CVE-2012-3866 in Puppet
Summary
by MITRE
lib/puppet/defaults.rb in Puppet 2.7.x before 2.7.18, and Puppet Enterprise before 2.5.2, uses 0644 permissions for last_run_report.yaml, which allows local users to obtain sensitive configuration information by leveraging access to the puppet master server to read this file.
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Analysis
by VulDB Data Team • 12/07/2021
The vulnerability described in CVE-2012-3866 represents a critical privilege escalation and information disclosure issue within the Puppet configuration management system. This flaw exists in the default file permissions handling mechanism within Puppet's core libraries, specifically affecting versions prior to 2.7.18 of the standard Puppet distribution and before 2.5.2 of Puppet Enterprise. The vulnerability stems from the improper handling of file permissions for the last_run_report.yaml file, which contains sensitive configuration data that should remain protected from unauthorized access.
The technical implementation of this vulnerability occurs in the lib/puppet/defaults.rb file where Puppet sets default permissions to 0644 for the last_run_report.yaml file. This permission setting allows read access to all users on the system while maintaining write permissions only for the owner. The flaw becomes exploitable when local users who have access to the puppet master server can leverage their existing privileges to read this file, thereby gaining access to sensitive configuration information that would normally be restricted. This represents a clear violation of the principle of least privilege and demonstrates a failure in proper access control implementation.
The operational impact of this vulnerability extends beyond simple information disclosure, as it provides attackers with detailed insights into the target system's configuration, including installed packages, file permissions, and other sensitive system attributes. This information can be used for further exploitation attempts, such as identifying system weaknesses, planning targeted attacks, or mapping the attack surface for more sophisticated breaches. The vulnerability is particularly dangerous in enterprise environments where Puppet is used for configuration management, as it could expose the entire infrastructure configuration to unauthorized parties. This aligns with CWE-276, which addresses improper file permissions, and represents a classic case of insufficient access control mechanisms.
The security implications of this vulnerability can be analyzed through the ATT&CK framework, where it maps to techniques involving privilege escalation and credential access. Attackers who gain access to the puppet master server can utilize this flaw to extract sensitive information without requiring additional authentication mechanisms. The vulnerability also demonstrates poor security hygiene in the software development lifecycle, as proper file permission handling should have been implemented during the initial design phase. Organizations using Puppet in production environments should immediately implement patch management procedures to address this vulnerability, as it represents a significant risk to system security and compliance requirements. The remediation involves updating to the patched versions of Puppet and Puppet Enterprise, while also reviewing and implementing proper file permission controls across all configuration management systems to prevent similar issues from occurring in the future.