CVE-2020-1736 in Ansible Engine
Summary
by MITRE
A flaw was found in Ansible Engine when a file is moved using atomic_move primitive as the file mode cannot be specified. This sets the destination files world-readable if the destination file does not exist and if the file exists, the file could be changed to have less restrictive permissions before the move. This could lead to the disclosure of sensitive data. All versions in 2.7.x, 2.8.x and 2.9.x branches are believed to be vulnerable.
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Analysis
by VulDB Data Team • 08/18/2025
The vulnerability identified as CVE-2020-1736 represents a significant security flaw within the Ansible Engine's atomic_move primitive functionality. This issue affects multiple stable release branches including 2.7.x, 2.8.x, and 2.9.x, indicating a widespread impact across the Ansible ecosystem. The flaw stems from improper handling of file permissions during atomic move operations, creating potential pathways for unauthorized data access. Security researchers identified this vulnerability through careful analysis of the file system operations performed by Ansible's atomic_move mechanism, which is commonly used for configuration management and deployment tasks.
The technical root cause of this vulnerability lies in the atomic_move primitive's inability to properly specify file modes when moving files between locations. When a destination file does not exist, the primitive defaults to creating it with world-readable permissions, effectively granting any user on the system access to potentially sensitive content. Additionally, when the destination file already exists, the system may modify its permissions to be less restrictive before performing the move operation. This behavior creates a window of opportunity where sensitive data could be exposed to unauthorized users or processes. The vulnerability manifests through the lack of proper permission validation and enforcement during file system operations, which is a fundamental security control that should be maintained throughout all file manipulations.
The operational impact of CVE-2020-1736 extends beyond simple permission issues to encompass potential data disclosure and system compromise scenarios. Organizations utilizing Ansible for configuration management, deployment automation, or infrastructure orchestration may unknowingly expose sensitive information such as configuration files, credentials, or system data through these atomic move operations. The vulnerability particularly affects environments where Ansible is used to manage critical infrastructure components, as the exposure of configuration data could lead to further exploitation opportunities. Attackers could potentially leverage this flaw to gain access to system files, application configurations, or other sensitive artifacts that are typically protected by appropriate file permissions. This represents a direct violation of the principle of least privilege and could enable lateral movement within compromised environments.
Mitigation strategies for CVE-2020-1736 should prioritize immediate patching of affected Ansible versions to the latest stable releases that contain the necessary security fixes. Organizations should conduct comprehensive audits of their Ansible configurations to identify any usage patterns that might be vulnerable to this issue, particularly focusing on atomic_move operations and their associated file permissions. System administrators should implement monitoring controls to detect unusual file permission changes that could indicate exploitation attempts. Additionally, security teams should review and strengthen their overall file system permission policies within Ansible-managed environments. The fix for this vulnerability aligns with common security practices outlined in the CWE-276 standard for improper file permissions, which emphasizes the importance of maintaining appropriate access controls throughout file system operations. Organizations should also consider implementing additional security controls such as privilege separation, regular permission audits, and enhanced logging of file system modifications to reduce the attack surface and improve overall security posture.