CVE-2023-3072 in Nomad
Summary
by MITRE • 07/20/2023
HashiCorp Nomad and Nomad Enterprise 0.7.0 up to 1.5.6 and 1.4.10 ACL policies using a block without a label generates unexpected results. Fixed in 1.6.0, 1.5.7, and 1.4.11.
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Analysis
by VulDB Data Team • 08/15/2023
The vulnerability identified as CVE-2023-3072 affects HashiCorp Nomad and Nomad Enterprise versions ranging from 0.7.0 through 1.5.6 and 1.4.10, representing a critical flaw in access control list policy evaluation. This issue specifically manifests when ACL policies contain blocks without explicit labels, creating unpredictable behavior in permission enforcement mechanisms. The flaw stems from how the system processes policy definitions that lack proper labeling, leading to potential privilege escalation or unauthorized access scenarios within containerized orchestration environments. The vulnerability impacts organizations relying on Nomad's security controls for managing workloads and access permissions across distributed systems.
The technical implementation of this vulnerability resides in Nomad's ACL policy parsing and evaluation engine where the absence of labels in policy blocks causes the system to misinterpret access control rules. When an ACL policy contains a block without a label, the parser fails to properly associate the policy constraints with the intended resources or operations, resulting in either overly permissive access or complete denial of legitimate requests. This behavior violates fundamental security principles and creates a condition where administrators cannot reliably predict or control access permissions. The issue operates at the policy evaluation layer, making it particularly dangerous as it affects the core security mechanisms that protect Nomad clusters and their workloads from unauthorized access.
The operational impact of this vulnerability extends beyond simple access control failures, potentially enabling attackers to gain elevated privileges or bypass security controls entirely. Organizations using affected versions of Nomad may experience unauthorized access to cluster resources, including the ability to submit jobs, view sensitive information, or modify system configurations. The unpredictable nature of the vulnerability means that security controls may fail silently, allowing malicious actors to operate undetected within the system. This risk is particularly severe in multi-tenant environments where proper isolation between different users or teams depends on accurate ACL enforcement. The vulnerability also affects Nomad Enterprise customers who rely on advanced access control features for compliance and security governance purposes.
Mitigation strategies for CVE-2023-3072 require immediate deployment of patched versions 1.6.0, 1.5.7, or 1.4.11, depending on the specific Nomad version in use. Organizations should conduct comprehensive audits of existing ACL policies to identify and remediate any blocks lacking proper labels, ensuring all policy definitions include explicit labels for accurate evaluation. System administrators should implement monitoring for unusual access patterns that might indicate exploitation attempts, particularly around authentication and authorization events. The vulnerability aligns with CWE-284 Access Control Issues and maps to ATT&CK technique T1078 Valid Accounts, as it could enable unauthorized access through compromised or misconfigured access controls. Organizations should also review their overall security posture and implement additional layers of protection including network segmentation, privileged access management, and regular security assessments to prevent exploitation of similar access control vulnerabilities in other components of their infrastructure.