: Ensure that your applications only make requests to the metadata server when absolutely necessary and that they do not expose raw metadata responses to users.
The string you provided—once URL-decoded—translates to: http://metadata.google.internal/computeMetadata/v1/instance/service-accounts/
Buckets of Fun: Getting Backstage at the DEFCON 31 Cloud ...
default/ my-app@my-project.iam.gserviceaccount.com/ : Ensure that your applications only make requests
When an application or logging system records an action, it often sanitizes or URL-encodes special characters. Breaking down the specific parts of this signature helps explain what an attacker or an internal automated process is attempting to do: Introduction to service identity | Cloud Run
The fetch URL in question, http://metadata.google.internal/computeMetadata/v1/instance/service-accounts/ , can be broken down into several components:
Zero transformed the URL into a slurry of characters that the WAF wouldn't recognize as a threat, but the underlying server would eventually decode. Breaking down the specific parts of this signature
.../default/email : Retrieves the email address of the primary service account.
Going Above and Beyond: Downloading ALL the Buckets * Fetches an access token through the vulnerable Cloud Run app, * Lists the av... blog.ctis.me Soluciona problemas de acceso del servidor de metadatos
One Tuesday, Query received a high-priority task. He needed to prove he was authorized to access a guarded database. To do that, he needed his "Identity Card"—a service account token. or network policies are blocking access.
The keyword refers to a URL-encoded request directed at the Google Cloud Platform (GCP) Instance Metadata Service (IMDS) . Specifically, it targets the directory containing information about the service accounts attached to a virtual machine (VM). Understanding the URL Structure
| Error | Likely Cause | Solution | | :--- | :--- | :--- | | 403 Forbidden | Missing the Metadata-Flavor: Google header in your request. | Add the header to your request: curl -H "Metadata-Flavor: Google" ... | | 400 Bad Request | Requesting a specific scope that wasn't granted to the service account at instance creation time. | Ensure the required API scope is enabled when creating your VM. | | Invalid response from metadata service: incorrect Metadata-Flavor header | A client library or application is failing to add the required header. | Update your client library to the latest version or manually add the header in custom HTTP requests. | | Connection timeout or Unable to connect (trying to reach 169.254.169.254 ) | The code is not running on a Google Cloud resource, or network policies are blocking access. | The metadata server is only accessible from within Google Cloud environments. Check your firewall rules, network policies, and instance configurations. |
The log entry read: ERROR: Request failed for fetch-url-http-3A-2F-2Fmetadata.google.internal-2FcomputeMetadata-2Fv1-2Finstance-2Fservice-accounts-2F
curl -H "Metadata-Flavor: Google" \ "http://metadata.google.internal/computeMetadata/v1/instance/service-accounts/default/token"