CVE-2013-2027 in WebLogic Server
Summary
by MITRE
Jython 2.2.1 uses the current umask to set the privileges of the class cache files, which allows local users to bypass intended access restrictions via unspecified vectors.
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Analysis
by VulDB Data Team • 10/29/2019
The vulnerability identified as CVE-2013-2027 affects Jython version 2.2.1 and represents a significant security flaw in how the system handles file permissions for class cache files. This issue stems from Jython's improper use of the current umask value when creating cache files, which can lead to unauthorized access to compiled class files that should remain restricted. The vulnerability exists within the Java-based Python implementation known as Jython, which is particularly concerning given its widespread use in enterprise environments and web applications where security controls are paramount. The flaw allows local attackers to manipulate file permissions and potentially gain access to sensitive compiled code that could be exploited for privilege escalation or information disclosure attacks.
The technical root cause of this vulnerability lies in Jython's class cache mechanism that stores compiled bytecode representations of Python classes for performance optimization. When Jython creates these cache files, it incorrectly relies on the system's current umask setting rather than establishing appropriate restrictive permissions. This behavior violates fundamental security principles and creates opportunities for attackers to exploit the system's permission model. The umask value, which typically controls default file permissions for newly created files, when improperly applied to cache files, can result in files being created with overly permissive access controls that expose them to unauthorized users. This flaw operates at the file system level and demonstrates poor security implementation practices in the application's file handling routines.
The operational impact of CVE-2013-2027 extends beyond simple permission issues and can enable local privilege escalation attacks, information disclosure, and potentially more severe exploitation scenarios. Attackers could leverage this vulnerability to access cached class files that might contain sensitive application logic, configuration details, or other proprietary information that should remain protected. The vulnerability is particularly dangerous in multi-user environments where different users share the same system resources, as it could allow one user to access another user's compiled class files. This could lead to reverse engineering of application logic, exposure of business-critical information, or even facilitate further attacks on the system. The unspecified vectors mentioned in the description suggest that multiple attack paths could exist, making this vulnerability particularly concerning from a threat modeling perspective.
Security professionals should consider this vulnerability in relation to CWE-732, which addresses incorrect permission assignment, and potentially CWE-276, which covers incorrect file permissions. The vulnerability also aligns with ATT&CK techniques related to privilege escalation and credential access, as it provides a pathway for local users to bypass intended access controls. Organizations should implement immediate mitigations including updating to a patched version of Jython, manually setting restrictive umask values for Jython processes, and conducting thorough audits of existing cache files to identify any potentially compromised permissions. Additionally, system administrators should monitor for unauthorized access to cache directories and implement proper file system access controls to prevent exploitation of this vulnerability. The remediation approach should also include reviewing other applications that might be similarly affected by improper umask usage in their file creation processes.