ExtBit Security Specification: Ephemeral Sandboxing & Supply Chain Protection

1Overview

This policy dictates the strict security standards for ingesting, reviewing, and building external client codebases. The central objective of this protocol is preventing the unauthorized execution of hidden scripts, malicious hooks, or embedded binary programs. While building UI/UX prototypes using ecosystems like Node.js is a common scenario, these guidelines apply universally to all third-party code interactions to protect ExtBit's infrastructure.

2Mandatory Isolation & Execution Prevention

2.1Ephemeral Sandboxing

• Client code must never be cloned, stored, or built directly on ExtBit host operating systems.
• All operations must occur within heavily restricted, ephemeral virtual machines or containers that have zero access to ExtBit's internal network routing.
• Strict Egress Filtering: Outbound internet access from the sandbox must be blocked or strictly whitelisted to prevent secondary malware payloads from downloading or environment variables from being exfiltrated.
• Resource Quotas: Ephemeral containers must have strict CPU and memory limits applied to prevent denial-of-service (DoS) attacks via fork bombs or infinite loops hidden in client code.

2.2Neutralizing Git Vectors (.git/hooks)

• Version control systems are primary vectors for supply chain attacks. Git repositories can harbor malicious executables within the `.git/hooks` directory. These can trigger arbitrary code execution automatically upon performing standard operations (e.g., `clone`, `checkout`, `commit`).
• Policy: All initial Git clones must aggressively bypass local template initializations to neutralize malicious hooks.

    git clone --template=/dev/null <repository-url>
  

• Submodule Blind Spots: Never use the `--recurse-submodules` flag during the initial clone. Submodules must be treated as independent, untrusted entities and evaluated through this exact same zero-trust pipeline.

3Advanced Container & Runtime Security

3.1Supported Runtimes and OS-Level Virtualization

• Linux Environments: Standardize on rootless container runtimes (e.g., Podman or Rootless Docker). The Docker daemon must never run as root when evaluating client code.
• macOS/Apple Environments: When evaluating iOS/macOS codebases or utilizing Apple Silicon, environments must be isolated using Apple's Virtualization framework or native macOS containers. Direct execution on the host macOS kernel is strictly prohibited.

3.2Runtime Hardening Protocols

• Privilege Dropping: Containers must never be run with the `--privileged` flag. Drop all unnecessary Linux capabilities (e.g., `--cap-drop=ALL`).
• Read-Only Filesystems: Mount the container's root filesystem as read-only (`--read-only`). Volatile data required for builds must be restricted to scoped, temporary `tmpfs` mounts.
• Interactive Shell Prohibition: Once a codebase is pulled and the container is built for evaluation, interactive shell access (e.g., `docker exec -it <container> /bin/bash`) is strictly disabled to prevent accidental tampering or lateral movement by internal staff.

4Build Systems & Dependency Management

4.1The JavaScript / Node.js Threat Landscape (Example)

• Dynamic package ecosystems (e.g., Node/NPM, PyPI, Cargo) present broad supply chain attack surfaces, particularly via third-party dependency resolution and unvetted lifecycle scripts (postinstall).
• When evaluating JavaScript applications or building UI/UX prototypes, dependencies must be installed deterministically and with lifecycle scripts strictly disabled.

    npm ci --ignore-scripts
  

• Universal Rule: This core principle extends to all package managers (e.g., Pip, Maven, Cargo). Automatic script execution during dependency resolution is strictly prohibited unless actively reverse-engineering malware in an air-gapped sandbox.

5Data Privacy & Mock Data Handling

5.1Prohibition of Production Data

• Client codebases provided for evaluation or prototyping must never include live database dumps, real user credentials, Personally Identifiable Information (PII), or Protected Health Information (PHI).

5.2Synthetic Data Mandate

• Any data utilized to populate UI/UX prototypes or run local databases during evaluation must be strictly synthetic or heavily sanitized mock data provided explicitly for non-production use.

6Environment Lifecycle & Auditing

6.1Hard Time-to-Live (TTL)

• Ephemeral sandboxes must be configured with a hard Time-to-Live (TTL) (e.g., a maximum of 4 to 8 hours) before automatically self-destructing. This prevents orphaned containers from serving as persistent staging grounds for malicious actors.

6.2Strict RBAC for Instantiation

• Sandboxes may only be provisioned and instantiated by specific, authorized Identity and Access Management (IAM) roles within ExtBit, enforcing the principle of least privilege among internal staff.

6.3Immutable Audit Logging

• All actions—including the initial clone request, environment instantiation, automated scanning results, and sandbox destruction—must be forwarded to an immutable, centralized logging server for compliance and forensic auditing.

7Intake Scanning and Data Destruction

7.1Secret and Binary Scanning

• Upon intake, automated scanners must immediately parse the repository for leaked client secrets and hidden compiled binaries.
• ExtBit personnel must not execute any found binary objects under any circumstances.
• Incident Escalation: Any discovered binary objects or highly suspicious executable scripts must be immediately quarantined and logged to the Security Operations Center (SOC) for forensic documentation.

7.2Secure Purging

• Upon project completion (or TTL expiration), all ephemeral environments, build caches (e.g., `.npm`, `.git`), and local storage volumes must be cryptographically wiped and destroyed.

August 26, 2026