How to Use cURL to Ignore an SSL Certificate

SSL certificates are an important part of internet security. They help users navigate the internet with some level of security protection from those who seek to steal sensitive information. Yet, it is not always a good thing, and in some situations, you may want to find a way to get around it. You can use cURL to ignore SSL in some cases, and it could be easier to do this than you realize.

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You can use cURL to ignore SSL errors and get around problems. However, you will need to complete several steps to learn how to bypass SSL with cURL.

What Is SSL and cURL?

Secure Sockets Layer (SSL) is a protocol for securing communication over a computer network. Transport Layer Security (TLS) is the successor of SSL and is also commonly used. SSL secures the transfer of data. There are three significant reasons why SSL and TLS certificates are in place:

1. They create encryption: They encrypt the data transmitted from the client to the server, which directly ensures that any sensitive information is being transferred in a safe and secure manner.
2. They support authentication: Another reason SSL and TLS certificates are so important is the authentication they offer. The certificate identifies the server to the client, confirming that the server is who it claims to be, helping to reduce the risk of connecting to fraudulent or other malicious sites.
3. Data integrity is protected: These certificates ultimately ensure the data that is being sent and received is in its original form and has not been altered or tampered with in any way during the process.

These certificates are typically issued by Certificate Authorities, sometimes called CAs. They are considered trusted entities that will validate the identity of the website and, only upon doing so, issue a certificate to confirm the site is legitimate.

Now, consider how cURL works. It is a command line tool and library. It works to transfer data with URLs. It can be used with various protocols, including HTTP, HTTPS, and others. Noting how it works, you can see that cURL is used to transfer data, and SSLs secure that transfer. In that way, cURL performs SSL certificate validation (verifying the security prior to transferring data over the internet from one site to another).

There are some situations where you may need to disable SSL. In most situations, SSL is a good thing. It provides a better level of internet security protection, and it may be one of the foremost resources for using the internet safely. However, there are some situations where it can get in the way, making it harder or impossible to complete various tasks.

For example, in the development process, it is nearly always necessary to use a self-signed certificate or at least develop and build in an environment where SSL certificates are not in place (and they may not be configured yet for some time). Additionally, legacy systems and our APIs that use outdated SSL certificates can be a core reason why we want to use cURL to ignore SSL. It provides a way for you to work around the otherwise prominent block.

Also, note that bypassing SSL has a huge benefit for debugging processes. It can help you to diagnose and even repair problems related to those certificates.

Considering this, if you still want to use cURL to ignore the SSL cert, we have to provide you with a warning (all tasks like this need a warning!)

Even if you are just in development and believe you have a protected environment, there are risks in using sites without an SSL certificate. Note that, with the increase in the number of attacks today, it is critical to be very careful of the environment before you actually use the cURL SSL certificate and ignore the strategies listed here. The biggest risks come in the form of man-in-the-middle attacks, data breaches, and, in some situations, losing user trust. These are risks to anyone who accesses a site with an SSL certificate, and therefore, we only encourage you to use cURL to ignore SSL when in a development or production environment.

How to Use cURL to Ignore SSL

For those who want a simple process., it helps to understand what happens when the cURL does not ignore certificates. Typically, if you send a cURL request to a website and that site has an ineffective or otherwise invalid SSL certificate, you will get an error message. It is likely to read like this:

curl https://expired.websitename.com/

curl: (60) SSL certificate problem: certificate has expired

More details here: https://curl.se/docs/sslcerts.html

curl failed to verify the legitimacy of the server and therefore could not

establish a secure connection to it. To learn more about this situation and

how to fix it, please visit the web page mentioned above.

That is to be expected. Now, you can use the -k command to ignore SSL in cURL. This is the most straightforward way to use cURL to skip SSL. To ignore SSL certificate errors, pass the -k cURL command.

To do that, use the following command:

curl -k https://expired.website.com/

That is the most simplistic of strategies, and it works in most situations. You can also use the – – insecure command by applying this code:

curl –insecure https://expired.website.com/

In these examples, replace “website” with the domain name of the website you wish to bypass. In both of these options, you can work around and bypass SSL verification. This does establish an insecure connection.

Here is another example to see:

$ curl https://expired.badssl.com/

curl: (60) SSL certificate problem: certificate has expired

$ curl https://expired.badssl.com/ -k

<!DOCTYPE html>

…

</html>

…

In this example, replace “badssl” with the website you are sending a request to, and it will create an insecure connection.

In both of these steps, you are telling the cURL commands to ignore the process of checking the SSL cert.

How to Use cURL to Skip SSL in the Script

While this method works for most needs, it is also possible to use cURL to skip SSL verification as a component of the code you are writing. If you want to ignore the SSL across the system, you will need to develop a bit more of a process.

One reason you may want to do this, for example, is when you are using cURL with Python. You could use the above command lines in the process, but that will be a long and complicated process. You do not want to have to go through every single request to set up this common.

In this situation, it is possible to create a cURL configuration file called ~/.curlrc

You can then add insecure to this. When you apply the insecure script, you disable SSL verification across the entire system. Keep in mind that you need to turn it back on to protect your users.

If you want to use cURL to ignore SSL verification in PHP, you will need to make a bit of a different change. Just set the following CURLOPT_SSL_VERIFYPEER to false or a 0. Use this code to help you:

Another option is to use SSL to ignore Libcurl with Python and PyCurl. The overall process is the same, and you will need to choose between ignoring SSL certificates in PyCurl or if you wish to use the libcurl directly. In either case, you need to adjust the SSL_VERIFYPEER and SSL_VERIFYHOST options by setting them to 0. To do that, you can use the following command lines:

The process is straightforward overall, using cURL to ignore the SSL verification steps it would normally take. As you use this process, make sure you do not continue to ignore SSl cURL. It is only safe to do so within the development phase in most situations.

Why Ignore SSL in cURL for Web Scraping

For those who are engaging in web scraping or the process of extracting valuable data from websites, it may be important to overcome, bypass, or otherwise work around the SSL certificates that are in place or may no longer be accurate. You can use cURL to ignore SSL error messages that show up during the process. You can also set it up to ignore SSL cURL in the script, which eliminates the risk of being stopped for this reason during your web scraping process.

Get the Support You Need at Scraping Robot

If you want to start scraping data, it helps to have one of the best resources by your side to handle the process. Check out what Scraping Robot has to offer and how you can use it to achieve your goals, even using it to use cURL to skip SSL during the process. Contact Scraping Robot with any questions you have.

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