browser-fingerprinting

Avoiding bot detection: How to scrape the web without getting blocked? 👨‍🔧

Whether you're just starting to build a web scraper from scratch and wondering what you're doing wrong because your solution isn't working, or you've already been working with crawlers for a while and are stuck on a page that gives you an error saying you're a bot, you can't go any further, keep reading.

Anti-bot solutions have evolved in recent years. More and more websites are introducing security measures: from simple ones, such as filtering IP addresses according to their geolocation, to advanced ones based on in-depth analysis of browser parameters and behavioral analysis. All this makes web scraping content more difficult and costly than a few years ago. Nevertheless, it is still possible. Here I highlight a few tips that you may find helpful.

Where to begin building undetectable bot?

Below you can find list of curated services that I used to get around different anti-bot protections. Depending on your use-case you may need one of the following:

Once you have decided on what type of evasion is going to be needed in your project, you can use the list below to pick the best provider for your project:

Helpful services

List of anti-bot software providers

This is a non-exhaustive list of companies that provide the most advanced anti-bot solutions for businesses ranging from smaller e-commerce sites to Fortune 500 companies:

• Akamai Bot Manager by Akamai
• Advanced Bot Protection by Imperva (former Distil Networks)
• DataDome Bot Protection
• PerimeterX (acquired by HUMAN)
• Shape Security (acquired by F5)
• Cloudflare Bot Management
• Barracuda Advanced Bot Protection
• HUMAN
• Kasada
• Alibaba Cloud Anti-Bot Service
• Travatar
• Ocule
• Sift
• Forter
• Reblaze
• Arkose Labs
• LexisNexis® ThreatMetrix®

How do you know who is getting you blocked?

Join extra.community. There runs an automated tester Botty McBotface that uses several complicated techniques to determine what exact protection a tested website uses (credits to berstend and others from #insiders).

Available stealth browsers with automation features

Important You use this software at your own risk. Some of them contain malwares just fyi. Use with caution.

Legend: 🤮 - Evasion based on noise. ❌ - No. ✔️ - Acceptable (with support libraries or not). 👍 - Very nice.

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A ⭐ on this repo will be appreciated!

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Technical insights into bypassing bot detection

Here I study various aspects of evasion techniques used to get around bot detection systems used by major online websites. I cover both technical and non-technical matters, including recommendations, references to scientific papers and more.

The technical findings that I am sharing below are based on observations of running web scraping scripts for a few months against websites protected by the major anti-bot solution vendors.

I constantly add stuff to this section. Over time I will try to make it look&feel more structured.

Random, maybe useful

• Cap FPS for Chromium with software rendering --use-gl=swiftshader - Limit CPU usage from SwiftShader by redraw freq. of Chromium in AVD
• Unlike some public comments on that matter chrome devtools protocol actually works on AVD-s with puppeteer
• Abusing GPU cache to create persistent tracking identifiers
• Data WhiteOps (now HUMAN) collects (2020)

puppeteer-extra-plugin-stealth 😈

✔️ Win / ❌ Fail / 🤷 Tie :

• ✔️ Client Hints - Shipped recently. In line with Chromium cpp implementation.
• ✔️ General navigator and window properties
• ✔️ Chrome plugins and native extensions - This includes both Widevine DRM extension, as well as Google Hangouts, safe-browsing etc.
• 🤷 p0f - detect host OS from TCP struct - Not possible to fix via Puppeteer APIs. Used in Akamai Bot Manager to match against JS and browser headers (Client Hints and User-Agent). There is a detailed explaination of the issue. The most reliable evasion seems to be not spoofing host OS at all, or using OSfooler-ng.
• 🤷 Browser dimensions - Although stealth plugin provides window.outerdimensions evasion, it won't work without correct config on non-default OS in headless mode; almost always fails when viewport size >= screen resolution (low screen resolution display on the host).
• ❌ core-estimator - This can detect mismatch between navigator.hardwareConcurrency and SW/WW execution profile. Not possible to limit/bump the ServiceWorker/WebWorker thread limit via existng Puppeteer APIs.
• ❌ WebGL extensions profiling - desc. tbd
• ❌ RTCPeerConnection when behind a proxy - Applies to both SOCKS and HTTP(S) proxies.
• ❌ Performance.now - desc. tbd (red pill)
• ❌ WebGL profiling - desc. tbd
• ❌ Behavior Detection - desc. tbd (events, params, ML+AI buzz)
• ❌ Font fingerprinting - desc. tbd (list+version+renderer via HTML&canvas)
• ❌ Network Latency - desc. tbd (integrity check: proxy det., JS networkinfo, dns resolv profiling&timing)
• ❌ Battery API - desc. tbd
• ❌ Gyroscope and other (mostly mobile) device sensors - desc. tbd

Stealth alternatives 🩹

Where puppeteer-extra-plugin-stealth falls short, there are attempts to go deeper and patch at lower levels. Runtime.Enable events, navigator.webdriver, and other attributes can't be reliably masked for JS in JS (Object.defineProperty). Below are some projects patching at either the automation library level, the CDP transport, or the browser binary itself:

Multilogin, Kameleo and others 💰🤠

• ❌ General navigator and window properties - As per Multilogin documentation custom browser builds typically lag behind the latest additions added by browser vendors. In this case modified Chromium M7X is used (almost 10 versions behind when writing this).
• 🤷 Font masking - Font fingerprinting still leaks host OS due to use of different font rendering backends on Win/Lin/Mac. However, the basic "font whitelisting" technique can help to slightly rotate browser fingerprint.
• ❌ Inconsistencies - Profile misconfiguration leads to early property/behavior inconsitency detection.
• ❌ Native extensions - Unlike puppeteer-extra-plugin-stealth custom Chromium builds such as ML and Kameleo provide at most an override for native plugins and extensions shipped with Google Chrome.
• ❌ AudioContext APIs and WebGL property override - Manipulation of original canvas and audio waveform can be detected with custom JS.
• ✔️ Audio and GL noise

tbd (if you have an active subscription in any of these services and don't mind sharing an account drop me an email ❤️)

Fingerprint test pages

These websites may be useful to test fingerprinting techniques against a web scraping software

Non-technical notes

I need to make a general remark to people who are evaluating (and/or) planning to introduce anti-bot software on their websites. Anti-bot software is nonsense. Its snake oil sold to people without technical knowledge for heavy bucks.

Blocking bot traffic is based on the premise that you (or your technology provider) can distinguish bots from real users. To make this happen various privacy-invasive techniques are applied. To date none of them has been proved to be successful against specialized web scraping tools. Anti-bot software is all about reducing cheap bot traffic. It makes the process of scraping more expensive and complicated, but does not make it entirely impossible.

Anti-bot software vendors use detection techniques that fall into one of these two categories:

Binary detection

No specialized web scraping software is used. Vendor can detect the bad traffic based on information openly disclosed by the scraper e.g. User-Agent header, connection parameters etc.

As a result only bots that are not targeted to scrape specific website are blocked. This will make most of the managers happy, because the overall number of bad traffic goes down and it may almost look like there is no more bot traffic on the website. Wrong.

Traffic clustering

More advanced web scrapers make use of residential proxies and implement complex evasion techniques to fool anti-bot software to think that the web scraper is a real user. No detection mechanism exists to get around this due to technical limitation of web browsers.

In this case, most of the time the vendor will be only able to cluster the bad traffic by finding patterns in bot traffic and behavior. This is where browser fingerprinting comes into play. The problem with banning the traffic here is that it may turn out to be a risky operation when bots are successfully mimicking real users. There is a chance that by blocking bots the website will become unavailable to real visitors.

Gateways, captchas & co

If you think this is a way to go google "captcha resolve api".

Support

If you have problems with scraping specific website, write me a short email at [email protected] — happy to chat 😊.

Have I mentioned a ⭐ would be appreciated? :-)

➡️ Ethereum address 0x380a4b41fB5e0e1EB8c616eBD56f62f8F934Bab6