CVE-2005-2656 in Polygen
Summary
by MITRE
Polygen before 1.0.6 generates precompiled grammar objects with world-writable permissions, which allows local users to cause a denial of service (disk consumption) and possibly perform other unauthorized activities.
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Analysis
by VulDB Data Team • 06/09/2019
The vulnerability described in CVE-2005-2656 affects Polygen versions prior to 1.0.6, a tool used for generating code from grammar specifications. This issue represents a classic permissions misconfiguration that undermines system security through improper file access controls. The flaw manifests when the application creates precompiled grammar objects with world-writable permissions, meaning any local user can modify or delete these files. This vulnerability falls under the category of improper file permissions as classified by CWE-732, which specifically addresses inadequate permissions for critical resources. The security implications extend beyond simple access control issues as they create opportunities for privilege escalation and system compromise through manipulation of critical application components.
The technical mechanism behind this vulnerability involves the application's failure to properly set file permissions during the creation of precompiled grammar objects. When Polygen generates these objects, it creates files with permissions that allow any user on the system to write to them, effectively creating a race condition and potential attack vector. This misconfiguration enables local users to modify or replace these grammar files with malicious content, potentially leading to code injection or execution of arbitrary commands. The vulnerability specifically targets the file system permissions model, where the default umask settings or explicit permission assignments fail to restrict write access to authorized users only, creating a persistent security weakness in the application's deployment.
The operational impact of this vulnerability is significant as it provides local users with the capability to consume excessive disk space through denial of service attacks, effectively rendering the system unusable for legitimate operations. Attackers can exploit this weakness to continuously overwrite or append to the precompiled grammar objects, causing disk exhaustion and system instability. Additionally, the world-writable permissions create opportunities for more sophisticated attacks where malicious users can inject harmful code into the grammar objects, potentially leading to privilege escalation or unauthorized system access. This vulnerability is particularly dangerous in multi-user environments where different users share the same system resources and can leverage the misconfigured permissions to compromise system integrity.
Mitigation strategies for this vulnerability require immediate attention to file system permissions and application security practices. System administrators should ensure that Polygen is updated to version 1.0.6 or later, which addresses the improper permission handling issue. Additionally, implementing proper umask settings and explicit permission controls during file creation can prevent similar issues in other applications. Security hardening measures should include regular permission audits and privilege reviews to identify and correct similar misconfigurations. The remediation process should also involve monitoring system logs for unauthorized file modifications and implementing automated alerts for suspicious permission changes. This vulnerability demonstrates the critical importance of proper access control implementation and aligns with ATT&CK technique T1068, which covers privilege escalation through local exploits. Organizations should also consider implementing least privilege principles and regular security assessments to identify and remediate similar permission-related vulnerabilities across their software infrastructure.