Cross-Site Scripting (XSS) Mitigation/Prevention

Cross-site scripting is universally referred to as XSS. It illustrates a web security risk, which is commonly present in applications and can result in extreme damage if no proper mitigating measures are implemented in perfect timing. Cross-site scripting mitigation is necessary to eliminate any chances that attackers may have, which may enable them to gain full control over the entire functionality plus data of an application.

Cross-site scripting attacks are classified into two types, namely stored XSS and reflected cross-site scripting attacks. Stored XSS attacks occur when the attack performs direct injection of the malicious script into the susceptible application. On the other hand, reflected cross-site scripting attacks arise when the attacker performs malicious script’s reflection into a page’s link. When a user clicks on the link, the attack gets automatically activated.

Cross-site scripting vulnerabilities enable a cyber-attacker to come in between the interactions, which exist between users and a susceptible application. XSS vulnerability is common and has impacted significant applications such as Facebook, Google, plus PayPal.

Cross-site scripting susceptibilities are very treacherous as they usually enable an invader to pretend as a target user in order to perform any activities, which the user can execute and gain access to the user’s data. For instance, if successful in launching its attack, the invader can view passwords, payment plus financial data, and so much more. What is eviler and very disturbing is the fact that both victims, the user plus the application, at most times, are unaware of the attack.

Cross Site Scripting Mitigation

Cross-Site Scripting Mitigation Measures

Given that you now have some basic understanding as to what XSS attacks are and their detrimental effects, it is of significance that you also have some background knowledge on cross-site scripting prevention and mitigation if they are to occur.

1. Escaping

This is the initial cross-site scripting mitigation measure you should employ to deter XSS susceptibilities from making an appearance in your apps. It is all about escaping user input, which involves securing the data received by an application prior to it being delivered to the final user. As the user inputted data is escaped, the main characters present in the data the web page obtains are protected from being maliciously interpreted. In essence, by escaping user input, you censor the information your web site gets, which prevents the characters from being extracted, which would ordinarily endanger applications plus users.

In scenarios where your site disallows users from including their codes to your site, ensure that you escape every HTML, URL, plus JavaScript unit.

2. Validating input

Input validation revolves around the act of ascertaining that the accurate data is being rendered by an application while at the same time blocking malevolent data from causing damage to the web page, database, plus users. Input validation, together with whitelisting are utilized as further preventive measures for XSS attacks. Blacklisting prohibits the identified evil characters only, whereas whitelisting permits recognized good characters, thus aids in preventing XSS attacks better.

Input validation is incredibly beneficial and better at averting XSS attacks in forms. It deters the addition of unique characters by the users into the forms, other than declining the application. Even though input validation is not considered the main method of deterring vulnerabilities, it is still essential in minimizing the impacts in case an attacker learns of the weakness.

3. Sanitizing

Sanitizing user input is another effective way of prevent XSS attacks. Even though it is a robust defence, it should be used combined with the two mitigation methods mentioned above. Sanitization ought not to be utilized singly to mitigate XSS attacks. Utilizing the above three mitigation procedures will enable you to attain an extremely safe application.

Sanitization is especially beneficial with web pages that permit HTML markup. It cleans off possibly detrimental markup, hence ensuring that the data obtained is harmless to both your users plus your database. Therefore, sanitization transforms user input that is undesirable into a suitable format.

4. Using suitable response headers

This is where Content-Type options plus X-Content-Type-Options headers are utilized towards guaranteeing that browsers infer the retorts in an intended way. This will aid in inhibiting XSS present in HTTP reactions, which are not designed to comprise some HTML or JavaScript.

5. Content security policy

This is often applied as a last option of mitigation so as to minimize the brutality of any XSS susceptibilities that may still arise.


Utilizing the above cross-site scripting mitigation procedures will ensure that your users plus the applications are safe from XSS attacks. Hence, implement these procedures, and you can be sure of blocking any attempted XSS attacks from occurring.

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