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HTTPS is a way to transmit data securely over the internet, and it is important for both business owners and consumers. Website owner enables HTTPS port TCP 443 to secure web pages, online transactions, email communication, and other types of data transfers on the internet.
While running a site, we usually see ‘HTTPS’ or ‘HTTP’ at the start of the web address. The HTTPS site seems secure because of the padlock icon displayed at the address bar indicating the secure communication channel. Still, when we try to access a labelled HTTP site, the browsers tend to display a security warning stating “Not Secure”. This indicates the communication over this site is dangerous, and that’s where we need HTTPS.
Encryption configuration checks are one of the important pillars in our web application and API pen test methodologies.
HTTPS stands for HyperText Transfer Protocol Secure that is used to protect web browser communication. It secures the connection by encrypting the traffic transmitting over HTTPS port 443, protecting customer data in transit.
As an increasing number of people are using mobile devices with browsers that do not support HTTPS port 443 connections by default, we need to be more aware than ever about protecting our information when we’re browsing online. This blog post will give you all the basics you’ll need to know about HTTPS port 443.
What is the HTTPS port?
Before going into the details of HTTPS port, it is required to understand what does port actually mean and how it works. To define it in simple words, a port is an entry and exit point. In computer networking, a network port establishes an endpoint communication between two computers or mobile devices. When the website sends a service request to the web server, it uses a network port dedicated to the requested service. The server connects to the port and sends back the service, which the website will receive on the same port.
The transport layer of the TCP/IP (Transmission Control Protocol/Internet Protocol) model sets these ports, distinguished by the numbers with different network operations. These network ports are virtual and used for different services; for example, port 21 is used for FTP (File Transfer Protocol), port 53 is used for DNS (Domain Name System) etc. Their numbers identify the ports to guide different types of web traffic on a site.
What is port does HTTPS use?
IETF (Internet Engineering Task Force) has standardised protocols for certain ports. Technically, you can use port 443 for just HTTP traffic or 80 for HTTPS or any other port.
What is port 443?
HTTPS port 443 is used for the service of securing a communication channel between two devices, usually termed in the language of computer networking as a client, i.e. a web browser and a server, i.e. web server. It creates a secure channel by encrypting the traffic with the security certificates, i.e. SSL certificates.
As mentioned, all network ports are distinguished by port numbers for the specific services. Port 443 is globally used for HTTPS service that provides data authentication and encryption for the connection. The HTTPS traffic gets encrypted by using cryptographic algorithms called SSL/TLS. SSL (Secure Sockets Layer) uses an asymmetric encryption algorithm. At the same time, TLS (Transport Layer Security) is the more secure version of SSL that has addressed the security flaws of the previous version. Both protocols provide SSL certificates to enable the secure transfer of encrypted data over port 443.
Why do we use port 443?
The connection between a website and a server is made via port either by 80 or 443. Port 80 is used for HTTP service, which does not provide any security for the data to be travelled, while port 443 is used for HTTPS service that’s the main purpose is to secure the communication channel. If we talk about today’s era where the rate of cybercrimes is increasing rapidly, not securing the traffic could lead to the potential loss of sensitive data, i.e. passwords, credit card information, customer personal information, business-critical data etc. For that purpose, it is essential to use a secure channel where data is encrypted, and even if an attacker attempts to steal that data, he could not compromise it.
Because of the growing demand from the customers, the website owners make sure to secure their site with HTTPS port 443. People now prefer to make transactions on a site that supports HTTPS connections as it is safer. In contrast to HTTP, the data travels in plain text, which is likely vulnerable to compromise.
The below chart shows the approximate transmission of encrypted traffic over port 443 across Google as of 01 January 2021.
Is HTTPS always port 443?
Port 443 is primarily used for handling HTTPS traffic, but it is important to note that HTTPS traffic can also be transmitted over port 80. Using this port for HTTPS does not mean that your connection is secure. As mentioned, these ports are just entry and exit points distinguished by globally assigned numbers for ease of communication.
HTTPS Port 443
Port 443 guarantees that the site runs on an HTTPS version, but if port 443 is unavailable, the site will load on the insecure connection over port 80 if allowed by the website configuration.
Similarly, if you want to use any port other than 443 for HTTPS, a web owner will have to change the settings manually and make appropriate changes to avoid misconfiguration.
What is HTTPS protocol, and how it works?
The HyperText Transfer Protocol Secure is an HTTP extension that manages secure and reliable communication over the internet. The ‘S’ stands for the secure exchange of information between a client and the server. HTTPS is governed by the SSL/TLS responsible for encrypting the data throughout the entire communication and enabling the site more robust.
When a web page sends information to the server., it gets encrypted using SSL/TLS. It uses the asymmetric encryption algorithm that uses two encrypted and decrypts keys known as public and private keys. As the name suggests, the public key is distributed over the public network and available to everyone, while the private key is confidential and never disclosed to anyone. The public key is used to encrypt the traffic that is only decrypted by its private key. Both keys are generated together and are distinct from each other but mathematically related. No one can ever generate the private key from its public key and vice versa.
SSL/TLS establishes secure communication on a website by using SSL certificates. SSL certificate serves the purpose of authentication, which enables the encrypted connection. The whole process is called SSL/TLS handshake. An SSL certificate for multiple domains will allow you to secure domain names, including the main domain names and up to 99 SANs (subject alternative names).
How does HTTPS work step by step?
An SSL/TLS handshake process established a secure connection between a client (a browser) and the server. Here is a step by step SSL/TLS handshake process of how a website and a server uses the SSL certificates to negotiate the secure exchange of information.
- Client Hello: At first, the client browser sends a message “Hello” listing the information relating to the connection, i.e. SSL/TLS version, the encryption algorithm and the data compression methods supported by the server.
- Server Hello: After receiving the message, the server responds by sending a message “Hello” containing the encryption algorithm agreement, session ID, server’s digital certificate (or the SSL certificate) and the server’s public key.
- Authentication: The browser would check with the certificate authority (CA) to confirm the certificate’s authenticity issued to the webserver.
- Client Key Exchange: The client sends a premaster secret – a random string of bytes. The premaster secret is encrypted with the public key token from the server’s SSL certificate and can only be decrypted by the server’s private key. Now, the server decrypts the premaster secret sent by the client. Now, the client and the server both generate session keys.
- Finished(client): The client, i.e. the browser, sends a “finished” message encrypted by its private key indicating the browser’s part from the handshake process is completed.
- Finished(server): The server sends the ‘finished’ message encrypted with a session key and responds to the browser, indicating completion of the handshake process from its side.
- Secure symmetric encryption achieved: Once the handshake completes on both sides, it means a secure symmetric encryption setup has been achieved. The browser and the server now exchange information securely that is encrypted by their private keys.
After establishing the connection, the URL bar displays a padlock sign or an unbroken key in the status region – indicating the status of the secure connection.
TLS handshakes use asymmetric encryption (using the public key and private keys). All handshakes do not use the private key during the session key generation process, e.g. DH (Diffie-Hellman) handshake.
Keyless SSL is another important term to be aware of. Keyless, as the name says, is keyless, i.e. without private keys. Cloud vendors usually offer keyless SSL where service providers leverage the TLS usage without asking for private keys from the customer. This way is considered more reliable because customers do not feel safe sharing their private keys for multiple reasons. Therefore, a private key is still used without sharing outside the customer company.
During implementation, a server with the private key stays within customer control (cloud or on-premises). The cloud vendor’s server forwards the necessary data to perform the handshake process.
What is a certificate authority?
Certificate Authorities are trusted entities that verify SSL certificates. They ensure the website’s identity by providing an SSL certificate as a credential to authenticate the site.
Certificate authorities issue several digital certificates to guide people for trusted transactions on a website and play a vital role in a secure browsing experience.
What are HTTP and its purpose?
HyperText Transfer Protocol (HTTP Protocol) is a prior version of HTTPS that serves as the foundation of WWW (World Wide Web) communication. The client-server protocol’s main purpose is to govern how the traffic is modified and transmitted over the internet. It also defines what actions a client and the server should take while exchanging the information.
When we enter a URL in the address bar, a command is sent to the server directing it to fetch the requested web pages.
Some important features of HTTP
- HTTP is connectionless – Once a connection is established between the client and server, the server responds to the client for a requested service and the connection is destroyed. If the same client wants to request the same server, it will make a new connection again for each new request.
- Media independent – This means the client and server can exchange any data. Before transmitting any data, both client and server must specify the data type based on the relevant MIME standard.
For establishing a connection, a request is generated from the client to the server. The client website sends a request that contains a series of encoded data elements, including:
- URL indicates the requested resource on the web.
- HTTP version type indicates the version.
- HTTP method indicates the requested action to be performed by the server.
- Request headers indicate browser type, data type and cookies.
- The optional body indicates the option information needed by the server, i.e. user credentials or short-form responses submitted to the websites.
There are different methods use to request a specific task. Some of them are:
- GET requests information from the webserver.
- POST submits information to the webserver.
- DELETE removes the specified web resource.
- TRACE shows any changes made to the web resource.
- OPTIONS shows what methods are available for a web resource.
- PATCH modifies a web resource.
While responding to the request, the server sends a request status by issuing response codes as:
- 200 OK indicates the request is processed.
- 300 Moved Permanently indicates the requested URL has changed permanently.
- 401 Unauthorized indicates the client or server is not authenticated.
- 403 Forbidden indicates the client does not give access authorization.
- 404 Not Found indicates the requested resource does not exist.
- 500 Internal Server indicates the server has some issue and is unable to process a request.
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Is HTTP and HTTPS protocol secure?
To answer this question, you can observe the definition of both. A site uses HTTP to pass and fetch information in plaintext, while HTTPS makes a more secure and reliable connection by enabling encryption for the transportation channel.
HTTP port 80
An HTTP site assumes safe as long as you do not enter any sensitive information while browsing. Web developers designed HTTPS sites for online transitions, email communication or banking applications because it is safer.
Is HTTPS protocol secure?
The secure connection of HTTPS is based on the SSL or TLS version in use.
- SSL 1.0 was the first cryptographic algorithm but was never released publicly because of its flaws and vulnerabilities.
- SSL 2.0 was the first released in public but got replaced by SSL 3.0 for the poor security.
- Coming next, SSL3.0 was also found to have some security deficiencies, which created the modified algorithm known as TLS.
- After the release of TLS, both SSL 2.0 and 3.0 were deprecated. The TLS 1.0 and its later version 1.1 were both deprecated by Google, Microsoft, Apple and Mozilla due to its identified vulnerabilities.
- The commonly used secure versions for the HTTPS connection are TLS 1.2 and 1.3, which are reliable and assure the protected connection.
The following table will summarize the website support of SSL/TLS versions as of April 2021 gathered by Wikipedia:
|SSL/TLS version||Website Support||Security|
|TLS 1.2||99.40%||Depends on ciphers and client mitigations|
The less percentage of TLS 1.3 is due to the web browsers limited support to this version. The above stats conclude that there are a considerable amount of users who stick to the old SSL versions for which they are vulnerable to the insecure HTTPS connection.
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How to use 443?
On a Windows system, you can enable port 443 through the control panel – systems and security – firewall. Add a new inbound rule for rule type: TCP, specified local ports: 443 and action: allow the connection. It will ensure TCP 443 traffic is allowed into your system through the Windows host firewall.
Can I use port 443 for HTTP?
You can run HTTP on any port. However, port 443 is strictly for HTTPS and using well-defined ports would mean users do not have to specify the port number. For example, a user visiting https://thecyphere.com/ will see their browser making an HTTPS request.
Port 80 is used by web servers to listen for requests from the public internet. Port 89 can be used as a substitute if you want people to access your site over insecure connections (the same way they would with port 80).
Intruding unencrypted data over a vulnerable channel is one of the common examples of cyber attacks. The data travelling in plain text without any encryption applied to it can be easily compromised if it goes into the wrong hands. That data could be the user’s personal information including credit card data, usernames and passwords, IP address, business data and many more. To avoid this risky approach users prefer a safe internet connection to communicate where the data is less likely to be compromised.
To serve this purpose, HTTPS comes in that provides a secure channel between the client and the server. It uses a network port 443 to transmit the encrypted web traffic over the internet. The standard port for HTTPS is 443. HTTPS provides encryption by using an SSL certificate.
HTTP is the prior version of HTTPS that serves the purpose of loading web pages using hypertext links. It governs the client and server on how to communicate over the internet. HTTP does not provide any protection to the data while transmitting and does not support any encryption.