HTML INJECTION
HTML Injection: An In-Depth Look:
To gain a better understanding of HTML Injection, we must first understand what HTML is.
HTML is a markup language in which all of the parts of a website are written in tags. It is mostly used to create websites. HTML documents are used to deliver web pages to the browser. The HTML papers are then turned into conventional websites, which are then shown to the end-users.
What is HTML Injection and how does it work?
Injecting HTML code through susceptible portions of the website is the essence of this sort of injection attack. The malicious user injects HTML code into any susceptible field with the intent of altering the website's appearance or any information presented to the user.
As a result, the user may be able to see the data that the fraudulent user transmitted. As a result, HTML Injection is just the injection of markup language code into the page's document.
The data that is delivered during an injection attack might be completely different. It might be a few HTML elements that just display the data supplied. It might also be the entire bogus form or page. When this happens, the browser normally views malicious user data as legitimate and shows it to the user.
This form of assault poses more than just a threat to the aesthetic of a website. It's analogous to an XSS attack, in which a rogue user takes on the identities of others. As a result, identity theft might occur as a result of this injection attack.
Recommended Tools
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Types of HTML Injection
HTML is a very basic language, so this attack does not appear to be difficult to comprehend or execute. This sort of attack can, however, be carried out in a variety of ways. Different types of injections can also be distinguished.
To begin, different types can be classified according to the risks they pose.
As previously stated, this injection attack may be used for two purposes:
● to alter the look of the displayed webpage.
● to take someone else's identity.
This injection attack may also be carried out through other elements of the website, such as data input forms and the website's URL.
The following are the most common types:
● Stored HTML Injection
● Reflected HTML Injection using
The primary distinction between these two kinds of injection is that a stored injection attack happens when malicious HTML code is saved on the webserver and is performed every time a user requests a certain function.
However, malicious HTML code is not permanently retained on the website in the event of a reflected injection attack. When a website replies quickly to malicious input, this is known as a "reflected injection."
HTML injection that is reflected:
This can be further subdivided into the following categories:
Reflected GET
Reflected POST
Reflected URL
Depending on the HTTP methods used, such as GET and POST, a Reflected Injection attack can be carried out in a variety of ways. I'd like to point out that data is sent using the POST method and data is requested using the GET method.
A tester, for example, can look at the source code for the login form to see what method is being utilized. Then the proper HTML injection technique may be chosen.
Reflected Get: When our input is presented (reflected) on the website, injection occurs. Assume we have a basic search form on a page that is vulnerable to this attack. Then, if we input any HTML code, it will show up on our website and be injected into the HTML content at the same time.
For example, we use HTML elements to insert simple text:
When HTML code is supplied over the website URL, it is shown on the website and injected into the website's HTML page at the same time.
What is HTML Injection and how does it work?
To carry out this sort of injection, the malicious user must first identify weak areas of the website. Data input forms and the website's URL, as previously said, maybe susceptible portions of the website.
InnerHTML allows malicious HTML code to enter the source code. Let's recall that innerHTML is a DOM document attribute that allows us to construct dynamic HTML code. It is mostly used for data input fields such as comment fields, questionnaire forms, and registration forms, among other things. As a result, some components are particularly sensitive to HTML attacks.
Assume we have a questionnaire form on which we must fill in relevant responses as well as our names. When the questionnaire is completed, a message of acknowledgment appears. The name of the indicated user is also included in the acknowledgment message.
The message may look like this:
As far as we can tell, Tester_name is the name given by the user. As a result, the acknowledgment message code can look like this:
var user_name=location.href.indexOf(“user=”);
document.getElementById(“Thank you for filling our questionnaire”).innerHTML=” Thank you for filling our questionnaire, ”+user;
Such an attack is possible using the code shown. If we enter any HTML code into the questionnaire form, the message will appear on the acknowledgment page.
The same thing happens in the comment areas. If we have a comment form, for example, it is subject to an HTML assault.
The user fills out the form with his name and the content of his comment. On page load, all stored comments are listed on the page and loaded. As a result, malicious code that has been written and saved will be loaded and displayed on the website.
For example, if we save the code in the comments area as shown below, a popup window with the phrase "Hello world!" would appear when the website loads.
Another technique to execute this sort of injection is to use the website's link. Assume we have a URL to a PHP website.
As we can see, "site" is a parameter with the value "1." Then, instead of specifying "1" for the field "site," we could specify any HTML code containing the text to show, and that text would be displayed on the "Page Not Found" page. Only if the page is vulnerable to an HTML attack does this happen.
Assume that instead of the parameter's value, we type a string.
Then, as seen below, the text would be shown on the website:
Furthermore, as previously stated, not just a portion of the HTML code can be inserted. The entire infected website might also be forwarded to the end-user.
For instance, suppose a user goes to any login page and enters his credentials. In this situation, if a malicious page is loaded instead of the original page and the user transmits his credentials through this page, the third party may obtain the user's credentials.
How Do You Test for HTML Injection?
Before beginning to test for probable injection attacks, a tester should make a list of all possibly susceptible portions of the website.
I'd like to point out that it may be:
● All of the data entry fields
● website link
Manual testing might then be carried out.
When manually checking whether HTML Injection is feasible, simple HTML code may be input — for example, to see if the text is shown. It is pointless to test with complex HTML code; basic code may be enough to see if it is shown.
For example, it might be simply texting tags:
Or search for form code if you want to test it with something a little more complex.
Type text to search.
If an HTML code that has been stored someplace is shown, the tester knows that this injection attack is conceivable. Then, for example, to display the phony login form, a more elaborate code may be tried.
The HTML Injection scanner is another option. Scanning automatically for this assault may save you a lot of time. As a comparison to other assaults, I'd like to point out that there aren't as many tools for HTML Injection testing.
The WAS application, on the other hand, is one viable option. WAS is a rather powerful vulnerability scanner because it checks with a variety of inputs and does not stop when the first fails.
It is useful for testing because, as indicated in the previous browser plugin "Tamper Data," it receives data, allows the tester to alter it, and then transmits it back to the browser.
We may also locate various online scanning programs that require only the URL of the website to be provided before screening for HTML attacks. The summary will be presented once the testing is done.
I'd like to add that while choosing a scanning tool, we must consider how it analyzes the findings and whether it is accurate enough.
However, it should be remembered that manual testing should not be overlooked. In this manner, we can be certain of the specific inputs used and the exact outcomes obtained. It is also easy to assess the results this way.
I would want to add that for both testing methods, we should be well-versed in this sort of injection. Otherwise, selecting an appropriate automation tool and analyzing its outcomes would be challenging. Furthermore, it is usually advisable not to forget to test manually, as this just increases our confidence in the quality.
How Can HTML Injection Be Avoided?
There is no question that the developer's inattention and lack of expertise are the primary causes of this attack. This form of injection attack happens when the input and output are not adequately vetted. As a result, the most important criterion for preventing HTML attacks is proper data validation.
Each input should be examined to see whether it includes any script or HTML code. If the code contains any specific script or HTML brackets – it is usually examined.
There are a number of functions that may be used to see if the code has any special brackets. The checking function you use is determined by the programming language you're using.
It's important to remember that security testing is an important aspect of prevention. I'd like to draw your attention to the fact that because HTML Injection attacks are uncommon, there are fewer scanners to choose from for automated testing. This aspect of security testing, on the other hand, should not be overlooked because you never know when something bad can happen.
Furthermore, both the developer and the tester should have a thorough understanding of how this attack is carried out. Understanding how this attack works will help you avoid it.
Other Attacks in Comparison
In comparison to other conceivable attacks, this one will most likely not be deemed as dangerous as SQL Injection, JavaScript Injection, or even XSS. It will not completely delete the database or take all of the data from it. It should not, however, be dismissed as inconsequential.
As previously said, the primary goal of this sort of injection is to alter the design of the displayed website for harmful purposes, thereby revealing your provided information or data to the end-user. Those dangers might be regarded as minor.
However, changing the design of your website might harm your company's reputation. If a malevolent person defaces your website's appearance, it may influence visitors' perceptions of your firm.
It should be noted that this website attack also poses the possibility of stealing the identities of other users.
As previously stated, HTML Injection allows a malicious person to inject the whole page that would be presented to the end-user. The ultimate user's login data will then be provided to the malicious user if he enters it on the phony login page. Of course, this is the most dangerous aspect of the strike.
It's worth noting that this type of attack isn't used very often to steal data from other users because there are so many other options.
It is, however, quite similar to the XSS attack, which takes the user's cookies as well as the identities of other users. XSS attacks, which are HTML-based, are also possible. As a result, testing for XSS and HTML attacks may be quite similar and done at the same time.
As we've seen in this article, this form of injection may cause your website's entire design to be ruined, or even the user's login credentials to be taken. As a result, including HTML Injection in security testing and investing in strong expertise is highly advised.
Conclusion
Because HTML Injection isn't as common as other attacks, it's possible that it's less dangerous. As a result, testing for this form of injection is occasionally omitted.
It's also worth noting that there's a dearth of literature and knowledge on HTML Injection. As a result, testers may choose not to do this sort of testing. However, in this scenario, the hazards of an HTML assault may not have been well assessed.