CVE-2023-1782: 
Nomad vulnerability analysis and mitigation

HashiCorp Nomad and Nomad Enterprise versions 1.5.0 through 1.5.2 contain a vulnerability (CVE-2023-1782) that allows unauthenticated users to bypass intended ACL authorizations in clusters where mTLS is not enabled. The vulnerability was discovered by HashiCorp's Security and Solutions Engineering teams and was fixed in version 1.5.3 (HashiCorp Discussion).

The vulnerability exists in the client agent's HTTP endpoint processing mechanism. When an unauthenticated request is sent to a client agent's HTTP endpoint, it bypasses the intended ACL authorizations when processed on the server through internal RPCs. This affects both HTTP (port 4646) and RPC (port 4647) endpoints, which are normally used for internal Nomad communication and administrative interactions (HashiCorp Discussion).

The vulnerability allows unauthenticated users to submit jobs to the cluster if mTLS is not enabled. This could potentially lead to unauthorized access and privilege escalation within the Nomad cluster (HashiCorp Discussion).

HashiCorp recommends upgrading to Nomad version 1.5.3 or newer to address this vulnerability. Additionally, administrators should always implement mTLS for both HTTP and RPC endpoints as part of their security model. Detailed upgrade guidance is available in Nomad's upgrading documentation (HashiCorp Discussion).