Anti Scraping Techniques 101
Table of Contents
Businesses have many reasons why they compile large amounts of data, such as collecting email addresses, assessing the competition, or monitoring social media. Web scraping is one of the most effective ways to do so. Broadly speaking, web scraping is the process of obtaining information from a webpage by writing a code (bot) that can extract the information automatically, without manual intervention. It is important to grasp that web data collection is a widely used practice.
Generally speaking, websites do not provide open access to their data, thus making it necessary to scrape their content if a direct Application Programming Interface (API) is unavailable. An API would make data extraction more efficient and effective, even among websites that actually offer data such as government statistics and survey agencies. Often the only way to do so is via downloading batches of information in CSV or XLS formats — spreadsheets of data manipulated and grouped by some sort of interface prior to download. Even if an API is present, it may be of poor design and not provide all the necessary data.
Lastly, often one or two sources are not enough. Businesses may need to go through multiple websites to get what they need, because even information aggregators that package relevant market, industry, sector, vertical, or geographical information together may not provide sufficient information for an organization’s purposes. Ergo, web scraping.
So, what is anti-scraping?
Websites use anti-scraping or bot measures to protect their data, content, and services from automated data extraction. By and large, this is done to ensure that their content is only accessed and used by legitimate users and not by malicious actors who may be trying to misuse the information. Anti-scraping measures help to protect websites from data theft, spam, and other malicious activities. One typical example of this is that professional websites may want to put anti-email scraping measures in place to avoid bots from easily obtaining company emails for spamming and phishing attempts.
Malefactors can take advantage of websites that have no anti-bot measures in place with more sophisticated approaches as well, such as by launching distributed denial-of-service (DDoS) attacks. These attacks are designed to overwhelm websites with a massive amount of traffic, resulting in the website becoming unavailable to legitimate users. Additionally, malicious actors can use DDoS attacks to spread malicious code within company networks, which can lead to data theft and other malicious activities. Anti-scraping software and other measures constantly monitor company networks to prevent such wide-scale attacks from ever becoming a reality.
Additionally, data is the most important asset in the world today. Businesses understand this. That is why they take precautions to shield their information — most of the time. Some of it is available on the web for everyone to see, however, they don’t want it to be so accessible as to easily let other companies take it effortlessly via scraping. That is why more and more websites are putting anti-scraping techniques in place to prevent this.
So, now we’re presented with an intriguing impasse: as scraping services and solutions become more prevalent, so do web scraping anti-scrape measures.
What constitutes anti-web scraping services and protections?
Due to demand from Big Data and AI, there is an increasing need to scrape data; anti-scraping measures, on the other hand, are trying to keep up with increasingly growing, more sophisticated, and better coordinated malicious attacks.
Anti-scraping countermeasures today are generally based on two prominent aspects:
- Analyzing the digital footprint left behind: When browsing the web, you produce what can be thought of as a digital footprint. This consists of details such as browser cookies, your IP address, browser settings and plugins, and more. This helps to differentiate between individuals carrying out activities or automated programs scraping websites.
- Utilizing machine learning and statistics: Machine learning and advanced statistical analysis are used to formulate sophisticated anti-scraping solutions that analyze data from the web (Big Data) to detect behavior patterns consistent with bot-like activity.
There are more nuanced and advanced factors, but these two are the major ones legitimate web scraping users typically need to worry about during their routines.
Essentially, your web scraping needs to either emulate or actually bear the right digital footprints. So, aggressive website protection measures do not flag your bots as malicious (as they would, say, bots attempting to take advantage of vulnerabilities to launch DDoS attacks). Even if a website uses machine learning to more accurately identify humans from bots, there are still backdoors or other methods to avoid triggering defenses and therefore bypass anti-scraping measures.
Prominent anti-scraping measures to know
For organizations that regularly engage in web scraping, anti-scrape measures can easily become hurdles to their automated research — especially if they hit roadblocks across many of the websites they scrape. It would be helpful to understand the most prominent anti-scraping techniques in use today.
IP address policing
A straightforward anti-scraping approach is to restrict requests coming from a particular IP address or group. In essence, the website monitors all incoming requests, and if too many come from the same source, it will block that IP address or group of addresses.
A website may also block an IP address if it detects multiple requests in a short span of time. This is a common defense against automated web scraping or “bot” activity. To protect itself, the site can mark any requests from that IP as generated by bots.
Anti-scraping and anti-bot systems can tag your IP address permanently. There are online tools to determine if yours has been affected. To stay safe, don’t use flagged IP addresses when scraping the web.
If you want to keep scraping without being blocked, introducing random pauses between requests or using an IP rotation system with a premium proxy service is the way to go.
User Agent and/or Other HTTP Headers
A website can detect malicious requests and guard against them by using HTTP headers. It monitors the most recent incoming requests, blocking any that don’t have an approved set of values in certain header fields. Anti-scraping techniques such as this are similar to IP banning.
An important header to be aware of when web scraping is the User-Agent. This string identifies what application, OS, and version of the HTTP request is coming from. It’s essential that your crawlers use a valid User-Agent for successful scraping.
Web scrapers using requests that don’t contain a Referrer header may also be blocked. This HTTP header contains an address (absolute or partial) of the web page from which the request originated.
Logins or authentication walls
If you’re looking to access data from sites like LinkedIn or Instagram, there’s a good chance you’ll find it behind an authentication wall. That goes for social media platforms, too. Most social platforms require users to be logged in before they can see any of the content. So if you want your hands on that info, having proper authorization is essential.
To authenticate a request, the server looks at its HTTP headers. Specifically, some cookies contain values to be sent as authentication headers. If you don’t know what that means, an HTTP cookie is just a small piece of data stored in the browser’s memory. The browser creates login cookies when it gets a response from the server after logging in.
To gain access to a website protected by a login page, you’ll need the right cookies. These values get transmitted through HTTP headers in the request when you log in. To see them, use your browser’s DevTools.
You can use a headless browser to simulate the login process, navigate around it, and can add complexity to your web scraping.
Using honeypot tactics
A honeypot is a decoy system built to appear legitimate but with some security flaws. These systems divert malicious users and bots from primary targets, while also enabling protection systems to see how attackers behave. A honeypot could be a false website that does not have any anti-scraping protections in place, providing incorrect or false data as well as collecting all requests for training purposes.
The best way to dodge the honeypot trap is by verifying that the content on the site you are scraping is real. Another option would be using a proxy server to hide your IP address from being seen by the target website. This renders any efforts of tracing it futile.
As a final note, when crawling a website, be sure to avoid following any hidden links. These are usually marked with the “display: none” or “visibility: hidden” CSS rules and can lead to honeypot pages.
On the other hand, the famous CAPTCHA (Completely Automated Public Turing test to tell Computers and Humans Apart) is a challenge-response system that requires users to provide a solution that only humans can solve — like selecting images of a certain subject or object. CAPTCHAs have become the go-to method of anti-bot protection since many Cloud Delivery Network services now contain them as part of their default security measures. By preventing automated systems from being able to browse an online site, it stops scrapers from scouring the material on it too.
Changing HTML code or web formats
BeautifulSoup is one of many scrapers that use HTML tags and pre-defined properties such as selectors like XPath and CSS when parsing data. But some websites actively look to hinder scraping via tools like these by modifying the HTML class names or other properties on a regular basis, making it difficult for automated systems to keep up. If this happens, the web scraper needs intervention from its user in order for them to successfully acquire their desired information.
Converting text into other formats is also an effective way to combat many approaches to web scraping. Websites may use various formats such as PDFs, images, or videos to deliver content. Yet this approach isn’t without drawbacks — format conversion tends to slow down loading times for website users.
Using anti-web scraping services
Most anti-scraping services provide not only scraper-blocking solutions but analysis tools as well. It might be beneficial to review these in order to understand what scrapers are up against. Knowing the full range of anti-scraping measures available is particularly helpful when choosing a suitable one for your particular needs.
Effective Proxy Server Use Web Scraping
For many of these anti-scraping measures, using proxy servers and advanced features such as proxy rotation are effective circumvention methods.
Proxies can be incredibly useful when web scraping, as they act as intermediaries between your computer and the internet. When you send a query to a website, the proxy will receive it before forwarding it. It then returns the response back to you.
Websites go to great lengths to protect themselves against scrapers, mostly to prevent server overloads and avoid becoming targets for malicious attacks. So, if you want reliable scraping results, make sure your proxies come from providers who offer extra features such as proxy rotation. Proxy rotation is the process of switching between different IP addresses to avoid detection and access restrictions.
Proxy rotation is made even more effective when used in conjunction with rate limiting. Rate limiting essentially delays requests sent to websites so that not too many are sent consecutively, triggering defense mechanisms. Rate limiting is a good way to avoid detection and ensure that your scraping activities don’t overload the server as they camouflage bots better, making websites think they’re humans based on their waiting behavior when accessing data. Essentially, proper proxy use along with other features such as delaying requests can help avoid triggering website defenses monitored fingerprinting.
Fingerprinting is a method used by websites to recognize when a particular user is trying to access the site repeatedly from different IP addresses within a short period of time. This helps identify malicious actors and can help prevent them from attempting data theft or other malicious activities. Fingerprinting works by creating an “identity profile” based on the characteristics of each request made, such as the type and version of the web browser being used, language preferences, operating system details, and plug-ins installed in their browsers. This then allows websites to recognize whether it’s coming from a legitimate user or not.
A website scraper can be categorized as non-malicious by fingerprinting technology if it adheres to certain parameters and guidelines. For example, the scraper must use a web browser that is commonly used for legitimate purposes such as Chrome or Firefox, and not something like Tor Browser. Further, the user’s language preferences should match those of the website’s location. Most of these can be configured in web scraping by changing values in request headers or other settings.
Ethical proxy use
Rayobyte is the go-to proxy provider for web scraping. We have residential proxies, ISP (Internet Service Provider) proxies, and data center proxies to fit your needs. Our team is highly professional and ethical. So, you can trust us with all your projects.
If you’re looking to scrape the web, residential proxies are your best bet. Our team ensures that we only source top-notch IP addresses provided by ISPs, and strive for minimal downtime.
Datacenter proxies are a great way to increase speed when it comes to web scraping. By routing traffic through data centers, they can get your data where you need it quickly and cost-effectively — even though the number of unique, nonresidential IP addresses may be reduced.
Lastly, using an ISP proxy gives you the best of both worlds — the speed of a data center connection and the trustworthiness associated with an internet service provider.
Finding the most appropriate web scraping strategy is vital if you want to access valuable data from diverse sources. It’s important to find a method that works for you and build the necessary framework (in the form of proxy servers) to make it happen.
When you find your ideal setup, make sure it is supported by a reliable proxy server provider like Rayobyte to circumvent anti-scraping measures. We provide top-notch proxies plus Scraping Robot to automate parts of your web scraping process. Check out our solutions today!
The information contained within this article, including information posted by official staff, guest-submitted material, message board postings, or other third-party material is presented solely for the purposes of education and furtherance of the knowledge of the reader. All trademarks used in this publication are hereby acknowledged as the property of their respective owners.
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