CVE-2023-1296 in Nomad
Summary
by MITRE • 03/14/2023
HashiCorp Nomad and Nomad Enterprise 1.4.0 up to 1.5.0 did not correctly enforce deny policies applied to a workload’s variables. Fixed in 1.4.6 and 1.5.1.
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Analysis
by VulDB Data Team • 04/07/2023
HashiCorp Nomad and Nomad Enterprise versions 1.4.0 through 1.5.0 contained a critical authorization flaw that allowed workloads to bypass deny policies applied to their variables. This vulnerability represents a failure in the access control mechanisms that should have prevented unauthorized access to sensitive configuration data. The flaw specifically affected the enforcement of deny policies within the variable system, where workloads could potentially read or manipulate variables that should have been restricted based on policy configurations. This issue stems from inadequate validation of variable access controls during workload execution, creating a path for privilege escalation and unauthorized data exposure. The vulnerability aligns with CWE-284 which addresses improper access control, and specifically relates to the failure to enforce mandatory access controls on resource variables within containerized environments.
The technical implementation of this flaw allowed malicious or compromised workloads to circumvent the intended deny policies that should have restricted variable access. Nomad's variable system typically supports hierarchical access controls where policies define which workloads can access specific variables, but the vulnerability enabled workloads to access variables that were explicitly denied through policy configurations. This weakness occurred during the variable resolution process, where the system failed to properly validate access permissions before allowing variable expansion or reference. The impact was particularly severe because Nomad workloads often contain sensitive credentials, configuration parameters, and environment-specific data that should remain protected from unauthorized access. Attackers could exploit this by crafting workloads that attempt to reference denied variables, potentially gaining access to secrets, database credentials, or other sensitive information stored in Nomad's variable system.
The operational impact of this vulnerability extends beyond simple data exposure, as it fundamentally undermines the security posture of Nomad deployments that rely on variable-based access control. Organizations using Nomad for container orchestration and job scheduling could experience unauthorized access to sensitive operational data, potentially leading to credential theft, data breaches, or lateral movement within their infrastructure. The vulnerability affects both standard Nomad installations and Nomad Enterprise deployments, indicating it was a core architectural flaw in the variable access control implementation. This flaw particularly impacts environments where workloads are managed by untrusted or compromised entities, as the bypass mechanism could enable attackers to escalate privileges and access additional system resources. The issue also creates potential for privilege escalation attacks where a workload with limited access could gain access to variables containing administrative credentials or system-level configuration data.
Mitigation strategies for this vulnerability require immediate deployment of the patched versions 1.4.6 and 1.5.1, which contain the necessary fixes to properly enforce deny policies on workload variables. Organizations should conduct thorough audits of their Nomad variable configurations to identify any workloads that may have been exploiting the vulnerability, particularly focusing on variable access policies that control sensitive data access. Security teams should implement monitoring for unauthorized variable access attempts and establish incident response procedures for potential exploitation. The fix addresses the underlying access control validation mechanism, ensuring that deny policies are properly enforced during variable resolution processes. Additionally, organizations should consider implementing additional security controls such as variable encryption, access logging, and regular policy reviews to strengthen their overall security posture. This vulnerability highlights the importance of proper access control implementation in container orchestration platforms and the critical need for comprehensive security testing of authorization mechanisms. The remediation process should include validating that all variable policies are properly enforced and that no workloads can bypass access restrictions through similar mechanisms.