CVE-2015-7328 in Puppet
Summary
by MITRE
Puppet Server in Puppet Enterprise before 3.8.x before 3.8.3 and 2015.2.x before 2015.2.3 uses world-readable permissions for the private key of the Certification Authority (CA) certificate during the initial installation and configuration, which might allow local users to obtain sensitive information via unspecified vectors.
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Analysis
by VulDB Data Team • 06/06/2018
The vulnerability identified as CVE-2015-7328 affects Puppet Enterprise server installations where the Certification Authority private key file is created with overly permissive world-readable permissions during the initial setup process. This flaw exists in versions prior to 3.8.3 for the 3.8.x series and 2015.2.3 for the 2015.2.x series, representing a critical security oversight in the certificate management infrastructure of the Puppet configuration management platform. The issue stems from improper file permission handling during the certificate authority initialization, which creates a persistent security weakness that can be exploited by local attackers with minimal privileges.
The technical flaw manifests when Puppet Server generates the CA certificate private key during installation, storing it with permissions that allow any local user on the system to read the sensitive cryptographic material. This represents a violation of the principle of least privilege and directly contravenes security best practices for handling private keys. The world-readable permissions create an attack surface where local users can extract the CA private key through standard file system access mechanisms, potentially enabling them to impersonate the certificate authority and issue fraudulent certificates for the Puppet infrastructure. This vulnerability aligns with CWE-732, which describes improper permission assignment for critical resources, and specifically demonstrates how inadequate file system permissions can lead to privilege escalation and credential compromise.
The operational impact of this vulnerability is significant for organizations relying on Puppet Enterprise for configuration management, as it provides local attackers with the means to completely compromise the certificate-based security model that Puppet depends upon. An attacker with local access could use the extracted CA private key to generate valid certificates for any Puppet client or server, effectively breaking the entire trust relationship within the Puppet infrastructure. This enables man-in-the-middle attacks against Puppet communications, allows for unauthorized configuration changes, and potentially provides access to sensitive data processed through the Puppet system. The vulnerability also aligns with ATT&CK technique T1552.001, which covers "Unsecured Credentials" and specifically addresses the exposure of private keys through improper file permissions.
Organizations should immediately implement mitigations including updating to the patched versions of Puppet Enterprise 3.8.3 or 2015.2.3, verifying file permissions on existing CA private key files, and implementing proper access controls on certificate management directories. System administrators should conduct thorough audits of all Puppet-related certificate files and ensure that private keys are stored with restrictive permissions such as 600 or 640, preventing unauthorized access while maintaining necessary operational functionality. Additionally, organizations should review their overall certificate management practices and consider implementing automated monitoring for unauthorized changes to critical certificate files, as this vulnerability demonstrates how seemingly minor configuration oversights can create substantial security risks in enterprise infrastructure management systems.