CVE-2015-5723 in Doctrine Annotation
Summary
by MITRE
Doctrine Annotations before 1.2.7, Cache before 1.3.2 and 1.4.x before 1.4.2, Common before 2.4.3 and 2.5.x before 2.5.1, ORM to before 2.4.8 or 2.5.x before 2.5.1, MongoDB ODM before 1.0.2, and MongoDB ODM Bundle before 3.0.1 use world-writable permissions for cache directories, which allows local users to execute arbitrary PHP code with additional privileges by leveraging an application with the umask set to 0 and that executes cache entries as code.
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Analysis
by VulDB Data Team • 11/22/2024
The vulnerability described in CVE-2015-5723 represents a critical security flaw affecting multiple components of the Doctrine PHP framework ecosystem. This issue specifically targets the cache directory permissions mechanism within Doctrine's various modules including Annotations, Cache, Common, Object Relational Mapping, and MongoDB ODM components. The vulnerability stems from the improper handling of file permissions during cache directory creation, where the system fails to enforce restrictive permission settings that would normally prevent unauthorized code execution.
The technical flaw occurs when applications utilizing Doctrine components are configured with umask set to 0, which effectively removes all permission restrictions during file creation. Under normal circumstances, umask values should prevent newly created files and directories from being world-writable. However, when umask is set to zero, the cache directories created by Doctrine components inherit world-writable permissions, creating a dangerous scenario where local attackers can modify cached files. This vulnerability falls under CWE-732: Incorrect Permission Assignment for Critical Resource, which specifically addresses improper permission settings that allow unauthorized access to system resources.
The operational impact of this vulnerability is severe as it enables local privilege escalation attacks. An attacker with local system access can exploit this weakness by placing malicious PHP code within the world-writable cache directories, which are then executed by the application when the cached content is processed. This creates a persistent backdoor mechanism that can be leveraged to execute arbitrary code with the privileges of the web application user. The attack vector is particularly concerning because it requires minimal prerequisites - simply having local access to a system running a vulnerable Doctrine application with the problematic umask configuration.
The vulnerability affects multiple versions across different Doctrine components, making it widespread across the ecosystem. Specifically, Doctrine Annotations before 1.2.7, Cache before 1.3.2 and 1.4.x before 1.4.2, Common before 2.4.3 and 2.5.x before 2.5.1, ORM before 2.4.8 or 2.5.x before 2.5.1, MongoDB ODM before 1.0.2, and MongoDB ODM Bundle before 3.0.1 are all vulnerable. This demonstrates how the flaw is deeply embedded in the framework's cache handling mechanisms rather than being isolated to a single component.
From an attack perspective, this vulnerability aligns with several tactics described in the MITRE ATT&CK framework, particularly those related to privilege escalation and persistence. The attack pattern follows the technique of "Exploitation for Privilege Escalation" where attackers leverage misconfigured permissions to gain elevated privileges. Additionally, the ability to execute arbitrary code through cached files represents a form of "Command and Script Injection" that can be used to establish persistent access. The vulnerability also relates to "Tactic: Persistence" as attackers can maintain access through modified cache files that continue to execute malicious code.
The recommended mitigation strategies include immediate patching of all affected Doctrine components to versions that properly enforce restrictive permissions on cache directories. Administrators should also review and correct umask settings on affected systems, ensuring that umask values are properly configured to prevent world-writable permissions. Additionally, system administrators should implement monitoring for unusual cache directory modifications and consider implementing more restrictive file system permissions for cache directories. The fix typically involves ensuring that cache directories are created with proper permissions such as 0700 instead of world-writable permissions, which prevents local users from modifying cached content. Organizations should also conduct comprehensive security audits of their Doctrine installations to identify and remediate similar permission issues across their entire application ecosystem.