Bot Protection
WAAS bot protection provides visibility into bots and other automation frameworks accessing protected web applications and APIs.
Bot Categories
WAAS detects known good bots as well as other bots, headless browsers and automation frameworks. WAAS is also able to fend off cookie-dropping clients and other primitive clients by mandating the use of cookies and javascript in order for the client to reach the protected origin.
Bots are categorized into the following Categories:
- Search Engine Crawlers- Bots systematically crawling and indexing the world wide web to index pages for online searching. Also known as spider bots or web crawlers.
- Business Analytics Bots- Bots that crawl, extract and index business related information.
- Educational Bots- Bots that crawl, extract and index information for educational purposes, such as academic search engines.
- News Bots- Bots that crawl, extract and index the latest news articles, usually for news aggregation services.
- Financial Bots- Bots that crawl, extract and index financial related data.
- Content Feed Clients- Automated tools, services or end-user clients that fetch web contents for feed readers.
- Archiving Bots- Bots that crawl, extract and archive web site information.
- Career Search Bots- Automated tools or online services that extract and index job related postings.
- Media Search Bots- Bots that crawl, extract and index media contents for search engine purposes.
This category contains various bots and other automation frameworks which cannot be classified by their activity or origin
- Generic Bots- Clients with attributes that indicate an automated bot.
- Web Automation Tools- Scriptable headless web browsers and similar web automation tools.
- Web Scrapers- Automated tools or services that scrape web site contents.
- API Libraries- Software code libraries for Web API communications.
- HTTP Libraries- Software code libraries for HTTP transactions.
- Request Anomalies- HTTP requests with anomalies that are not expected from common web browsers.
- Bot Impersonators- Bots and automation tools impersonating as known good bots to evade rate limitation and other restrictions.
- Browser Impersonators- Automated tools or services that impersonate common web browser software.
Users can create custom signatures to be used based on HTTP headers and source IPs.
User-defined signatures are useful for tracking customer specific bots, self-developed automation clients and traffic that appears suspicious.
Detection methods
WAAS uses static and active methods for detecting bots.
Static detection examines each incoming HTTP request and analyzes it to determine whether it was sent by a bot.
Active detections make use of javascript and Prisma Sessions Cookies to detect and classify bots.
Prisma Session Cookies set by WAAS are encrypted and signed to prevent cookie tampering. In addition, cookies include advanced protections against cookie replay attacks where cookies are harvested and re-used in other clients.
Prisma sessions are intended to address the problem of "Cookie Droppers" by validating clients support of cookies and Javascript before allowing them to reach the origin server. Once enabled, WAAS serves an interstitial page for any request that does not include a valid Prisma Session Cookie. The interstitial page sets a cookie and redirects the client to the requested page using Javascript. A client that doesn’t support cookies and Javascript will keep receiving the interstitial page. Browsers can easily proceed to the requested page, and once they possess a valid cookie they will not encounter the interstitial page.
When enabled, javascript will be injected periodically in server responses to collect browser attributes and flag anomalies typical to various bot frameworks. Javascript fingerprint results are received and processed asynchronously and are used to classify session for future requests.
Detection workflow
Deploying Bot Protection
Known bots
Unknown bots
- Click on Bot protection tab.
- Click on Unknown Bots.
- Choose actions for each bot category.
- If Request anomalies are enabled, choose sensitivity threshold
- Strict enforcement- high sensitivity (a few anomalies suffice for classifying as bot).
- Moderate enforcement- medium sensitivity.
- Lax enforcement- low sensitivity.
User-defined bots
- Click on Bot protection tab.
- Click on User-defined bots.
- Click on Define new bot button.
- Create bot signature by using a combination of the following fields:
- HTTP Header name- specify HTTP header name to include in the signature
- Header Values- comma separated list of values to be matched on in the HTTP header. Wildcard is allowed.
- Inbound IP sources- specify Network list of IP addresses from which the bot originates.
- Choose an action to apply.
Enabling active detections
- Click on Bot protection tab.
- Click on Active bot detections.
Active Bot detection requires Prisma Sessions Cookies to be enabled in the advanced settings tab.
- Choose actions to apply.
- Session Validation- action to apply when WAAS is unable to validate the session, either due to cookie tampering or cookie replay.
- Javascript-based detection- enable periodic injection of javascript to collect browser attributes and flag anomalies typical to various bot frameworks.
- Javascript injection timeout- once javascript is enabled, choose action to apply when the browser does not send a response to the javascript injection in a timely manner.
Bot protection events
- Known bots- if a known bot is detected, the event message and attack type will provide details regarding the bot classification.
- Unknown bots- if an unknown bot is detected, the event message and attack type would provide details regarding the bot classification
- User-defined bots- a used-defined bot has been detected.
- Session Validation- The web client failed to pass the bot-detection session validation checks (e.g. prisma session cookie has been tampered with etc.).
- Javascript Injection Timeout- the web client failed to pass the bot-detection JavaScript injection check in reasonable time (timeout).
- Missing Cookie- client made a non GET request without a cookie.
Bot Protection Actions
Requests that trigger a WAAS bot protection are subject to one of the following actions:
- Alert- The request is passed to the protected application and an audit is generated for visibility.
- Prevent- The request is denied from reaching the protected application, an audit is generated and WAAS responds with an HTML page indicating the request was blocked.
- Ban- Can be applied on either IP or Prisma Session IDs. 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.
- Allow (available for user-defined bots)- request is forwarded to the protected application and no audit is generated.
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.
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.