CVE-2016-5713 in Puppet
Summary
by MITRE
Versions of Puppet Agent prior to 1.6.0 included a version of the Puppet Execution Protocol (PXP) agent that passed environment variables through to Puppet runs. This could allow unauthorized code to be loaded. This bug was first introduced in Puppet Agent 1.3.0.
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Analysis
by VulDB Data Team • 12/12/2019
The vulnerability identified as CVE-2016-5713 represents a critical security flaw in Puppet Agent versions prior to 1.6.0, specifically within the Puppet Execution Protocol (PXP) agent implementation. This issue stems from the improper handling of environment variables during Puppet execution processes, creating a potential vector for unauthorized code loading and execution. The vulnerability was introduced in version 1.3.0 and remained unpatched until the release of 1.6.0, exposing numerous systems to significant security risks.
The technical flaw manifests through the PXP agent's insecure transmission of environment variables to Puppet runs, which creates an attack surface where malicious actors can manipulate system variables to inject and execute unauthorized code. This behavior directly violates secure coding principles and represents a classic example of environment variable injection vulnerabilities. The flaw allows attackers to leverage existing Puppet infrastructure to execute arbitrary code with the privileges of the Puppet agent process, potentially leading to full system compromise.
From an operational perspective, this vulnerability poses severe risks to organizations relying on Puppet for configuration management. Attackers exploiting this weakness could gain persistent access to managed systems, escalate privileges, and potentially move laterally within networks. The impact extends beyond individual system compromise to affect entire infrastructure configurations, as Puppet agents typically run with elevated privileges to perform system changes. This vulnerability particularly affects environments where Puppet is used for automated deployment and configuration management across multiple servers and workloads.
The security implications align with CWE-254, which addresses 'Security Features' vulnerabilities related to improper handling of environment variables and process execution. Additionally, this vulnerability maps to ATT&CK technique T1059.001 for command and scripting interpreter, as attackers could leverage the compromised Puppet agent to execute arbitrary commands. Organizations should implement immediate mitigations including upgrading to Puppet Agent 1.6.0 or later, reviewing and restricting environment variable passing mechanisms, and monitoring for unauthorized Puppet execution patterns. The vulnerability also highlights the importance of proper input validation and secure process spawning practices in configuration management tools, emphasizing the need for robust security testing throughout the software development lifecycle to prevent such issues from reaching production environments.