Sr. Staff Security Engineer, Platform Security

Nscale•Seattle, WA

2d•$210,000 - $250,000•Remote

About The Position

Nscale is seeking a Senior Staff Security Engineer to be a founding member of its Platform Security program. This role involves a deep dive into the IaaS platform's actual construction, performing security reviews to identify vulnerabilities and areas for improvement. The focus is on the infrastructure layer, including GPU compute, storage, virtual networking, and Kubernetes. Responsibilities include mapping architecture, defining security standards, reviewing designs and implementations, testing isolation boundaries, and producing assurance evidence. This is a hands-on role requiring significant time spent within the platform, analyzing configurations, tracing data and control paths, and collaborating with engineering teams to implement fixes. Prior experience at a cloud services provider, where the platform is the product, is essential.

Requirements

12+ years in security engineering, platform/infrastructure engineering, or security architecture with a deep platform security focus.
Experience at a cloud services provider, having secured or assessed IaaS services where the platform was the product and tenants were untrusted by default.
Deep understanding of multi-tenant isolation across bare metal, hypervisors, container boundaries, and network segmentation.
Hands-on knowledge of GPU or accelerator infrastructure: passthrough and partitioning, firmware and BMC management, and hardware reuse failure modes.
Strong grasp of storage security in a multi-tenant setting: encryption and key management, access-path control, and data lifecycle across snapshots, backups, and reuse.
Working knowledge of virtual networking: overlay/underlay design, segmentation, and management-plane separation.
Deep knowledge of Kubernetes and container internals, including runtimes, namespaces, cgroups, escape paths, admission control, and workload identity.
Proven ability to influence engineering organizations without direct management, set standards, win arguments with evidence, and drive remediation.
Comfortable operating with ambiguity and a founding-team mandate, creating the evidence base as the program is built.

Nice To Haves

Experience securing or assessing Slurm/HPC environments.

Responsibilities

Perform deep-dive security reviews of Nscale's IaaS services, producing documented architecture, threat models, findings, and remediation plans.
Define security requirements baselines for services and review designs and implementations against them.
Prioritize findings based on exploitability within the Nscale environment.
Advise leadership on platform security gaps and remediation needs.
Review the bare-metal and virtualised GPU compute stack, including host provisioning, hypervisor, GPU passthrough/partitioning, firmware, BMC management, and tenant reprovisioning.
Verify tenant isolation from hardware after lease termination.
Assess the out-of-band management plane and its separation from tenant networks.
Review storage services (block, object, file) for tenant data separation, encryption, key management, and access control.
Verify snapshot, backup, and volume lifecycle handling, including secure deletion and reuse.
Review the virtual network layer, including overlay/underlay design, tenant segmentation, east-west controls, and management plane boundaries.
Test network segmentation under realistic tenant behavior.
Review multi-tenant Kubernetes, including admission control, workload identity, runtime/node hardening, network policy, and container escape paths.
Review Slurm/HPC scheduling for job/tenant isolation, privilege boundaries, and node reuse.
Drive testing of isolation boundaries and gather evidence of customer workload separation.
Partner with platform, SRE, and infrastructure engineering to implement fixes and secure-by-default patterns.
Influence teams without direct management authority.
Track control coverage and remediation trends to quantify security posture.