Fetch-url-http-3a-2f-2fmetadata.google.internal-2fcomputemetadata-2fv1-2finstance-2fservice Accounts-2f Page

To "prepare a feature" around this functionality, you are likely looking to either implement a legitimate data-fetching mechanism for a VM or build a security-focused feature to detect or prevent SSRF attacks. 1. Functional Feature: Service Account Metadata Fetcher

Every Compute Engine VM, GKE node, Cloud Run revision, and many other GCP serverless environments run a local at the non‑routable IP address 169.254.169.254 and the hostname metadata.google.internal . This server exposes a REST API over HTTP (no TLS required, because the traffic never leaves the physical host). It provides:

.../scopes : Lists the access scopes granted to the service account. 2. Security Feature: SSRF Prevention

Understanding this mechanism is crucial for GCP security, infrastructure automation, and workload authentication. To "prepare a feature" around this functionality, you

If you are seeing this in an error message (e.g., "Failed to fetch URL"), it is often because of a missing header.

: It is most commonly used to programmatically retrieve OAuth2 access tokens or OpenID Connect (OIDC) identity tokens . These tokens allow your code to authenticate with other Google Cloud APIs (like Storage or BigQuery) without hardcoding credentials.

Each entry is a directory containing metadata about that service account. Typically, every GCE instance has at least the . This server exposes a REST API over HTTP

You will find sub-paths like:

Using the Google Cloud Go Client or standard Python requests library:

If your goal is to programmatically retrieve service account information (like OAuth2 tokens) from within a GCP instance, follow these standard query methods: and—the main goal—the access tokens. A.

When you attach a service account to a VM, the metadata server generates an endpoint to manage it. This endpoint allows you to retrieve the email address of the default service account, its aliases, and—the main goal—the access tokens. A. Core Endpoints http://google.internal Default Service Account Details: http://google.internal Default Service Account Token: http://google.internal B. The Metadata-Flavor Header

curl -H "Metadata-Flavor: Google" \ "http://metadata.google.internal/computeMetadata/v1/instance/service-accounts/" \ | tr '/' '\n'

This adheres to the principle of least privilege and is a crucial security practice.