CVE-2024-9902 is an authorization flaw discovered in the ansible-core user module, affecting versions from 0 up to 2.18.0b1. The vulnerability arises because the module allows an unprivileged user to silently create or replace the contents of any file on any system path and assume ownership of that file when a privileged user executes the user module targeting the unprivileged user's home directory. This occurs if the unprivileged user has directory traversal permissions on the directory containing the targeted file. The flaw enables the unprivileged user to manipulate files that should be protected, potentially leading to unauthorized code execution or privilege escalation. The attack vector requires local access with low privileges, high attack complexity due to the need for specific directory permissions, and user interaction since a privileged user must run the module. The vulnerability impacts confidentiality and integrity significantly, as attackers can alter critical files, but availability impact is low. No public exploits have been reported yet, but the risk remains due to the widespread use of Ansible in automation and configuration management. The vulnerability was published on November 6, 2024, and assigned a CVSS v3.1 score of 6.3 (medium severity), reflecting the balance between impact and exploitation complexity.

For European organizations, this vulnerability poses a significant risk to the confidentiality and integrity of systems managed via Ansible. Attackers with local unprivileged access could manipulate critical configuration or system files by exploiting the flaw during privileged Ansible runs, potentially leading to privilege escalation or persistent backdoors. This is particularly concerning for organizations relying heavily on Ansible for automated configuration management, including cloud providers, financial institutions, and critical infrastructure operators. The ability to silently replace files and gain ownership undermines trust in automated deployments and could facilitate lateral movement within networks. Although no known exploits exist in the wild, the vulnerability's presence in multiple beta versions suggests that organizations using pre-release or early versions are at increased risk. The requirement for user interaction and specific directory permissions somewhat limits the attack surface but does not eliminate the threat in environments with complex permission structures or shared systems.

European organizations should immediately audit their Ansible deployments to identify usage of affected versions (0 through 2.18.0b1) and upgrade to patched versions once available. Until patches are released, restrict directory traversal permissions for unprivileged users, especially on directories containing sensitive files or home directories targeted by Ansible user module operations. Implement strict access controls and monitoring on systems running Ansible automation to detect unusual file modifications or ownership changes. Limit the execution of privileged Ansible modules to trusted administrators and consider isolating Ansible control nodes from untrusted users. Employ file integrity monitoring tools to alert on unauthorized changes to critical system files. Additionally, review and harden Ansible playbooks to avoid executing user module commands on untrusted directories. Conduct regular security training for administrators to recognize and prevent risky operational practices that could facilitate exploitation.