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Working with custom signals

Custom signals are labels that describe request properties that you find important to track. The conditions for attaching a custom signal to a request are defined by request rules that use the Add signal action. When paired with a request rule, custom signals can help increase visibility into:

  • what is being attacked. Tag requests with specific paths (e.g., /admin or /api) to understand where bad actors are attempting to exploit your application.
  • where attacks originated. Tag requests based on their source, such as specific regions, countries, or Autonomous System Numbers (ASNs). You can then create additional rules based on this information. For example, you could create a rule to block all requests from specific countries and Tor networks.
  • known actors. Tag requests from known actors. You can then apply a positive security posture and allow traffic from the trusted sources (e.g., known vendors, Let's Encrypt, mobile data site verification, and penetration testers on internal security teams).
  • what happens after requests are allowed. Tag allowed requests that exhibit notable response behaviors (e.g., a 404 HTTP response code or a no JSON results error). This additional information can better highlight attack patterns, especially when seen with or without attack signals.

The Requests page lists a representative sample of requests that have been tagged with custom signals.

Limitations and considerations

When working with signals, keep the following things in mind:

  • Custom signals are not included with the Essential platform.
  • Account (also known as corp) signals can only be created, edited, and deleted by owners (superusers).
  • Signals are limited to 200 per account (corp) plus 200 per workspace (also known as site).

Creating custom signals

Custom signals can be created at the account (corp) or workspace (site) level. Account (corp) signals can be used in rules on every workspace (site). Workspace (site) signals can only be used in rules for one workspace (site).

Creating signals used by all workspaces (sites)

Account-level (corp-level) signals can be used in rules on every workspace (site) in your account. To create an account-level (corp-level) signal, complete the following steps:

  1. Fastly control panel
  2. Next-Gen WAF control panel
  1. Log in to the Fastly control panel.
  2. Go to Security > Next-Gen WAF > Signals.
  3. From the workspaces bar, click the menu Menu icon to the right of the workspace name and select your account name.

  4. Click Add account signal.

    The Add account signal form completed for the `blocked-countries` custom signal

  5. In the Signal name field, enter the name of the custom signal.

  6. (Optional) In the Description (optional) field, enter a description for the custom signal.

  7. Click Create custom signal.

  8. (Optional) Create a request rule that uses the Add signal action to define when the WAF should tag requests with the new signal. If you do not create a rule, the signal will never be used.

Creating signals used by one workspace (site)

Site-level (workspace-level) signals can only be used in rules for one workspace (site). To create a site-level (workspace-level) signal, complete the following steps:

  1. Fastly control panel
  2. Next-Gen WAF control panel

To create a custom signal, complete the following steps:

  1. Log in to the Fastly control panel.
  2. Go to Security > Next-Gen WAF > Signals.
  3. From the workspaces bar, click the menu Menu icon to the right of the workspace name and select a workspace.

  4. Select the Custom tab.

  5. Click Add custom signal.

    The Create custom signal form completed for the `blocked-countries` custom signal

  6. In the Signal name field, enter the name of the custom signal.

  7. (Optional) In the Description (optional) field, enter a description for the custom signal.

  8. Click Create custom signal.

  9. (Optional) Create a request rule that uses the Add signal action to define when the WAF should tag requests with the new signal. If you do not create a rule, the signal will never be used.

Updating signals

You can update a custom signal to revise the description of the signal.

Updating signals used by all workspaces (sites)

To update the description of a signal that applies to all workspaces (sites), complete the following steps:

  1. Fastly control panel
  2. Next-Gen WAF control panel
  1. Log in to the Fastly control panel.
  2. Go to Security > Next-Gen WAF > Signals.
  3. From the workspaces bar, click the menu Menu icon to the right of the workspace name and select your account name.

  4. Click the pencil Pencil icon to the right of the custom signal you want to edit.

    The Edit account signal form completed for the `blocked-countries` custom signal

  5. In the Description (optional) field, enter a description for the custom signal.

  6. Click Update custom signal.

Updating signals used by one workspace (site)

To update the description of a signal that applies to a specific workspace (site), complete the following steps:

  1. Fastly control panel
  2. Next-Gen WAF control panel
  1. Log in to the Fastly control panel.
  2. Go to Security > Next-Gen WAF > Signals.
  3. From the workspaces bar, click the menu Menu icon to the right of the workspace name and select a workspace.

  4. Click Custom.

  5. Click the pencil Pencil icon to the right of the custom signal that you want to modify.

    The Edit custom signal form completed for the `blocked-countries` custom signal

  6. In the Description (optional) field, enter a description for the custom signal.

  7. Click Update custom signal.

Deleting custom signals

To delete a signal, follow the steps described below.

Deleting signals used by all workspaces (sites)

  1. Fastly control panel
  2. Next-Gen WAF control panel
  1. Log in to the Fastly control panel.
  2. Go to Security > Next-Gen WAF > Signals.
  3. From the workspaces bar, click the menu Menu icon to the right of the workspace name and select your account name.
  4. Click the more menu More icon to the right of the custom signal you want to delete and then Delete custom signal.
  5. Click Delete custom signal.

Deleting signals used by one workspace (site)

  1. Fastly control panel
  2. Next-Gen WAF control panel

To delete a custom signal, complete the following steps:

  1. Log in to the Fastly control panel.
  2. Go to Security > Next-Gen WAF > Signals.
  3. From the workspaces bar, click the menu Menu icon to the right of the workspace name and select a workspace.
  4. Click Custom.
  5. Click the more menu More icon to the right of the custom signal you want to delete and then Delete custom signal.
  6. Click Delete custom signal.

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