Web Application Security Testing

Web application security testing is a method that helps security and development teams uncover vulnerabilities in web applications. These vulnerabilities can be caused by a variety of factors, including input validation and error handling, server configuration, and client-side logic.

There are several types of testing tools available, and choosing the right one can be tricky. Here are a few things to keep in mind:

Cross-Site Scripting

Cross-Site Scripting, or XSS, is a common web application security issue that can lead to malicious code being injected into websites. It affects websites and web applications that lack effective input validation, as well as web pages where user-controllable data is output in HTTP responses.

Modern web applications are robust and powerful tools that allow users to interact with a wide range of functions. These include things like online file management, text editing, and spreadsheets. Many modern websites use JavaScript to perform these functions.

One of the most important aspects of web application security testing is to ensure that input is properly validated on arrival and that any output that could contain user-controllable data is encoded before being sent. This requires applying combinations of HTML, URL, and JavaScript encoding at the point where user-controllable data is received or produced in an application.

Moreover, it is critical to check whether any typed scripts or encoded brackets are being executed by the website. This is crucial as it can be a precursor to a more harmful attack, for instance a cookie might be sent to the user or a fake page might be displayed in their browser.

A common example of a vulnerable website is an online forum, where attackers can post messages containing embedded JavaScript that will be saved in the system database and executed on page load as the latest user opinion is shown. This will result in a popup window with cookies being displayed or a fake page being displayed.

Another vulnerability that can occur is stored XSS, which occurs when an attack vector contains JavaScript that doesn’t come in the user request but is downloaded from the server (such as the database or file system). This happens when the application fails to properly handle HTML escape sequences in a way that makes it possible for attacker-controlled JavaScript to be included in a user request.

Other forms of XSS are reflected XSS, which happens when an attacker sends an HTTP request that includes an XSS payload and the Hypertext Transfer Protocol response is reflected back. This happens when the attacker delivers the XSS payload to the victim using phishing or other social engineering techniques.

URL Manipulation

One of the main vulnerabilities that can be exploited by attackers is URL manipulation. This attack allows hackers to manipulate the query strings of a web page and get access to confidential information or malicious script.

A URL (Uniform Resource Locator) is a unique identifier that tells a web browser how to find a website, file, video, application or other resource on the Internet. It consists of five parts and can’t be longer than 2,083 characters.

Using the browser’s address bar, users type in a URL and press Enter to navigate to a specific site or page. They can also use hyperlinks found on websites, in emails and other applications.

Manipulating URLs can lead to a variety of attacks, including directory traversal, path traversal and XSS injection. These vulnerabilities can allow hackers to access privileged sections of a website or steal confidential data, such as credit card numbers and medical details.

The most common form of URL manipulation is modifying the URL to force it to redirect to an unauthorized site. This can be achieved by altering the Referer header, which normally contains the URL of the original site. This can be manipulated by an attacker to look like it came from the original site, thus increasing the likelihood of a successful phishing attack.

Another way to manipulate URLs is through a technique called HTTP Parameter Pollution. This is a problem that affects almost every web application, as it exposes an extensive variety of input validation or injection vulnerabilities to attackers.

Hackers can abuse HTTP Parameter Pollution to perform client-side or server-side hacking activities, depending on how the parameters are interpreted. It’s important to test whether a web application is vulnerable to this vulnerability, as it can allow attackers to modify any of the application’s HTTP request parameters to carry out a wide variety of exploits, such as Cross-site Scripting or SQL Injection.

In order to mitigate this vulnerability, testers should ensure that the application does not accept or process any of the parameters it receives from an external source. They should also make sure that the application does not use a rewrite engine to modify URLs, as this can increase the risk of a XSS injection attack.

SQL Injection

SQL Injection is a common type of attack that allows hackers to gain access to sensitive information on a website. This is a serious vulnerability that affects many applications and can lead to severe consequences.

Web application security testing is essential to prevent this vulnerability. It involves securing the database, web servers, and application code from unauthorized data manipulation.

The first step is to determine whether an attacker could use a web application to perform a successful SQL Injection. This is done by using a web vulnerability scanner that can test for this technique by injecting special characters into the input fields of the application and watching for responses.

This is a quick and easy way to identify SQL Injection vulnerabilities. The tool inserts special characters into all the input fields of a website and monitors its response. If it finds any database errors on the site, it is a good indication that there is an SQL Injection vulnerability.

A good way to protect against SQL injection is by implementing input validation in the application and using parameterized queries. These queries add values to an SQL query at execution time, but they are treated as placeholders rather than part of the SQL statement that is being executed.

Moreover, developers should never use a web form input to send SQL commands directly to the server. They should only send data that has been properly sanitized by input validation.

To avoid exposing an application to this risk, it is recommended that a developer implement a web application firewall (WAF) and run it on the server hosting the application. A WAF will automatically block an incoming connection that may contain malicious data.

Another effective strategy is to prevent this exploit by avoiding stacked queries and ensuring that the database is not exposed to internal SQL errors. These errors are typically displayed to users and can be used to extract data from the underlying database.

SQL Injection is a security risk that should be addressed by all organizations. A successful exploitation of this vulnerability can allow an attacker to alter, delete, or add information to the database. This can affect the integrity of a system and the credibility of the company it represents.

Authentication

Web application security testing often involves verifying a user’s identity and permissions. This is a critical part of web application security because it prevents malicious users from gaining access to an information system and stealing data.

The primary authentication factors are a user’s name, password, and something the user possesses (such as a keychain or mobile device). These can be combined with other types of authentication, including facial scanning, fingerprint matching, or blood testing.

Another important aspect of authentication is the strength of the password used by a user. If the password is weak or is guessed, it can easily be exploited to gain access to an information system or to steal data.

For this reason, it is essential to test password strength and the proper setting of timeouts. Passwords should be changed regularly and re-hashed after each update, and they should also be stored in a secure location, away from the application that uses them.

Additionally, web applications should limit session timeouts to a specified period, such as 30 minutes or 24 hours. This will prevent a user from logging into the application multiple times in a short period of time, which may lead to session replay attacks.

In addition, testers should test the way that a web application handles user input and error handling. For instance, many common injection vulnerabilities can be caused by faulty input handling or by errors that occur when a web application attempts to use input variables that are not properly escaped.

This can result in SQL injection, cross-site scripting (XSS), and other forms of injection vulnerabilities that affect the integrity of data stored on a database. This type of vulnerability is especially common for websites that have a large number of user inputs or that exchange data with a third party via an API.

Web application security tests should include a wide range of security testing techniques, including user identification and authentication, coding and testing of server-side logic, and client-side logic. The latter includes identifying and evaluating the security of APIs and other interfaces that are used by the web application, such as APIs, CDNs, and content repositories.