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.
CWE-863 Class Incomplete
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.
Real-world impact
Real-world CVEs caused by CWE-863
-
collaboration platform allows attacker to access an AI bot by using a plugin to set a critical property
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LLM application development platform allows non-admin users to enable or disable apps using certain API endpoints
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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.
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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).
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Gateway uses default "Allow" configuration for its authorization settings.
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Chain: product does not properly interpret a configuration option for a system group, allowing users to gain privileges.
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Chain: SNMP product does not properly parse a configuration option for which hosts are allowed to connect, allowing unauthorized IP addresses to connect.
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Chain: reliance on client-side security (CWE-602) allows attackers to bypass authorization using a custom client.
How attackers exploit it
Step-by-step attacker path
- 1
Identify a code path that handles untrusted input without validation.
- 2
Craft a payload that exercises the unsafe behavior — injection, traversal, overflow, or logic abuse.
- 3
Deliver the payload through a normal request and observe the application's reaction.
- 4
Iterate until the response leaks data, executes attacker code, or escalates privileges.
Vulnerable code example
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.
$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");
} Secure code example
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.
Prevention checklist
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.
Detection signals
How to detect CWE-863
Automated dynamic analysis may not be able to find interfaces that are protected by authorization checks, even if those checks contain weaknesses.
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.
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
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
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-detects CWE-863 and opens a fix PR in under 60 seconds.
Codex Remedium scans every commit, identifies this exact weakness, and ships a reviewer-ready pull request with the patch. No tickets. No hand-offs.
Frequently asked questions What is CWE-863?
How serious is CWE-863?
What languages or platforms are affected by CWE-863?
How can I prevent CWE-863?
How does Plexicus detect and fix CWE-863?
Where can I learn more about CWE-863?
Frequently asked questions
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.
How serious is CWE-863?
MITRE rates the likelihood of exploit as High — this weakness is actively exploited in the wild and should be prioritized for remediation.
What languages or platforms are affected by CWE-863?
MITRE lists the following affected platforms: Web Server, Database Server.
How can I prevent CWE-863?
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…
How does Plexicus detect and fix CWE-863?
Plexicus's SAST engine matches the data-flow signature for CWE-863 on every commit. When a match is found, our Codex Remedium agent opens a fix PR with the corrected code, tests, and a one-line summary for the reviewer.
Where can I learn more about CWE-863?
MITRE publishes the canonical definition at https://cwe.mitre.org/data/definitions/863.html. You can also reference OWASP and NIST documentation for adjacent guidance.
Related weaknesses
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…
Resources
Further reading
- MITRE — official CWE-863 https://cwe.mitre.org/data/definitions/863.html
- Role Based Access Control and Role Based Security https://csrc.nist.gov/projects/role-based-access-control
- Writing Secure Code https://www.microsoftpressstore.com/store/writing-secure-code-9780735617223
- Top 25 Series - Rank 5 - Improper Access Control (Authorization) https://www.sans.org/blog/top-25-series-rank-5-improper-access-control-authorization
- Authentication using JAAS https://javaranch.com/journal/2008/04/authentication-using-JAAS.html
- OWASP Enterprise Security API (ESAPI) Project https://owasp.org/www-project-enterprise-security-api/
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