CVE-2018-6515 in Puppet Agent
Summary
by MITRE
Puppet Agent 1.10.x prior to 1.10.13, Puppet Agent 5.3.x prior to 5.3.7, and Puppet Agent 5.5.x prior to 5.5.2 on Windows only, with a specially crafted configuration file an attacker could get pxp-agent to load arbitrary code with privilege escalation.
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Analysis
by VulDB Data Team • 02/18/2020
The vulnerability identified as CVE-2018-6515 represents a critical privilege escalation flaw affecting multiple versions of the Puppet Agent software on Windows systems. This issue specifically targets the pxp-agent component which serves as a communication agent within the Puppet infrastructure, facilitating communication between Puppet master servers and managed nodes. The vulnerability arises from insufficient input validation within the configuration file processing mechanism, creating a path for malicious code execution that can elevate privileges from standard user accounts to system-level access.
The technical flaw manifests when the pxp-agent processes specially crafted configuration files that contain malicious code or references to arbitrary executables. This occurs due to inadequate sanitization of input parameters and insufficient validation of file paths within the configuration parsing logic. The vulnerability is particularly dangerous because it allows an attacker to inject code that gets executed with elevated privileges, effectively bypassing normal access controls and system security boundaries. This type of flaw aligns with CWE-22 Path Traversal and CWE-78 Command Injection categories, where improper input handling leads to arbitrary code execution. The vulnerability operates at the system level, making it a prime candidate for exploitation under the MITRE ATT&CK framework's privilege escalation techniques.
The operational impact of CVE-2018-6515 extends beyond simple code execution, as it provides attackers with complete system compromise capabilities. Once an attacker successfully exploits this vulnerability, they gain the ability to install malicious software, modify system configurations, access sensitive data, and maintain persistent access to the compromised system. The vulnerability affects organizations that rely heavily on Puppet for configuration management, as it undermines the security assumptions that normally protect managed nodes from unauthorized access. The impact is particularly severe in enterprise environments where Puppet agents are used to manage critical infrastructure components, potentially allowing attackers to move laterally throughout the network and access additional systems.
Organizations should immediately apply the vendor-provided patches for Puppet Agent versions 1.10.13, 5.3.7, and 5.5.2 to mitigate this vulnerability. Additionally, implementing network segmentation and access controls can help limit the potential impact if exploitation occurs. Security monitoring should focus on unusual file access patterns and privilege escalation events within Puppet-managed environments. The vulnerability demonstrates the importance of input validation in security-critical components and highlights the need for comprehensive security testing of configuration file processing mechanisms. Regular security assessments of infrastructure management tools should include thorough reviews of input validation and privilege handling to prevent similar issues from emerging in other components.