What is Web Server Attacks

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By Sameeksha Medewar

Over the last decade, the online world has become a hunting ground for fraudsters. In 2021, 30% of web applications are vulnerable to XSS attacks (source). On the other hand, more than 30,000 websites are being hacked each day(source). These numbers are truly shocking, and no matter what we do, numbers like these will only increase in the coming years. Think about a fraud in which a person doesn’t have to be close to you physically. A hacker just puts some malicious software on your system, and when you are making any online purchase, the software will capture sensitive information like your card details that hackers can use to commit fraud.

Online fraud is more likely to happen when you are making a payment. The hacker will make you pay to them instead of the original website by taking you to their web page and letting you enter your card’s credentials, and make the payment straight to them. You won’t even know you have been robbed, and the money will be transferred to their accounts. Also, once the page has been redirected or closed, there is no way you can trace it back as it’s been taken down by the hacker.

To keep your online business and your customers safe from these types of fraudulent activities, you must know about various types of web server attacks and how to protect your website from them. Today, we will show you some of the most harmful web server attacks, which are running big on the internet and making websites lose their data and customers. In addition to this, we will share the precautions that you can take to keep the website and the server safe from such attacks and ensure the safety of your online business. A fraud attack is more likely to happen when you are making an online payment.

What is a Web Server?

All the websites that are active on the internet are hosted on web servers. Hosting is more like a storage space, where all the website data and other information is stored. Web servers are nothing but computers running on any server operating system. They are connected to the back-end database and run many applications to provide the necessary support to all the websites it hosts. If you are thinking of websites to be placed in a slot present in the server, you are not wrong. But the storage space is not divided into equal parts, and if your website requires more space, you can get it on the same server without worrying about shifting to a new server.

There are two methods by which you can host your website on a server, and the first one is shared web hosting. In shared website hosting, your website is hosted on a server that also hosts multiple other websites simultaneously. Your website shares all the hardware resources of the server with other websites. On the other hand, the second one is private web hosting or dedicated hosting in which your website gets a dedicated server. Only your website is running on that server, and if you want to include any more websites, you are free to do that. However, you should know that all the resources of the server hardware will be completely under your control and you don’t have to share them with any other customers.

What is a Web Server Attack?

Now that you know the difference between a shared and private web server, let’s talk about the webserver attacks on these two. Any vulnerability in the applications, database, or even in the operating system can lead to a potential attack on your web server. Both shared and private servers can be attacked by hackers. However, the chances of hacking increase with the increase in the number of websites hosted on a single server. If your website is privately hosted, it’s your responsibility to ensure the security of your website as well as the server. 

In case one of the websites gets affected by the attack and there are other websites on the same server, then the security of all the websites is at risk.

What are the Security Issues Related to a Web Server? 

Every now and then, we get to hear that some popular website has been hacked and taken down by a group of hackers. Now, these types of news have become a standard norm in our daily lives. However, in 2020, we got to hear a whole new set of cyber threats that could bankrupt businesses if they don’t stay vigilant enough. There are three main themes for any web server cyber attack:

  • Disruption

Most of the attacks fall into this category, and they are aimed to disrupt the normal working of the server and cause havoc to the websites that are being hosted on it. In addition to this, once the server is being hacked, all the applications and websites present on the server can be locked and hackers may ask for a ransom.

  • Distortion

This theme corresponds to the act of hackers that involves spreading fake news or misinformation. One of the great examples of this type of attack was done in early 2021. When the Twitter account of famous celebrities, sports personalities, and even politicians was hacked, all of those accounts had tweeted about the fundraiser to help the needy. But in truth, it was a group of hackers asking the celebrities’ followers to pay the money that will go into their personal accounts.

Also, the hackers were able to make millions from this attack as people actually paid them, thinking they were paying for a better cause. As a result, the attack led to the distortion of the correct information, and people’s trust was compromised. The hackers were able to access so many Twitter accounts because they could breach the server that hosts those Twitter accounts.

  • Deterioration

The last theme is deterioration which becomes evident when the attackers are trying to get the upper hand over the server’s security features. For example, they might aim to gain control of the different applications that are being hosted by a server. Once the attackers take control of the applications, they can exploit the user data and get personal information like phone numbers and email IDs.

Top 7 Web Server Attacks

It’s true that every server comes integrated with a firewall, but it doesn’t guarantee complete protection against most server attacks. Apart from the firewall, a hoisting service provider needs to have advanced security features baked into their server software to make sure that all the websites present in the servers are well protected.

Nonetheless, here are the 7 most infamous web server attacks:

  1. URL Interpretation Attack

This attack is also known as URL poisoning as the attackers try to manipulate the URL by changing the semantics of the URL but keeping the syntax exactly the same. This way, an attacker can fool a customer into making the payment to their portal and resulting in customers sending money to the hacker’s account rather than the intended website. Also, the hacker uses this attack to lure users into paying them to adjust the parameters of the URL so that the information can be easily retrieved from the web server.

Likewise, the URL interpretation attack is also used to hack emails. A hacker can use it to reset the password of the user by answering security questions. After the page of security, queries have been redirected, and the application will be opened where the user can set the alternative email address. The URL received on the alternative email address allows the hacker to change the password of the email. Also, the same URL will have all the information with respect to that email ID. As a result, the URL Interpretation attack makes the information of the online users quite vulnerable if the websites are not vigilant about it. 


The URL interpretation attack can be controlled by applying the fix from the vendor. Also, the website can do a thorough, in-depth checking and verification of the web server configuration. 

  1. SQL Injection Attack

The SQL injection attack aims at the database of the website and makes changes in it. Many attackers use this method to retrieve sensitive information from the database. An SQL query is sent to the database, which holds the URL parameters. Once it enters the database, the query will alter the database according to the attacker’s needs. Moreover, once the SQL injection is done, the query will remain there while being inactive. Once the attacker wants to do something with it, they can activate it, and it will perform the task.

When this attack takes place, the database that gets affected by it can suffer from data loss. This attack takes place when the SQL query is permitted to be executed even though its input data hasn’t been validated. The most common websites that are vulnerable to this type of attack are e-commerce websites.


It is hard to get rid of this attack once it affects your database. You need to review your full source code and check all the DB applications, even the ones that have the least privilege. Moreover, you might need to delete the redundant and unnecessary database of users and query procedures that aren’t of any use to your website data.

  1. Cross-Site Scripting (XSS) Attack

In a cross-scripting attack, attackers try to exploit the vulnerability, which gives them access to inject malicious scripts into the database of the website. Thus, when a user from the website requests some data, the infected script runs, and the browser will open the faulty web page without notifying the user. As a result, the attacker will steal the browser cookies, which leads to session hijacking. Once the session hijacking is done, the attacker gets all the information they need. It can exploit the information and gain the potential control of the computer or the network. This type of attack leads to a snowball effect; thus, if one system in the company gets affected, the whole network gets compromised.

With the help of session hijacking, the attacker gets to access all the account information which was being used in that session. Meaning, all the passwords, usernames, and even your card credentials can be compromised.


One can keep themselves away from malicious websites, and if the attack has already been performed, then you need to check the server side tracking id and match the timestamps of every connection with the associated IP addresses. In case the session IDs are generated cryptographically, they will be much harder to decipher. As a result, you need to take help from server session management API, which could be helpful in the prevention of session hijacking attacks in the future.

  1. Brute Force

Brute force attacks are used to obtain personal information like passwords, passphrases, usernames, and personal identification numbers. The brute force attack is orchestrated using scripts. The hacker keeps on trying different forms of attacks and uses various scripts until he gets the information that he needs from the system. As a result, the hacking technique is named brute force attack. An attacker is equipped with automation software that keeps on checking the passwords until the software is able to find the right password. Some of the famous examples of brute force attack tools are John the Ripper, Rainbowcrack, etc.


The brute force attacks can be stopped if your password strength is good and there is no careless network administration. You can use two-step verification to make sure that when you log in to a new system, the website asks you to provide the OTP, which is generated automatically and sent to your registered email ID or phone number.

Also, there should be a limited number of logins. Thus, if someone tries to hack into your email id, they don’t have an infinite number of login tries. Two-factor authentication is more than enough to tackle brute force attacks.

  1. Denial Of Service (DOS)

DOS is one of the most common attacks on the internet, and it makes the server go numb. Basically, what happens is that the server denies the requests which are coming from the users. There are a number of ways by which one can perform the DOS attack, and the most common method is by filling up the buffer flow. The attacker, after gaining access to the network, randomizes the attention of the security software of the server. As a result, the software doesn’t know the attack is happening and continues to work normally, allowing the hacker to send in millions of requests at the same time. DOS attacks are categorized as volume attacks, protocol attacks, and application-layer attacks.


The very first thing that you need to do is to implement a web server firewall that inspects the entire HTTP traffic that is coming from the web. This firewall will provide a barrier and filter to the malicious data packets generated by an unknown source. On the other hand, the maintenance staff needs to keep a close eye on the network audit trail so that new changes which are done over a period of time can be easily tracked. The network needs to be constantly tested both locally and on the internet.

  1. Zero-day attack

A zero-day exploit is basically the attacker getting their way around the software before the new patch rolls in by the developers. Now you might be thinking, how come this webserver attack is called a zero-day attack? Well, if you think about it, the latest update or a patch rolled out by a company is said to be done on day one. So, the hack which happens before the day of the update rollout is called a zero-day attack. These attacks are aimed to target the issues which haven’t been fixed by the concerned party.


A number of zero-day attacks take place right after Microsoft Windows does an update. As a result, the users who don’t update their system were left open for this type of attack. Thus, the next time you get an update notification, make sure you click on the okay button and download the update.


  1. Input Validation Attack 

An input validation attack is one in which the server gets an infected code that is sent by the attacker. There are a number of input types that need to be validated before the execution of the data takes place. The attacker executes the code with inputs that are not validated, and thus, the information is retrieved or gets modified by the attacker.

Moreover, the attack is made by bypassing the client-side system, which checks and authenticates the JavaScript code. The negligence of writing a proper code and trusting the unknown data packets which are designed to be received by a website leads to such attacks.


The only thing a website owner can do is, hire a well-trained coder who can use different security measures to keep the code secure and less vulnerable against attacks. The code needs to have the provision for validating the inputs, not just one or two, but all of them, including the data ranges, metacharacters, and even the buffer size.


So, these were some of the most dangerous web server attacks which can be used by attackers to harm websites and web apps hosted on servers. A server is just a storage space, and an attacker aims to damage the data and the websites which are being hosted on the server. 

With each attack that we have discussed, we told you about the precaution that you can take to keep your web server safe. If you keep these precautions in your head and use them often, you can secure your server in a much better way.

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