A critical OS command injection vulnerability in the Amazon ECS Agent for Windows allows authenticated attackers to achieve full SYSTEM-level code execution on the underlying host.

This is an OS command injection flaw (CWE-78) where improper neutralization of inputs in the FSx Windows File Server volume mounting component allows an authenticated user with permissions to register ECS task definitions or modify sensitive credential stores to execute arbitrary shell commands.

The ability to execute commands with SYSTEM privileges grants an attacker total control over the host operating system, leading to potential data exfiltration, lateral movement within the AWS environment, and complete system compromise. With a CVSS score of 7.2, this vulnerability represents a significant risk to infrastructure integrity and confidentiality, particularly for organizations relying on ECS for container orchestration.

Immediate Action: Upgrade the Amazon ECS Agent on all affected Windows nodes to version 1.103.0 or later to resolve the injection vulnerability.

Proactive Monitoring: Review audit logs for unusual task definition registrations or unauthorized modifications to Secrets Manager and SSM Parameter Store entries associated with FSx volume configurations.

Compensating Controls: Restrict permissions for registering ECS task definitions and access to credential stores to a minimal set of highly trusted administrative accounts to reduce the attack surface.

Public Exploit Available: Unknown.

Given the potential for full SYSTEM-level compromise, organizations must prioritize the update to version 1.103.0 across all Windows-based ECS clusters. Administrators should also audit their IAM policies and service permissions to ensure the principle of least privilege is strictly enforced for ECS task management.