CVE-2020-1740 in Ansible Engine
Summary
by MITRE
A flaw was found in Ansible Engine when using Ansible Vault for editing encrypted files. When a user executes "ansible-vault edit", another user on the same computer can read the old and new secret, as it is created in a temporary file with mkstemp and the returned file descriptor is closed and the method write_data is called to write the existing secret in the file. This method will delete the file before recreating it insecurely. 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 • 05/10/2025
The vulnerability identified as CVE-2020-1740 represents a critical security flaw in Ansible Engine's handling of encrypted files through Ansible Vault functionality. This issue specifically affects the ansible-vault edit command execution process where temporary file management creates exploitable conditions for unauthorized information disclosure. The flaw manifests when users attempt to edit encrypted files using the ansible-vault edit command, creating a scenario where concurrent users on the same system can potentially access sensitive data that should remain protected.
The technical implementation of this vulnerability stems from improper temporary file handling within the Ansible Vault editing process. When the ansible-vault edit command is executed, the system utilizes mkstemp to create temporary files but fails to maintain proper security controls throughout the file lifecycle. The vulnerability occurs because the method write_data is called to write existing secrets into the temporary file, yet this method deletes the existing file before recreating it in an insecure manner. This deletion and recreation process creates a window of opportunity where the temporary file exists in a state accessible to other users on the same system, allowing for potential information leakage.
The operational impact of this vulnerability extends beyond simple information disclosure, creating a serious threat to system security in multi-user environments. Attackers can exploit this weakness by creating a race condition where they monitor for temporary files created during the vault editing process and then read the contents before the file is properly secured or deleted. This vulnerability affects all versions within the 2.7.x, 2.8.x, and 2.9.x branches of Ansible Engine, indicating a widespread exposure across multiple stable release lines. The flaw directly relates to CWE-377, which addresses insecure temporary file creation practices, and aligns with ATT&CK technique T1552.001 for unsecured credentials storage, as it exposes encrypted secrets during the editing process.
The security implications of this vulnerability are particularly severe in shared computing environments where multiple users may have access to the same system. System administrators and security professionals should consider this vulnerability as a critical threat vector for any organization using Ansible for configuration management or automation tasks. The flaw essentially undermines the security guarantees provided by Ansible Vault encryption, potentially exposing sensitive credentials, passwords, and other confidential information that should remain protected during the editing process. Organizations should immediately implement mitigations including updating to patched versions of Ansible Engine, implementing additional monitoring for temporary file access patterns, and considering alternative secure editing approaches for sensitive configurations.
This vulnerability demonstrates the importance of proper temporary file management in security-sensitive applications and highlights how seemingly minor implementation details can create significant security weaknesses. The flaw represents a classic example of insecure file handling that can be exploited by attackers with local system access, making it particularly dangerous in environments where privilege separation is not properly enforced. Security teams should prioritize patching this vulnerability across all affected Ansible installations and conduct thorough assessments of their Ansible automation workflows to ensure no sensitive data has been compromised through this vulnerability.