CVE-2015-9236 in Hapi
Summary
by MITRE
Hapi versions less than 11.0.0 implement CORS incorrectly and allowed for configurations that at best returned inconsistent headers and at worst allowed cross-origin activities that were expected to be forbidden. If the connection has CORS enabled but one route has it off, and the route is not GET, the OPTIONS prefetch request will return the default CORS headers and then the actual request will go through and return no CORS headers. This defeats the purpose of turning CORS on the route.
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 03/17/2023
The vulnerability identified as CVE-2015-9236 affects Hapi.js web framework versions prior to 11.0.0 and represents a critical cross-origin resource sharing implementation flaw that undermines web application security. This issue stems from an inconsistent CORS configuration handling mechanism within the framework's routing system where the framework fails to properly enforce CORS policies across all HTTP methods and routes. The vulnerability specifically manifests when a server connection has CORS enabled globally but individual routes have CORS disabled, creating a dangerous inconsistency in header responses that can be exploited by malicious actors to bypass intended security restrictions.
The technical flaw occurs due to improper handling of preflight OPTIONS requests in the CORS implementation. When a route with CORS disabled receives a non-GET request, the framework responds to the OPTIONS preflight request with default CORS headers while allowing the actual request to proceed without any CORS headers. This creates a scenario where the initial preflight check appears to authorize cross-origin access, but the subsequent actual request fails to provide proper CORS headers, leading to inconsistent security behavior. The vulnerability is particularly dangerous because it allows attackers to perform cross-origin operations that should have been forbidden, effectively creating a bypass mechanism for CORS restrictions that are meant to prevent unauthorized cross-domain requests.
From an operational impact perspective, this vulnerability enables attackers to perform cross-origin resource sharing activities that should be restricted, potentially allowing unauthorized access to sensitive resources and data. The inconsistent header responses can confuse client-side applications and security tools that rely on proper CORS header implementation for their security decisions. This flaw can be exploited to perform unauthorized cross-domain requests that would normally be blocked by CORS policies, potentially leading to data leakage, privilege escalation, or other security breaches. The vulnerability is particularly concerning in environments where multiple routes have varying CORS configurations, as it creates unpredictable security boundaries.
Security mitigations for CVE-2015-9236 require immediate upgrading to Hapi.js version 11.0.0 or later where the CORS implementation has been properly corrected. Organizations should conduct comprehensive audits of their CORS configurations to ensure consistent policy enforcement across all routes and HTTP methods. The fix addresses the root cause by ensuring that CORS headers are consistently applied regardless of individual route configurations, preventing the inconsistent behavior that enabled the exploitation. This vulnerability aligns with CWE-346, which covers "Origin Validation Error" and relates to improper validation of the origin header in web applications. The attack pattern follows ATT&CK technique T1190, which involves exploiting vulnerabilities in web applications to bypass security controls, specifically targeting the CORS mechanism as a means to perform unauthorized cross-origin activities. Organizations should also implement proper security monitoring to detect anomalous CORS header responses that might indicate exploitation attempts.