CVE-2011-4328 in Gnash
Summary
by MITRE
plugin/npapi/plugin.cpp in Gnash before 0.8.10 uses weak permissions (world readable) for cookie files with predictable names in /tmp, which allows local users to obtain sensitive information.
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Analysis
by VulDB Data Team • 12/04/2021
The vulnerability identified as CVE-2011-4328 resides within the Gnash multimedia plugin software, specifically in the npapi plugin implementation located at plugin/npapi/plugin.cpp. This issue affects versions prior to 0.8.10 and represents a significant security flaw that compromises the confidentiality of user data through improper file permission handling. The vulnerability manifests when the plugin creates cookie files with predictable naming conventions in the /tmp directory, a common temporary storage location on unix-like systems that is accessible to all users on the system.
The technical flaw stems from the implementation's failure to properly secure temporary cookie files by setting appropriate file permissions. When Gnash generates these cookie files, it assigns them world-readable permissions, meaning any local user on the system can access these files. The predictable naming scheme combined with the weak permissions creates a straightforward attack vector where malicious users can enumerate and read the contents of these temporary files to extract sensitive information that would normally be protected. This represents a violation of the principle of least privilege and demonstrates poor security practices in temporary file management.
The operational impact of this vulnerability extends beyond simple information disclosure, as the cookie files may contain session identifiers, authentication tokens, or other sensitive data that could be leveraged by attackers to impersonate users or gain unauthorized access to systems. The local nature of the attack means that an attacker does not require network access or remote exploitation capabilities, making this vulnerability particularly concerning for environments where multiple users share the same system. The predictable file naming convention eliminates the need for extensive reconnaissance, as attackers can simply target known locations and file patterns to access the sensitive information.
This vulnerability aligns with CWE-732, which focuses on Incorrect Permission Assignment for Critical Resources, and represents a clear violation of secure coding practices. From an attack perspective, this flaw can be categorized under the ATT&CK technique T1083 (File and Directory Discovery) and potentially T1566 (Phishing) if the stolen cookie data leads to session hijacking or credential compromise. The issue demonstrates the importance of proper temporary file handling and secure permission management, as outlined in various security frameworks including the OWASP Secure Coding Practices. Organizations using Gnash or similar multimedia plugins should prioritize immediate patching to address this vulnerability and implement monitoring for any suspicious access patterns to temporary directories.
The remediation approach involves updating to Gnash version 0.8.10 or later, where the software properly implements secure file permissions for temporary cookie files. Additionally, system administrators should conduct security audits to identify any other applications that may be creating files with weak permissions in temporary directories. The fix typically involves setting appropriate file permissions that restrict access to the creating process only, often using chmod operations with restrictive permission masks such as 0600 or 0640, depending on the specific requirements of the application's operation. Regular security scanning of temporary directories and implementation of proper file access controls should be part of ongoing system maintenance to prevent similar vulnerabilities from emerging in other software components.