CVE-2016-9587 in Ansible
Summary
by MITRE
Ansible before versions 2.1.4, 2.2.1 is vulnerable to an improper input validation in Ansible's handling of data sent from client systems. An attacker with control over a client system being managed by Ansible and the ability to send facts back to the Ansible server could use this flaw to execute arbitrary code on the Ansible server using the Ansible server privileges.
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Analysis
by VulDB Data Team • 11/30/2024
The vulnerability identified as CVE-2016-9587 represents a critical security flaw in Ansible automation software that affects versions prior to 2.1.4 and 2.2.1. This issue stems from inadequate input validation mechanisms within Ansible's fact handling system, creating a pathway for remote code execution attacks. The vulnerability specifically targets the communication channel between managed client systems and the central Ansible server, where client systems can send system facts back to the server for processing and inventory management purposes.
The technical flaw manifests in Ansible's improper validation of data received from client systems during the fact collection process. When managed nodes transmit system information back to the Ansible server, the software fails to adequately sanitize or validate the incoming data structures. This validation gap allows an attacker who has compromised or gained control over a client system to craft malicious fact data that, when processed by the Ansible server, triggers arbitrary code execution. The vulnerability is particularly dangerous because it leverages the legitimate communication channels that Ansible uses for system management, making it difficult to detect and distinguish from normal operational traffic.
The operational impact of this vulnerability is severe and far-reaching within automated infrastructure environments. An attacker who successfully exploits this flaw can execute commands on the Ansible server with the same privileges as the Ansible service account, potentially gaining access to sensitive configuration data, credentials, and system resources. This compromise can lead to lateral movement throughout the network, as Ansible servers often have elevated privileges and access to multiple managed systems. The attack vector requires only that the attacker control a single managed client system, making it particularly effective in environments where numerous systems are managed through a central Ansible server.
From a cybersecurity perspective, this vulnerability maps to CWE-20, which describes improper input validation, and aligns with ATT&CK technique T1059.001 for command and script injection. The flaw demonstrates how automation tools can become attack vectors when proper security controls are not implemented in data handling processes. Organizations using Ansible for infrastructure automation face significant risk if they operate vulnerable versions, as the compromise of any managed node could potentially lead to full control of the central automation server. The vulnerability underscores the importance of validating all data received from external sources, even in trusted automation environments where data integrity is assumed.
Mitigation strategies for CVE-2016-9587 require immediate patching of Ansible installations to versions 2.1.4 or 2.2.1, which contain the necessary input validation fixes. Organizations should also implement network segmentation to isolate Ansible servers from less secure network segments and establish strict access controls for client systems. Additional defensive measures include monitoring for unusual fact data patterns, implementing network intrusion detection systems, and ensuring that Ansible servers run with minimal required privileges. Regular security assessments of automation infrastructure are essential to identify and remediate similar vulnerabilities in other tools and systems within the organization's infrastructure.