canEdit ✓ // checks A's perms // not relation to doc → allow wrong subject evaluated A edits B's doc policy bypassed A check exists but evaluates the wrong rule, role or context.
Auswirkungen in der Praxis

Real-world CVEs caused by CWE-863

  • CVE-2025-24839

    collaboration platform allows attacker to access an AI bot by using a plugin to set a critical property

  • CVE-2025-32796

    LLM application development platform allows non-admin users to enable or disable apps using certain API endpoints

  • CVE-2021-39155

    Chain: A microservice integration and management platform compares the hostname in the HTTP Host header in a case-sensitive way (CWE-178, CWE-1289), allowing bypass of the authorization policy (CWE-863) using a hostname with mixed case or other variations.

  • CVE-2019-15900

    Chain: sscanf() call is used to check if a username and group exists, but the return value of sscanf() call is not checked (CWE-252), causing an uninitialized variable to be checked (CWE-457), returning success to allow authorization bypass for executing a privileged (CWE-863).

  • CVE-2009-2213

    Gateway uses default "Allow" configuration for its authorization settings.

  • CVE-2009-0034

    Chain: product does not properly interpret a configuration option for a system group, allowing users to gain privileges.

  • CVE-2008-6123

    Chain: SNMP product does not properly parse a configuration option for which hosts are allowed to connect, allowing unauthorized IP addresses to connect.

  • CVE-2008-7109

    Chain: reliance on client-side security (CWE-602) allows attackers to bypass authorization using a custom client.

Wie Angreifer es ausnutzen

Angreiferpfad Schritt für Schritt

  1. 1

    Identifiziere einen Codepfad, der nicht vertrauenswürdige Eingaben ohne Validierung verarbeitet.

  2. 2

    Erzeuge eine Payload, die das unsichere Verhalten auslöst — Injection, Traversal, Overflow oder Logik-Missbrauch.

  3. 3

    Liefere die Payload über einen normalen Request aus und beobachte die Reaktion der Anwendung.

  4. 4

    Iteriere, bis die Antwort Daten preisgibt, Angreifer-Code ausführt oder Berechtigungen eskaliert.

Verwundbares Codebeispiel

Vulnerable PHP

The following code could be for a medical records application. It displays a record to already authenticated users, confirming the user's authorization using a value stored in a cookie.

Verwundbar PHP 
$role = $_COOKIES['role'];
  if (!$role) {
  	$role = getRole('user');
  	if ($role) {
  		// save the cookie to send out in future responses
  		setcookie("role", $role, time()+60*60*2);
  	}
  	else{
  		ShowLoginScreen();
  		die("\n");
  	}
  }
  if ($role == 'Reader') {
  	DisplayMedicalHistory($_POST['patient_ID']);
  }
  else{
  	die("You are not Authorized to view this record\n");
  }
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-863

  • Architecture and Design Divide the product into anonymous, normal, privileged, and administrative areas. Reduce the attack surface by carefully mapping roles with data and functionality. Use role-based access control (RBAC) [REF-229] to enforce the roles at the appropriate boundaries. Note that this approach may not protect against horizontal authorization, i.e., it will not protect a user from attacking others with the same role.
  • Architecture and Design Ensure that access control checks are performed related to the business logic. These checks may be different than the access control checks that are applied to more generic resources such as files, connections, processes, memory, and database records. For example, a database may restrict access for medical records to a specific database user, but each record might only be intended to be accessible to the patient and the patient's doctor [REF-7].
  • Architecture and Design Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. For example, consider using authorization frameworks such as the JAAS Authorization Framework [REF-233] and the OWASP ESAPI Access Control feature [REF-45].
  • Architecture and Design For web applications, make sure that the access control mechanism is enforced correctly at the server side on every page. Users should not be able to access any unauthorized functionality or information by simply requesting direct access to that page. One way to do this is to ensure that all pages containing sensitive information are not cached, and that all such pages restrict access to requests that are accompanied by an active and authenticated session token associated with a user who has the required permissions to access that page.
  • System Configuration / Installation Use the access control capabilities of your operating system and server environment and define your access control lists accordingly. Use a "default deny" policy when defining these ACLs.
Erkennungssignale

How to detect CWE-863

Automated Static Analysis Limited

Automated static analysis is useful for detecting commonly-used idioms for authorization. A tool may be able to analyze related configuration files, such as .htaccess in Apache web servers, or detect the usage of commonly-used authorization libraries. Generally, automated static analysis tools have difficulty detecting custom authorization schemes. Even if they can be customized to recognize these schemes, they might not be able to tell whether the scheme correctly performs the authorization in a way that cannot be bypassed or subverted by an attacker.

Automated Dynamic Analysis

Automated dynamic analysis may not be able to find interfaces that are protected by authorization checks, even if those checks contain weaknesses.

Manual Analysis Moderate

This weakness can be detected using tools and techniques that require manual (human) analysis, such as penetration testing, threat modeling, and interactive tools that allow the tester to record and modify an active session. Specifically, manual static analysis is useful for evaluating the correctness of custom authorization mechanisms.

Manual Static Analysis - Binary or Bytecode SOAR Partial

According to SOAR [REF-1479], the following detection techniques may be useful: ``` Cost effective for partial coverage: ``` Binary / Bytecode disassembler - then use manual analysis for vulnerabilities & anomalies

Dynamic Analysis with Automated Results Interpretation SOAR Partial

According to SOAR [REF-1479], the following detection techniques may be useful: ``` Cost effective for partial coverage: ``` Web Application Scanner Web Services Scanner Database Scanners

Dynamic Analysis with Manual Results Interpretation SOAR Partial

According to SOAR [REF-1479], the following detection techniques may be useful: ``` Cost effective for partial coverage: ``` Host Application Interface Scanner Fuzz Tester Framework-based Fuzzer Forced Path Execution Monitored Virtual Environment - run potentially malicious code in sandbox / wrapper / virtual machine, see if it does anything suspicious

Plexicus Auto-Fix

Plexicus erkennt CWE-863 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.

Demo anfordern Plexicus kostenlos testen
Häufig gestellte Fragen

Frequently asked questions

Was ist CWE-863?

This vulnerability occurs when an application checks if a user is allowed to perform an action or access data, but the check is flawed or incomplete, allowing unauthorized access.

Wie gravierend ist CWE-863?

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-863 betroffen?

MITRE lists the following affected platforms: Web Server, Database Server.

Wie kann ich CWE-863 verhindern?

Divide the product into anonymous, normal, privileged, and administrative areas. Reduce the attack surface by carefully mapping roles with data and functionality. Use role-based access control (RBAC) [REF-229] to enforce the roles at the appropriate boundaries. Note that this approach may not protect against horizontal authorization, i.e., it will not protect a user from attacking others with the same role. Ensure that access control checks are performed related to the business logic. These…

Wie erkennt und behebt Plexicus CWE-863?

Die SAST-Engine von Plexicus erkennt die Datenfluss-Signatur von CWE-863 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-863?

MITRE veröffentlicht die kanonische Definition unter https://cwe.mitre.org/data/definitions/863.html. Für ergänzende Hinweise kannst du auch die OWASP- und NIST-Dokumentation heranziehen.

Verwandte Schwachstellen

Weaknesses related to CWE-863

CWE-285 Parent

Improper Authorization

This vulnerability occurs when an application fails to properly verify whether a user has permission to access specific data or perform…

CWE-1230 Sibling

Exposure of Sensitive Information Through Metadata

This vulnerability occurs when an application protects the primary source of sensitive data but fails to secure the metadata derived from…

CWE-1256 Sibling

Improper Restriction of Software Interfaces to Hardware Features

This vulnerability occurs when a system's software interfaces to hardware features—like power, clock, or performance management—are not…

CWE-1297 Sibling

Unprotected Confidential Information on Device is Accessible by OSAT Vendors

This vulnerability occurs when a semiconductor chip does not properly secure sensitive data, making it accessible to third-party…

CWE-1328 Sibling

Security Version Number Mutable to Older Versions

This vulnerability occurs when a hardware system's security version number can be changed, allowing an attacker to downgrade or roll back…

CWE-552 Sibling

Files or Directories Accessible to External Parties

This vulnerability occurs when an application exposes files or directories to users who shouldn't have access to them.

CWE-732 Sibling

Incorrect Permission Assignment for Critical Resource

This vulnerability occurs when a system grants overly permissive access to a sensitive resource, allowing unauthorized users or processes…

CWE-862 Sibling

Missing Authorization

This vulnerability occurs when an application fails to verify whether a user has permission to access specific data or execute certain…

CWE-926 Sibling

Improper Export of Android Application Components

This vulnerability occurs when an Android app makes a component (like an Activity, Service, or Content Provider) available to other apps…

Ressourcen

Further reading

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