CVE-2015-3908 in Ansible
Summary
by MITRE
Ansible before 1.9.2 does not verify that the server hostname matches a domain name in the subject's Common Name (CN) or subjectAltName field of the X.509 certificate, which allows man-in-the-middle attackers to spoof SSL servers via an arbitrary valid certificate.
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Analysis
by VulDB Data Team • 11/24/2024
The vulnerability identified as CVE-2015-3908 affects Ansible versions prior to 1.9.2 and represents a critical SSL/TLS security flaw that undermines the integrity of secure communications. This issue stems from insufficient certificate validation mechanisms within the Ansible automation platform, specifically in how it handles SSL certificate verification during remote server connections. The vulnerability allows attackers to perform man-in-the-middle attacks by presenting arbitrary valid SSL certificates that do not properly match the expected server hostname, effectively breaking the trust model that SSL/TLS is designed to establish.
The technical flaw manifests in the certificate validation process where Ansible fails to properly validate the hostname against the X.509 certificate's Common Name field or subjectAltName extension. According to the x509 standard and security best practices, when establishing SSL connections, clients must verify that the certificate presented by the server matches the hostname being connected to. This validation ensures that the client is communicating with the intended server and not an attacker impersonating that server. In the case of CVE-2015-3908, Ansible's implementation bypasses this crucial step, allowing attackers to present any valid certificate regardless of whether it corresponds to the target server's domain name.
The operational impact of this vulnerability is severe as it enables attackers to intercept and potentially manipulate all Ansible communications that rely on SSL/TLS encryption. When Ansible connects to managed nodes or remote servers, an attacker positioned in the network can present a fake SSL certificate signed by a legitimate Certificate Authority, thereby deceiving the Ansible control node into believing it's communicating with a legitimate target. This vulnerability affects Ansible's ability to maintain secure connections to remote systems, potentially allowing attackers to execute arbitrary commands on target systems, access sensitive configuration data, or redirect communications to malicious endpoints. The flaw particularly impacts automated security operations and infrastructure management processes that depend on Ansible's secure communication channels.
This vulnerability aligns with CWE-295, which specifically addresses improper certificate validation, and relates to ATT&CK technique T1071.004 for Application Layer Protocol: DNS, where attackers may leverage weakened certificate validation to establish unauthorized communication channels. The security implications extend beyond simple credential theft to encompass complete system compromise when Ansible is used for privileged operations. Organizations utilizing Ansible for configuration management, deployment automation, or security orchestration face significant risk exposure, particularly in environments where network traffic is not properly segmented or monitored. The vulnerability's impact is amplified in cloud environments and containerized deployments where Ansible is commonly used for infrastructure provisioning and management tasks.
The recommended mitigation strategy involves upgrading Ansible to version 1.9.2 or later, which includes proper hostname verification mechanisms. Organizations should also implement additional security controls such as certificate pinning for critical systems, network monitoring to detect unusual SSL certificate behavior, and regular security assessments of automation toolchains. System administrators should review and test their Ansible configurations to ensure that certificate validation is properly enforced, and consider implementing additional layers of authentication such as SSH key-based authentication alongside SSL/TLS to provide defense in depth. Furthermore, organizations should conduct comprehensive security audits of their automation infrastructure to identify and remediate similar certificate validation issues in other tools and services that may be part of their operational environment.