CVE-2023-4237: Ansible Automation Platform Info Disclosure

CVE-2023-4237 Overview

A critical information disclosure vulnerability has been identified in the Ansible Automation Platform affecting the ec2_key module. When creating a new keypair, the module prints the private key directly to standard output, allowing attackers with access to log files to retrieve sensitive cryptographic material. This exposure can lead to complete compromise of systems using the leaked keys, affecting confidentiality, integrity, and availability.

Critical Impact

Private cryptographic keys exposed in plaintext through standard output can be captured from log files, enabling unauthorized access to EC2 instances and other AWS resources protected by those keys.

Affected Products

• Red Hat Ansible Automation Platform 2.0
• Red Hat Ansible Collection (all versions)

Discovery Timeline

• 2023-10-04 - CVE-2023-4237 published to NVD
• 2024-11-21 - Last updated in NVD database

Technical Details for CVE-2023-4237

Vulnerability Analysis

This vulnerability is classified under CWE-497 (Exposure of Sensitive System Information to an Unauthorized Control Sphere). The ec2_key module in the Ansible Automation Platform is designed to manage EC2 key pairs in AWS environments. During the keypair creation process, the module outputs the generated private key to stdout without adequate handling or redaction mechanisms.

In typical Ansible deployments, task outputs are captured in various locations including playbook logs, automation controller job logs, and potentially centralized logging systems. When the ec2_key module creates a new key pair, the private key material is included in this output stream, creating a persistent record of sensitive cryptographic credentials that should never be stored or transmitted in plaintext.

Root Cause

The root cause stems from improper handling of sensitive output data within the ec2_key module. The module fails to implement the no_log directive or equivalent output filtering that would prevent private key material from appearing in logs. This design oversight means that any system or user with read access to Ansible logs can potentially retrieve private keys and use them to authenticate to EC2 instances.

Attack Vector

The attack requires local access to systems where Ansible logs are stored. An attacker with read permissions to log files on automation controllers, central log aggregation systems, or even backup archives containing historical logs can extract private keys. Once obtained, these keys can be used to:

• Gain SSH access to EC2 instances provisioned with the compromised key pairs
• Pivot through cloud infrastructure to access additional resources
• Establish persistent access even after the original vulnerability is patched

The vulnerability is particularly dangerous in environments where:

• Logs are stored without adequate access controls
• Multiple administrators have access to automation platforms
• Log files are backed up to less secure storage systems
• Centralized logging aggregates sensitive output across multiple playbooks

Detection Methods for CVE-2023-4237

Indicators of Compromise

• Unexpected SSH connections to EC2 instances from unauthorized IP addresses
• Log file access patterns indicating targeted searches for key-related content
• Historical log files containing BEGIN RSA PRIVATE KEY or similar key markers
• Ansible task logs showing ec2_key module execution with state present

Detection Strategies

• Implement file integrity monitoring on Ansible log directories to detect unauthorized access
• Configure SIEM rules to alert on log file access patterns that include grep or search operations for key-related strings
• Audit SSH authentication logs on EC2 instances for connections using compromised key fingerprints
• Review Ansible Controller job outputs for exposed private key material

Monitoring Recommendations

• Enable detailed access logging for all systems storing Ansible playbook outputs
• Configure CloudTrail to monitor EC2 key pair usage and unexpected instance connections
• Implement network flow analysis to detect unauthorized SSH connections to managed instances
• Establish baseline patterns for legitimate key pair operations and alert on anomalies

How to Mitigate CVE-2023-4237

Immediate Actions Required

• Audit existing Ansible logs for any exposed private key material and rotate affected key pairs immediately
• Implement no_log: true on tasks using the ec2_key module as an interim measure
• Review access controls on all systems storing Ansible execution logs
• Update to patched versions of the affected Ansible collections as specified in Red Hat advisories

Patch Information

Red Hat has released security advisories addressing this vulnerability. Organizations should apply the updates provided in Red Hat Advisory RHBA-2023:5653 and Red Hat Advisory RHBA-2023:5666. Additional details are available in the Red Hat CVE Details and Red Hat Bug Report #2229979.

NetApp customers should also review the NetApp Security Advisory ntap-20241025-0002 for guidance on affected NetApp products.

Workarounds

• Add no_log: true to all tasks utilizing the ec2_key module to prevent output logging
• Implement a wrapper script that captures and redacts sensitive output before logging
• Configure log rotation with short retention periods and secure deletion for sensitive playbook outputs
• Use Ansible Vault or external secrets management for key material instead of relying on ec2_key output

# Example workaround configuration for Ansible playbook
# Add no_log directive to ec2_key tasks
- name: Create EC2 key pair
  amazon.aws.ec2_key:
    name: my-key-pair
    region: us-east-1
  no_log: true
  register: ec2_key_result