1. Overview

WAAS is able to enforce rate limit on IPs or sessions to protect against high-rate and "low and slow" application layer DoS attacks.

waas dos protection

2. DoS protection Overview

WAAS is able to limit the rate of requests to the protected endpoints within each app based on two configurable request rates:

  • Burst Rate - Average rate of requests per second calculated over a 5 seconds period

  • Avarage Rate - Average rate of requests per second calculated over a 120 seconds period

Users are able to specify match conditions for qualifying requests to be included in the count. Match conditions are based on HTTP methods, File Extensions and HTTP response codes.

Users are also able to specify Network lists to be excluded from the DoS protection rate accounting.

If no match conditions are specified - all requests to the protected endpoints would be included in the rate accounting.

3. Enabling DoS protection

  1. Enter DoS Protection tab and set the DoS Protection toggle to On

    waas dos protection toggle
  2. Set the effect with the action to apply once a threshold is reached.

    waas dos action
    A message at the top of the page indicates the entity by which the ban will be applied (IP or Prisma Session ID).
    To enable ban by Prisma Session ID, Prisma Session Cookies has to be enabled in the Advanced Settings tab. for more information please refer to the Advanced Settings help page.
  3. Apply rate limitation thresholds (requests per second) for Burst rate (calculated over 5 seconds) and for Average rate (calculated over 120 seconds)

  4. To apply the rate limitation on a subset of requests click on waas dos add match conditions button.

    waas dos new condition

    Conditions can be specified as a combination (AND) of the following:

    • HTTP Methods

    • File Extensions - multiple extensions are allowed (e.g. .jpg, .jpeg, .png).

    • HTTP Response Codes - specify either a single response code, a range or a combination of them (e.g. 302, 400-410, 500-599).

  5. Multiple match conditions are allowed (OR relation between them).

    waas dos multi

    In the above example the following request would be counted against the rate limitation thresholds:

    • HEAD HTTP requests

    • POST HTTP requests with file extension of .tar.gz

    • GET or PUT HTTP requests with file extension of .jpg, .jpeg, .png to which the origin responded with and HTTP response code of 302 or in the range of 400-410 or in the range of 500-599

  6. Specify Network lists of IP addresses to be excluded from the rate accounting.

    waas dos excluded

4. DoS actions

Requests that exceed the rate limitation thresholds are subject to one of the following actions:

  • Alert - The request is passed to the protected application and an audit is generated for visibility.

  • Ban - Can be applied on either IP or Prisma Session. All requests originating from the same IP/Prisma Session to the protected application are denied for the configured time period (default is 5 minutes) following the last detected attack.

For more information on enabling Prisma Sessions and configuring ban definitions please refer to the Advanced Settings help page.
There is a message at top of the App firewall page showing the current setting for ban.
WAAS implements state, which is required for banning user sessions by IP address or Prisma Sessions. Because Defenders do not share state, any application that is replicated across multiple nodes must enable IP stickiness on the load balancer.