CVE-2015-6240 in Ansible
Summary
by MITRE
The chroot, jail, and zone connection plugins in ansible before 1.9.2 allow local users to escape a restricted environment via a symlink attack.
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Analysis
by VulDB Data Team • 12/08/2022
The vulnerability identified as CVE-2015-6240 affects ansible versions prior to 192 and represents a critical security flaw in the chroot jail and zone connection plugins. This issue enables local attackers to bypass restricted execution environments through a carefully crafted symlink attack that exploits weaknesses in how these plugins handle file system operations. The vulnerability specifically targets the privilege escalation mechanisms that ansible employs when establishing connections to target systems through chroot, jail, or zone environments, creating a pathway for unauthorized access to underlying system resources.
The technical root cause of this vulnerability stems from insufficient validation of symbolic link targets within the connection plugin implementations. When ansible executes commands within restricted environments, it relies on predictable file paths and directory structures to maintain isolation boundaries. However, the vulnerable code fails to properly resolve symbolic links before performing operations that should remain confined to the restricted environment. This allows attackers to create malicious symbolic links that point to sensitive system files or directories outside the intended chroot jail or zone boundaries, effectively enabling privilege escalation and information disclosure. The flaw operates at the file system level and leverages the fundamental trust placed in directory structures within containerized or restricted execution contexts.
The operational impact of CVE-2015-6240 extends beyond simple privilege escalation to encompass potential data exfiltration and system compromise across multiple deployment scenarios. Organizations utilizing ansible for configuration management, deployment automation, or orchestration tasks face significant risk when running vulnerable versions, particularly in multi-tenant environments or when executing tasks with elevated privileges. The vulnerability can be exploited by local users who have access to the system where ansible is running, potentially allowing them to gain access to sensitive information stored on the target systems, compromise system integrity, or establish persistent access through the compromised ansible execution environment. This risk is particularly concerning in enterprise environments where ansible is commonly used for managing large fleets of systems with varying security requirements.
Mitigation strategies for CVE-2015-6240 focus primarily on upgrading to ansible version 192 or later, which includes patches that properly validate symbolic link targets within the affected connection plugins. Organizations should also implement additional security controls such as restricting local user access to ansible execution environments, implementing proper file system permissions, and conducting regular security assessments of ansible configurations. The fix addresses the underlying CWE-367 vulnerability category related to time-of-check to time-of-use issues, which is classified under the MITRE ATT&CK framework as a privilege escalation technique. Security teams should also consider implementing monitoring for suspicious symlink creation patterns and establishing baseline configurations that prevent the exploitation of such environment escape vectors. Additional defensive measures include restricting the use of chroot, jail, and zone connection plugins to trusted environments and ensuring that all ansible components are regularly updated to maintain security posture against similar vulnerabilities.