CVE-2018-16876 in Ansible
Summary
by MITRE
ansible before versions 2.5.14, 2.6.11, 2.7.5 is vulnerable to a information disclosure flaw in vvv+ mode with no_log on that can lead to leakage of sensible data.
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Analysis
by VulDB Data Team • 06/22/2023
The vulnerability identified as CVE-2018-16876 affects Ansible versions prior to 2.5.14, 2.6.11, and 2.7.5, representing a critical information disclosure flaw that undermines the security controls designed to protect sensitive data during automated infrastructure provisioning. This vulnerability specifically manifests in the vvv+ mode of Ansible's execution environment, where the no_log parameter fails to adequately prevent exposure of confidential information. The flaw stems from improper handling of logging mechanisms within Ansible's execution framework, allowing attackers to potentially access data that should remain protected through the no_log directive.
The technical implementation of this vulnerability involves a weakness in Ansible's logging subsystem where sensitive information processed through tasks configured with no_log parameter is still visible in verbose output modes. When Ansible operates in vvv+ mode, which provides extremely verbose output for debugging purposes, the system fails to properly sanitize or suppress sensitive data that should be masked according to the no_log directive. This creates an information disclosure scenario where credentials, API keys, passwords, and other confidential data can be exposed in log files or console output, undermining the security assurances that administrators expect from Ansible's configuration management capabilities.
From an operational impact perspective, this vulnerability presents significant risk to organizations relying on Ansible for infrastructure automation, particularly in environments where sensitive data handling is critical. The exposure of sensitive information through verbose logging can lead to unauthorized access to production systems, compromise of authentication credentials, and potential data breaches that could affect compliance with security standards such as pci dss, hipaa, and soc 2. The vulnerability is particularly concerning because it operates at the execution layer of Ansible, meaning that even when administrators implement proper security controls through no_log directives, those protections can be bypassed through the verbose logging mechanism.
The vulnerability aligns with CWE-200, which addresses "Information Exposure," and represents a failure to properly implement information hiding mechanisms within the application. From an ATT&CK framework perspective, this vulnerability maps to techniques involving credential access and defense evasion, as attackers could leverage the exposed information to gain unauthorized access to systems while potentially avoiding detection through compromised credentials. Organizations using Ansible in production environments should consider this vulnerability as part of their broader security posture assessment, particularly when implementing security controls around privileged information handling and access management.
Mitigation strategies for CVE-2018-16876 require immediate patching of affected Ansible installations to versions 2.5.14, 2.6.11, or 2.7.5, which contain the necessary fixes to properly enforce no_log directives even in verbose execution modes. Organizations should also implement additional monitoring of verbose logging output, review existing playbooks for proper no_log implementation, and consider implementing centralized logging controls that can filter out sensitive information regardless of logging verbosity. Security teams should conduct comprehensive audits of Ansible configurations to ensure that no_log directives are properly applied across all sensitive data handling operations and that verbose logging modes are appropriately restricted in production environments to prevent accidental exposure of confidential information.