Overview of app security

Security is a core feature of the Google Cloud, but there are still steps you should take to protect your App Engine app and identify vulnerabilities.

Use the following features to ensure that your App Engine app is secure. To learn more about the Google Security Model and the available steps that you can take to secure your Google Cloud projects, see Google Cloud Security.

HTTPS requests

Use HTTPS requests to access to your App Engine app securely. Depending on how your app is configured, you have the following options:

appspot.com domains

• Use the https URL prefix to send HTTPS request to the default service of your Google Cloud project, for example:
  https://PROJECT_ID.REGION_ID.r.appspot.com

• To target specific resources in your App Engine app, use the -dot- syntax to separate each resource you want to target, for example:
  https://VERSION-dot-SERVICE-dot-PROJECT_ID.REGION_ID.r.appspot.com

• To convert an HTTP URL to an HTTPS URL, replace the periods between each resource with -dot-, for example:
  http://SERVICE_ID.PROJECT_ID.REGION_ID.r.appspot.com
https://SERVICE_ID-dot-PROJECT_ID.REGION_ID.r.appspot.com

For more information about HTTPS URLs and targeting resources, see How Requests are Routed.

Custom domains

To send HTTPS requests with your custom domain, you can use the managed SSL certificates that are provisioned by App Engine. For more information, see Securing Custom Domains with SSL.

Access control

In each Google Cloud project, set up access control to determine who can access the services within the project, including App Engine. You can assign different roles to different accounts to ensure each account has only the permissions it needs to support your app. For details see, Setting Up Access Control.

App Engine firewall

The App Engine firewall enables you to control access to your App Engine app through a set of rules that can either allow or deny requests from the specified ranges of IP addresses. You are not billed for traffic or bandwidth that is blocked by the firewall. Create a firewall to:

Allow only traffic from within a specific network

Ensure that only a certain range of IP addresses from specific networks can access your app. For example, create rules to allow only the range of IP addresses from within your company's private network during your app's testing phase. You can then create and modify your firewall rules to control the scope of access throughout your release process, allowing only certain organizations, either within your company or externally, to access your app as it makes its way to public availability.

Allow only traffic from a specific service

Ensure that all the traffic to your App Engine app is first proxied through a specific service. For example, if you use a third-party Web Application Firewall (WAF) to proxy requests directed at your app, you can create firewall rules to deny all requests except those that are forwarded from your WAF.

Block abusive IP addresses

While Google Cloud has many mechanisms in place to prevent attacks, you can use the App Engine firewall to block traffic to your app from IP addresses that present malicious intent or shield your app from denial of service attacks and similar forms of abuse. You can add IP addresses or subnetworks to a denylist, so that requests routed from those addresses and subnetworks are denied before they reach your App Engine app.

For details about creating rules and configuring your firewall, see Controlling App Access with Firewalls.

Ingress controls

You can use Ingress controls to restrict inbound traffic to your App Engine app. By default, your App Engine app accepts traffic from all network origins. To modify the default settings, and edit and view the available settings, see Specify ingress settings.

Egress controls

Egress controls determine which outbound traffic from your App Engine service routes through your Virtual Private Cloud (VPC) network when you use Direct VPC egress (Preview) or a Serverless VPC Access connector. By default, only requests to private IP addresses route through your VPC network, while requests to public destinations route directly to the internet. With egress control settings, you can route all outbound traffic (all-traffic) from your App Engine service through your VPC network. To configure egress settings for your app, see Egress settings.

Shared internet egress risks and acceptable use

By default, outbound traffic to the public internet uses a regional pool of dynamic IP addresses shared with other serverless workloads. Keep the following risks and responsibilities in mind:

• Noisy or abusive traffic from another workload in the region can degrade the reputation of the shared IP address pool. External firewalls and third-party web application firewalls (WAFs) might throttle or block requests from these shared IP addresses, causing connection timeouts or HTTP 403 errors.
• Don't use the default shared IP pool for reputation-sensitive external endpoints, such as payment gateways, hosted databases, or partner APIs behind WAFs. Instead, route all outbound traffic (all-traffic) through your VPC network and use Cloud NAT with dedicated static outbound IP addresses.
• Don't run network scanning, port enumeration, host fingerprinting, vulnerability probing, web scraping, or load testing over the default shared internet egress path. This activity degrades shared IP reputation, can disrupt service for other customers in violation of the Google Cloud Acceptable Use Policy, and might cause Google to throttle or suspend your workload.

• If you run authorized security scanning, host fingerprinting, or load testing workloads, you must isolate your outbound traffic. Route all outbound requests (all-traffic) through your VPC network and Cloud NAT using your own static outbound IP addresses.

Security scanner

The Google Cloud Web Security Scanner discovers vulnerabilities by crawling your App Engine app, following all that links within the scope of your starting URLs, and attempting to exercise as many user inputs and event handlers as possible.

In order to use the security scanner, you must be an owner of the Google Cloud project. For more information on assigning roles, see Setting Up Access Control.

You can run security scans from the Google Cloud console to identify security vulnerabilities in your App Engine app. For details about running the Security Scanner, see the Using Web Security Scanner.

VPC Service Controls

Not supported in the App Engine standard environment.