CVE-2012-6432 in Symfony
Summary
by MITRE
Symfony 2.0.x before 2.0.20, 2.1.x before 2.1.5, and 2.2-dev, when the internal routes configuration is enabled, allows remote attackers to access arbitrary services via vectors involving a URI beginning with a /_internal substring.
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Analysis
by VulDB Data Team • 12/21/2021
The vulnerability identified as CVE-2012-6432 affects Symfony web applications running version 2.0.x before 2.0.20, 2.1.x before 2.1.5, and 2.2-dev releases. This security flaw resides in the routing component of the Symfony framework and specifically impacts applications that have internal routes configuration enabled. The vulnerability stems from insufficient input validation and access control mechanisms within the routing system, creating a path for unauthorized remote access to sensitive application services.
The technical implementation of this vulnerability involves a flaw in how Symfony processes URIs that begin with the /_internal substring. When internal routes are enabled, the framework should restrict access to these routes to prevent unauthorized users from invoking internal service endpoints. However, the vulnerability allows remote attackers to craft malicious requests that bypass these access controls by leveraging the specific URI pattern that starts with /_internal. This design flaw enables attackers to access services that should remain protected within the application's internal architecture.
The operational impact of this vulnerability is significant as it provides remote attackers with the ability to access arbitrary services within the application's internal routing system. Attackers can potentially exploit this to gain unauthorized access to internal application components, retrieve sensitive information, or even execute arbitrary code depending on the exposed services. The vulnerability essentially creates a backdoor access point that bypasses normal authentication and authorization mechanisms, potentially leading to complete application compromise. This type of vulnerability aligns with CWE-284, which describes improper access control issues, and represents a classic case of insufficient authorization checking in web applications.
The security implications extend beyond simple information disclosure as attackers can leverage this vulnerability to escalate privileges and access services that should only be available to administrators or internal system components. This vulnerability particularly affects web applications that utilize Symfony's internal routing features for debugging, monitoring, or administrative purposes. The attack vector is straightforward and can be executed remotely without requiring any special privileges or authentication credentials, making it particularly dangerous in production environments where such internal services may expose sensitive backend functionality.
Organizations affected by this vulnerability should immediately implement the available patches from Symfony's official releases, specifically upgrading to versions 2.0.20, 2.1.5, or later. Additionally, administrators should consider implementing network-level restrictions to prevent external access to internal routes, though this approach provides only partial protection. The recommended mitigation strategy involves disabling internal routes in production environments when they are not specifically required for debugging purposes, aligning with the principle of least privilege and defense in depth. Security teams should also monitor application logs for suspicious access patterns and implement proper network segmentation to limit potential attack surface. This vulnerability demonstrates the critical importance of proper input validation and access control implementation in web frameworks, as highlighted by ATT&CK technique T1212 which addresses exploitation of software vulnerabilities for privilege escalation and information access.