CVE-2021-4112 in Ansible Tower
Summary
by MITRE • 08/26/2022
A flaw was found in ansible-tower where the default installation is vulnerable to job isolation escape. This flaw allows an attacker to elevate the privilege from a low privileged user to an AWX user from outside the isolated environment.
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Analysis
by VulDB Data Team • 08/26/2022
The vulnerability identified as CVE-2021-4112 represents a critical privilege escalation flaw within the ansible-tower application, specifically affecting the job isolation mechanism that is fundamental to the security architecture of the platform. This vulnerability exists in the default installation configuration where the job isolation feature fails to properly enforce security boundaries, creating a pathway for unauthorized privilege elevation. The flaw manifests when an attacker operating from outside the isolated execution environment can exploit the compromised isolation controls to escalate their privileges from a low-privileged user status to that of an AWX user, effectively bypassing the intended security boundaries that should protect the system from external interference.
The technical implementation of this vulnerability stems from insufficient access controls and inadequate sandboxing mechanisms within the job execution framework of ansible-tower. When jobs are executed in isolated environments, the system should enforce strict boundary controls that prevent unauthorized access to system resources and user privileges. However, the flaw in CVE-2021-4112 demonstrates that these isolation mechanisms are insufficiently configured or implemented, allowing external attackers to manipulate job execution contexts and gain elevated privileges. This vulnerability is particularly concerning because it directly impacts the core security model of the platform, where job isolation is designed to prevent privilege escalation and maintain system integrity. The flaw operates at the intersection of inadequate privilege separation and weak environmental boundary controls, creating a scenario where attackers can manipulate the job execution environment to gain unauthorized access to higher privilege levels.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it fundamentally undermines the security architecture that ansible-tower relies upon for protecting sensitive automation workflows and system resources. Attackers exploiting this vulnerability can potentially access confidential automation tasks, manipulate job execution parameters, and gain access to system resources that should remain restricted to authorized users. The implications are particularly severe in enterprise environments where ansible-tower is used for critical infrastructure automation, as this vulnerability could enable attackers to compromise automated deployment processes and gain access to production environments. This flaw also affects the integrity of the automation pipeline, as it allows unauthorized modifications to job execution contexts that could lead to further exploitation opportunities and persistent access to the system.
Mitigation strategies for CVE-2021-4112 should focus on strengthening the job isolation mechanisms and implementing proper access controls that enforce strict boundary enforcement between isolated and non-isolated environments. Organizations should immediately update to patched versions of ansible-tower where the job isolation controls have been properly implemented and configured. Security configurations should be reviewed to ensure that isolation boundaries are properly enforced and that default installations do not expose unnecessary privileges to external attackers. Network segmentation and access controls should be implemented to restrict access to the job execution environments, while monitoring systems should be enhanced to detect unauthorized privilege escalation attempts. This vulnerability aligns with CWE-284, which addresses improper access control, and maps to ATT&CK technique T1068, which covers privilege escalation through local exploitation, though in this case the escalation occurs through network-based attack vectors rather than local system compromise.