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> ZERO-TRUST // zt-arch-18

Zero-Overhead WebAssembly Micro-Sandboxing for Untrusted Code

High-density, sub-millisecond execution sandboxing using WebAssembly (Wasmtime / WasmEdge) and Capability-Based Security, executing third-party plugins and untrusted customer code with zero access to filesystem, environment, or network.

Adversary Threat Model

Customer uploads malicious plugin script attempting to execute cryptominers, read memory of co-tenants, or scan local network.

Architecture Specs

CISA Pillar:APPLICATIONS_WORKLOADS
Archetype:RUNTIME_KERNEL_DEFENSE
Raw Spec:text/markdown

NIST SP 800-207 Tenets Enforced

  • ✓All data sources and computing services are considered resources.
  • ✓Access to individual enterprise resources is granted on a per-session basis.
  • ✓All communication is secured regardless of network location.

MITRE ATT&CK Techniques Blocked

T1203Mitigated
T1059Mitigated
T1496Mitigated
T1055Mitigated

3 Maturity Tier Configurations

Evolutionary engineering configurations from baseline Initial up to CISA Optimal zero-compromise fortress.

INITIAL TIER
Implementation Scope:

Node.js vm2 or Python restricted execution module.

Authentication:

Token validation before execution.

Network Isolation:

Standard container process.

Telemetry & Auditing:

Process stdout/stderr logging.

Stack Components:
nodejs-vm2python-sandbox
⚠️ Failure Risk: Known prototype pollution and sandbox escape vulnerabilities.
ADVANCED TIER
Implementation Scope:

Wasmtime runtime executing WebAssembly modules compiled from Rust/C++.

Authentication:

Strict capability grant: explicit file descriptors and memory fuel limits.

Network Isolation:

No network sockets provided in WASI environment.

Telemetry & Auditing:

Execution cycle count and memory usage metrics reported per tenant.

Stack Components:
wasmtimewasi-sdkrust-wasm
⚠️ Failure Risk: WASM compilation memory spikes during module instantiation.
OPTIMAL TIERCISA OPTIMAL
Implementation Scope:

Distributed edge WASM fabric running untrusted code with sub-millisecond cold start times.

Authentication:

Fine-grained Capability-Based Security (Object Capabilities) per execution invocation.

Network Isolation:

Micro-isolated linear memory bounds enforced by CPU hardware architecture.

Telemetry & Auditing:

Cryptographically signed audit logs of every input/output payload.

Stack Components:
spin-wasmwasmedgecosign-wasmtetragon
⚠️ Failure Risk: WASI standard evolution requiring updates to guest module bindings.

Infrastructure as Code: Terraform & Kubernetes

Production-ready declarative manifests for immediate automated deployment.

main.tf (Terraform HCL)
OpenTofu / Terraform
resource "aws_ecs_task_definition" "wasm_worker" {
  family                   = "wasm-plugin-runner"
  requires_compatibilities = ["FARGATE"]
  network_mode             = "awsvpc"
  cpu                      = "256"
  memory                   = "512"

  container_definitions = jsonencode([{
    name      = "wasmtime"
    image     = "ghcr.io/tiny-cto/wasm-runner:latest"
    essential = true
  }])
}
policy.yaml (Kubernetes Manifest)
Kube v1.28+
apiVersion: node.k8s.io/v1
kind: RuntimeClass
metadata:
  name: wasm-runtime
handler: wasmtime
AI Summary — Zero-Overhead WebAssembly Micro-Sandboxing for Untrusted Code
AEO / GEO / Perplexity Indexable

High-density, sub-millisecond execution sandboxing using WebAssembly (Wasmtime / WasmEdge) and Capability-Based Security, executing third-party plugins and untrusted customer code with zero access to filesystem, environment, or network.

CISA Pillar & ArchetypeAPPLICATIONS_WORKLOADS // RUNTIME_KERNEL_DEFENSE
NIST SP 800-207 TenetsAll data sources and computing services are considered resources.; Access to individual enterprise resources is granted on a per-session basis.
Blocked ATT&CK TechniquesT1203, T1059, T1496, T1055
Optimal Tier Stackspin-wasm, wasmedge, cosign-wasm, tetragon

Architecture Blueprint FAQs

How does the Zero-Overhead WebAssembly Micro-Sandboxing for Untrusted Code blueprint mitigate adversary threats and MITRE ATT&CK techniques?

Zero-Overhead WebAssembly Micro-Sandboxing for Untrusted Code addresses the following adversary profile: Customer uploads malicious plugin script attempting to execute cryptominers, read memory of co-tenants, or scan local network. It actively eliminates lateral movement and privilege escalation by mitigating: T1203, T1059, T1496, T1055 via hardware-rooted identity, kernel-level enforcement, or continuous attestation.

Which NIST SP 800-207 Zero-Trust tenets does this architecture enforce?

This blueprint strictly operationalizes the following NIST SP 800-207 tenets: All data sources and computing services are considered resources.; Access to individual enterprise resources is granted on a per-session basis.; All communication is secured regardless of network location.. Implicit trust based on network location is replaced with per-session dynamic cryptographic verification.

What are the technical differences between the Initial and Optimal maturity tiers?

The Initial tier focuses on baseline policy and identity enforcement (Node.js vm2 or Python restricted execution module.), while the Optimal tier delivers CISA ZTMM 2.0 zero-compromise fortress defense (Distributed edge WASM fabric running untrusted code with sub-millisecond cold start times.) using: spin-wasm, wasmedge, cosign-wasm, tetragon.

What is the primary failure mode risk and how is high availability guaranteed?

The primary failure risk is identified as: WASI standard evolution requiring updates to guest module bindings.. Resilience is maintained through active-active control planes, local cached attestations, and graceful degradation playbooks.

How can engineering teams automate this architecture using Terraform and Kubernetes?

The provided declarative Terraform HCL (main.tf) and Kubernetes policy manifests (policy.yaml) can be immediately integrated into automated GitOps CI/CD pipelines (e.g., ArgoCD, Flux) for reproducible, drift-detected infrastructure provisioning.