CVE-2020-10709 in Ansible Tower
Summary
by MITRE • 05/28/2021
A security flaw was found in Ansible Tower when requesting an OAuth2 token with an OAuth2 application. Ansible Tower uses the token to provide authentication. This flaw allows an attacker to obtain a refresh token that does not expire. The original token granted to the user still has access to Ansible Tower, which allows any user that can gain access to the token to be fully authenticated to Ansible Tower. This flaw affects Ansible Tower versions before 3.6.4 and Ansible Tower versions before 3.5.6.
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Analysis
by VulDB Data Team • 08/22/2022
The vulnerability described in CVE-2020-10709 represents a critical authentication flaw within Ansible Tower's OAuth2 implementation that fundamentally undermines the security model of the platform. This issue manifests when users request OAuth2 tokens through OAuth2 applications, creating a scenario where attackers can exploit the system to obtain refresh tokens that remain valid indefinitely. The flaw specifically targets the token management system that Ansible Tower employs for user authentication, creating a persistent security risk that extends far beyond the typical expiration mechanisms designed to protect against unauthorized access. The vulnerability exists in versions prior to 3.6.4 and 3.5.6, indicating that organizations running these older versions face significant exposure to potential attacks.
The technical nature of this flaw stems from improper token lifecycle management within Ansible Tower's OAuth2 framework, where refresh tokens are not being properly validated for expiration. According to CWE-284, this represents an improper access control vulnerability where the system fails to properly restrict access to privileged resources. The flaw allows attackers to obtain tokens that bypass normal authentication mechanisms, creating a persistent backdoor into the Ansible Tower environment. When users receive OAuth2 tokens, the system should enforce strict token expiration policies and proper revocation mechanisms, but this vulnerability enables attackers to maintain indefinite access to the platform.
The operational impact of CVE-2020-10709 extends beyond simple unauthorized access, as it provides attackers with complete administrative capabilities within the Ansible Tower environment. This vulnerability directly maps to ATT&CK technique T1566, which involves credential access through social engineering or exploitation of authentication systems, and T1078, which covers valid accounts usage. Once an attacker obtains an unexpired refresh token, they can impersonate any user within the system indefinitely, potentially gaining access to sensitive configuration data, deployment credentials, and operational controls. The persistence aspect of this vulnerability means that even if users change their passwords or revoke tokens, the attacker can continue to operate undetected within the system, making it particularly dangerous for organizations that rely on Ansible Tower for infrastructure automation and deployment management.
Organizations affected by this vulnerability should immediately implement mitigation strategies including updating to Ansible Tower versions 3.6.4 or 3.5.6, which contain the necessary patches to address the token expiration flaw. Security teams must also conduct comprehensive token revocation across all affected systems and implement monitoring for unauthorized token usage patterns. The vulnerability demonstrates the critical importance of proper token management and expiration policies in authentication systems, aligning with security best practices outlined in NIST SP 800-63B for digital identity management. Additionally, organizations should consider implementing additional authentication layers such as multi-factor authentication and continuous monitoring of token usage to detect and prevent exploitation of similar vulnerabilities in the future.