CVE-2019-10156 in Ansible
Summary
by MITRE
A flaw was discovered in the way Ansible templating was implemented in versions before 2.6.18, 2.7.12 and 2.8.2, causing the possibility of information disclosure through unexpected variable substitution. By taking advantage of unintended variable substitution the content of any variable may be disclosed.
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Analysis
by VulDB Data Team • 11/14/2023
The vulnerability identified as CVE-2019-10156 represents a critical information disclosure flaw within Ansible's templating engine that affected multiple versions prior to 2.6.18, 2.7.12, and 2.8.2. This issue stems from improper handling of variable substitution mechanisms within Ansible's template processing system, creating unexpected pathways for unauthorized data exposure. The flaw specifically impacts how Ansible interprets and processes template variables, allowing attackers to exploit unintended substitution behaviors to access sensitive information stored in variables. This vulnerability directly undermines the security assurances that Ansible's templating system should provide to users managing infrastructure automation.
The technical implementation of this vulnerability resides in Ansible's template parsing logic where variable substitution occurs during template rendering. When Ansible processes templates containing variables, the system fails to properly validate or sanitize variable names and references, enabling attackers to craft malicious templates that trigger unintended variable resolution. This flaw operates through a combination of variable name collision and improper scope handling within Ansible's templating engine, allowing attackers to access variables that should remain isolated or protected. The vulnerability can be exploited by crafting template files that contain specially formatted variable references designed to trigger the unintended substitution behavior, potentially exposing sensitive data such as passwords, API keys, or configuration details stored in Ansible variables.
The operational impact of CVE-2019-10156 extends beyond simple information disclosure to represent a significant threat to infrastructure security automation environments. Organizations relying on Ansible for configuration management, deployment automation, or orchestration tasks face potential exposure of critical credentials and sensitive configuration data. Attackers exploiting this vulnerability could gain access to variables containing database credentials, cloud service tokens, SSH keys, or other privileged information stored within Ansible inventory files, group variables, or host variables. This exposure creates a vector for privilege escalation and lateral movement within automated environments, as the compromised information could enable attackers to access additional systems or resources that depend on the disclosed credentials. The vulnerability's impact is particularly severe in environments where Ansible templates are processed with elevated privileges or where sensitive data is stored in variables accessible to automated processes.
Mitigation strategies for CVE-2019-10156 require immediate version upgrades to patched releases of Ansible, specifically versions 2.6.18, 2.7.12, or 2.8.2, which contain the necessary fixes to address the variable substitution vulnerability. Organizations should also implement comprehensive template review processes to identify and remediate any potentially vulnerable templates in their automation workflows before upgrading. Security teams should conduct thorough inventory assessments to identify all systems running affected Ansible versions and prioritize patching activities based on risk exposure. Additionally, implementing proper template validation controls and restricting template execution privileges can provide additional defense-in-depth measures. This vulnerability aligns with CWE-20: Improper Input Validation and ATT&CK technique T1552.001: Unsecured Credentials, highlighting the need for proper input sanitization and credential protection mechanisms in automation frameworks. Organizations should also consider implementing monitoring for unusual template processing patterns that might indicate exploitation attempts.