CVE-2016-8628 in Ansible
Summary
by MITRE
Ansible before version 2.2.0 fails to properly sanitize fact variables sent from the Ansible controller. An attacker with the ability to create special variables on the controller could execute arbitrary commands on Ansible clients as the user Ansible runs as.
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Analysis
by VulDB Data Team • 04/27/2023
The vulnerability identified as CVE-2016-8628 represents a critical command injection flaw within Ansible automation software prior to version 2.2.0. This issue stems from insufficient sanitization of fact variables transmitted from the Ansible controller to managed nodes, creating a pathway for remote code execution. The flaw exists in the way Ansible processes and handles variables that are passed between the controller and client systems, particularly when these variables contain maliciously crafted content that bypasses normal input validation mechanisms.
The technical implementation of this vulnerability involves the improper handling of variable interpolation and execution contexts within Ansible's fact processing pipeline. When Ansible controllers send fact variables to client systems, the software does not adequately sanitize these inputs before they are processed or executed within the client environment. This weakness allows attackers who can influence variable creation on the controller side to inject malicious commands that get executed on the target systems. The vulnerability specifically impacts the execution context where Ansible processes these variables, potentially allowing arbitrary code execution with the privileges of the Ansible user account.
Operationally, this vulnerability presents a severe risk to organizations relying on Ansible for automation and configuration management. Attackers who can manipulate variables on the controller system can escalate their privileges to execute commands on managed nodes without requiring direct access to those systems. The impact extends beyond simple command execution as it can enable attackers to establish persistent access, escalate privileges, or move laterally within network environments. The vulnerability affects the core security model of Ansible's architecture, where trust is placed in controller-to-client communication, making it particularly dangerous in enterprise environments where Ansible is used extensively for infrastructure automation.
The security implications of CVE-2016-8628 align with CWE-74 and CWE-94 categories, which address injection flaws and code injection vulnerabilities respectively. This vulnerability also maps to ATT&CK techniques such as T1059 for command and scripting interpreter and T1105 for remote file execution. Organizations should implement immediate mitigation strategies including upgrading to Ansible version 2.2.0 or later, implementing strict variable validation policies, and conducting comprehensive security reviews of existing Ansible playbooks and variable management practices. Additional protective measures include network segmentation, monitoring for unusual command execution patterns, and implementing principle of least privilege for Ansible user accounts to limit potential damage from successful exploitation attempts.