CVE-2013-4259 in Ansible
Summary
by MITRE
runner/connection_plugins/ssh.py in Ansible before 1.2.3, when using ControlPersist, allows local users to redirect a ssh session via a symlink attack on a socket file with a predictable name in /tmp/.
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Analysis
by VulDB Data Team • 01/07/2022
The vulnerability identified as CVE-2013-4259 represents a critical security flaw in Ansible's SSH connection plugin implementation that affects versions prior to 1.2.3. This issue specifically targets the ControlPersist functionality within Ansible's runner system, where the software creates socket files with predictable naming patterns in the /tmp directory. The vulnerability arises from insufficient validation of socket file paths during SSH session establishment, creating an opportunity for local privilege escalation through symlink manipulation attacks.
The technical exploitation of this vulnerability occurs when Ansible's ssh.py connection plugin creates socket files in /tmp with predictable names such as ansible-ssh-*. When a local attacker can predict these filenames, they can establish symbolic links that redirect the SSH session to an attacker-controlled socket file. This allows the attacker to intercept or manipulate SSH communications, potentially gaining unauthorized access to systems that would normally be protected by proper authentication mechanisms. The flaw is classified under CWE-310 as "Cryptographic Vulnerability" and specifically relates to improper handling of temporary files and predictable naming conventions.
The operational impact of CVE-2013-4259 extends beyond simple privilege escalation to encompass potential data interception and system compromise. When local users can manipulate SSH socket files, they can capture authentication credentials, execute arbitrary commands on target systems, or establish persistent backdoors through the compromised SSH sessions. This vulnerability particularly affects environments where Ansible is used for system administration tasks, as it undermines the trust model of SSH-based authentication and can be exploited to gain elevated privileges on managed systems. The attack vector aligns with ATT&CK technique T1078.004 for Valid Accounts and T1566.001 for Phishing, as it leverages legitimate system administration tools to bypass security controls.
Mitigation strategies for CVE-2013-4259 primarily involve upgrading to Ansible version 1.2.3 or later, which includes proper socket file validation and randomization of socket naming conventions. Organizations should also implement additional security controls such as restricting write access to /tmp directories for non-privileged users, monitoring for suspicious symlink creation patterns, and ensuring that SSH ControlPersist features are properly configured with appropriate security settings. System administrators should regularly audit Ansible configurations to verify that socket file creation occurs in secure temporary locations with proper permissions and that predictable naming patterns are eliminated from the implementation. The vulnerability demonstrates the importance of proper temporary file handling in automation tools and the need for comprehensive security testing of system administration frameworks.