Burp Suite Alternative Open Source

2/14/2022by admin

In this section, we'll describe DOM-based cross-site scripting (DOM XSS), explain how to find DOM XSS vulnerabilities, and talk about how to exploit DOM XSS with different sources and sinks.

  1. Is Burp Suite Open Source
  2. Burp Suite Alternative Open Source Version
  3. Burp Suite Alternative Open Source Download
  4. Burp Suite Alternative Open Source Free
  5. Burp Suite Tutorial
  6. Burp Suite Tools
  7. What Is Burp Suite

What is DOM-based cross-site scripting?

The OWASP Zed Attack Proxy (ZAP) is one of the world’s most popular free security tools and is actively maintained by a dedicated international team of volunteers. Great for pentesters, devs, QA, and CI/CD integration. Download Burp Suite Community Edition Burp Suite Community Edition is a feature-limited set of manual tools for exploring web security. Proxy your HTTPS traffic, edit and repeat requests, decode data, and more. Get the latest version here. Train at your own pace to become a master ethical hacker for $43. Get the training you need for a brand new career in the tech industry, legally hacking some of the best-known apps and websites in. BadIntent is the missing link between the Burp Suite and the core Android's IPC/Messaging-system. BadIntent consists of two parts, an Xposed-based module running on Android and a Burp-plugin. Based on this interplay, it is possible to use the Burp's common workflow and all involved tools and extensions, since the intercept and repeater. Free and Open Source empire-building strategy game: freediameter: 1.5.0: Open source Diameter (Authentication) protocol implementation: freedink: 109.6: Portable version of the Dink Smallwood game engine: freeglut: 3.2.1: Open-source alternative to the OpenGL Utility Toolkit (GLUT) library: freeimage: 3.18.0: Library for FreeImage, a dependency.

DOM-based XSS vulnerabilities usually arise when JavaScript takes data from an attacker-controllable source, such as the URL, and passes it to a sink that supports dynamic code execution, such as eval() or innerHTML. This enables attackers to execute malicious JavaScript, which typically allows them to hijack other users' accounts.

To deliver a DOM-based XSS attack, you need to place data into a source so that it is propagated to a sink and causes execution of arbitrary JavaScript.

The most common source for DOM XSS is the URL, which is typically accessed with the window.location object. An attacker can construct a link to send a victim to a vulnerable page with a payload in the query string and fragment portions of the URL. In certain circumstances, such as when targeting a 404 page or a website running PHP, the payload can also be placed in the path.

For a detailed explanation of the taint flow between sources and sinks, please refer to the DOM-based vulnerabilities page.

How to test for DOM-based cross-site scripting

The majority of DOM XSS vulnerabilities can be found quickly and reliably using Burp Suite's web vulnerability scanner. To test for DOM-based cross-site scripting manually, you generally need to use a browser with developer tools, such as Chrome. You need to work through each available source in turn, and test each one individually.

Testing HTML sinks

To test for DOM XSS in an HTML sink, place a random alphanumeric string into the source (such as location.search), then use developer tools to inspect the HTML and find where your string appears. Note that the browser's 'View source' option won't work for DOM XSS testing because it doesn't take account of changes that have been performed in the HTML by JavaScript. In Chrome's developer tools, you can use Control+F (or Command+F on MacOS) to search the DOM for your string.

For each location where your string appears within the DOM, you need to identify the context. Based on this context, you need to refine your input to see how it is processed. For example, if your string appears within a double-quoted attribute then try to inject double quotes in your string to see if you can break out of the attribute.

Note that browsers behave differently with regards to URL-encoding, Chrome, Firefox, and Safari will URL-encode location.search and location.hash, while IE11 and Microsoft Edge (pre-Chromium) will not URL-encode these sources. If your data gets URL-encoded before being processed, then an XSS attack is unlikely to work.

Testing JavaScript execution sinks

Testing JavaScript execution sinks for DOM-based XSS is a little harder. With these sinks, your input doesn't necessarily appear anywhere within the DOM, so you can't search for it. Instead you'll need to use the JavaScript debugger to determine whether and how your input is sent to a sink.

For each potential source, such as location, you first need to find cases within the page's JavaScript code where the source is being referenced. In Chrome's developer tools, you can use Control+Shift+F (or Command+Alt+F on MacOS) to search all the page's JavaScript code for the source.

Once you've found where the source is being read, you can use the JavaScript debugger to add a break point and follow how the source's value is used. You might find that the source gets assigned to other variables. If this is the case, you'll need to use the search function again to track these variables and see if they're passed to a sink. When you find a sink that is being assigned data that originated from the source, you can use the debugger to inspect the value by hovering over the variable to show its value before it is sent to the sink. Then, as with HTML sinks, you need to refine your input to see if you can deliver a successful XSS attack.

Exploiting DOM XSS with different sources and sinks

In principle, a website is vulnerable to DOM-based cross-site scripting if there is an executable path via which data can propagate from source to sink. In practice, different sources and sinks have differing properties and behavior that can affect exploitability, and determine what techniques are necessary. Additionally, the website's scripts might perform validation or other processing of data that must be accommodated when attempting to exploit a vulnerability. There are a variety of sinks that are relevant to DOM-based vulnerabilities. Please refer to the list below for details.

The document.write sink works with script elements, so you can use a simple payload, such as the one below:

document.write('... <script>alert(document.domain)</script> ...');

Is Burp Suite Open Source

LABDOM XSS in document.write sink using source location.search

Note, however, that in some situations the content that is written to document.write includes some surrounding context that you need to take account of in your exploit. For example, you might need to close some existing elements before using your JavaScript payload.

LABDOM XSS in document.write sink using source location.search inside a select element

The innerHTML sink doesn't accept script elements on any modern browser, nor will svg onload events fire. This means you will need to use alternative elements like img or iframe. Event handlers such as onload and onerror can be used in conjunction with these elements. For example:

Suite

element.innerHTML='... <img src=1 onerror=alert(document.domain)> ...'

LABDOM XSS in innerHTML sink using source location.search

If a JavaScript library such as jQuery is being used, look out for sinks that can alter DOM elements on the page. For instance, the attr() function in jQuery can change attributes on DOM elements. If data is read from a user-controlled source like the URL and then passed to the attr() function, then it may be possible to manipulate the value sent to cause XSS. For example, here we have some JavaScript that changes an anchor element's href attribute using data from the URL:

$(function(){
$('#backLink').attr('href',(new URLSearchParams(window.location.search)).get('returnUrl'));
});

You can exploit this by modifying the URL so that the location.search source contains a malicious JavaScript URL. After the page's JavaScript applies this malicious URL to the back link's href, clicking on the back link will execute it:

?returnUrl=javascript:alert(document.domain)

LABDOM XSS in jQuery anchor href attribute sink using location.search source

If a framework like AngularJS is used, it may be possible to execute JavaScript without angle brackets or events. When a site uses the ng-app attribute on an HTML element, it will be processed by AngularJS. In this case, AngularJS will execute JavaScript inside double curly braces that can occur directly in HTML or inside attributes.

LABDOM XSS in AngularJS expression with angle brackets and double quotes HTML-encoded

DOM XSS combined with reflected and stored data

Some pure DOM-based vulnerabilities are self-contained within a single page. If a script reads some data from the URL and writes it to a dangerous sink, then the vulnerability is entirely client-side.

However, sources aren't limited to data that is directly exposed by browsers - they can also originate from the website. For example, websites often reflect URL parameters in the HTML response from the server. This is commonly associated with normal XSS, but it can also lead to so-called reflected+DOM vulnerabilities.

In a reflected+DOM vulnerability, the server processes data from the request, and echoes the data into the response. The reflected data might be placed into a JavaScript string literal, or a data item within the DOM, such as a form field. A script on the page then processes the reflected data in an unsafe way, ultimately writing it to a dangerous sink.

eval('var data = 'reflected string');

Websites may also store data on the server and reflect it elsewhere. In a stored+DOM vulnerability, the server receives data from one request, stores it, and then includes the data in a later response. A script within the later response contains a sink which then processes the data in an unsafe way.

Burp suite alternative open source free

element.innerHTML = comment.author

LABStored DOM XSS

Which sinks can lead to DOM-XSS vulnerabilities?

Burp Suite Alternative Open Source Version

The following are some of the main sinks that can lead to DOM-XSS vulnerabilities:

document.write()
document.writeln()
document.domain
someDOMElement.innerHTML
someDOMElement.outerHTML
someDOMElement.insertAdjacentHTML
someDOMElement.onevent

The following jQuery functions are also sinks that can lead to DOM-XSS vulnerabilities:

add()
after()
append()
animate()
insertAfter()
insertBefore()
before()
html()
prepend()
replaceAll()
replaceWith()
wrap()
wrapInner()
wrapAll()
has()
constructor()
init()
index()
jQuery.parseHTML()
$.parseHTML()

How to prevent DOM-XSS vulnerabilities

In addition to the general measures described on the DOM-based vulnerabilities page, you should avoid allowing data from any untrusted source to be dynamically written to the HTML document.

In this section, we'll explain reflected cross-site scripting, describe the impact of reflected XSS attacks, and spell out how to find reflected XSS vulnerabilities.

What is reflected cross-site scripting?

Reflected cross-site scripting (or XSS) arises when an application receives data in an HTTP request and includes that data within the immediate response in an unsafe way.

Suppose a website has a search function which receives the user-supplied search term in a URL parameter:

https://insecure-website.com/search?term=gift

The application echoes the supplied search term in the response to this URL:

<p>You searched for: gift</p>

Burp Suite Alternative Open Source

Assuming the application doesn't perform any other processing of the data, an attacker can construct an attack like this:

Burp Suite Alternative Open Source Download

https://insecure-website.com/search?term=<script>/*+Bad+stuff+here...+*/</script>

Burp Suite Alternative Open Source Free

This URL results in the following response:

<p>You searched for: <script>/* Bad stuff here... */</script></p>

Burp Suite Tutorial

If another user of the application requests the attacker's URL, then the script supplied by the attacker will execute in the victim user's browser, in the context of their session with the application.

LABReflected XSS into HTML context with nothing encoded

Impact of reflected XSS attacks

If an attacker can control a script that is executed in the victim's browser, then they can typically fully compromise that user. Amongst other things, the attacker can:

  • Perform any action within the application that the user can perform.
  • View any information that the user is able to view.
  • Modify any information that the user is able to modify.
  • Initiate interactions with other application users, including malicious attacks, that will appear to originate from the initial victim user.

There are various means by which an attacker might induce a victim user to make a request that they control, to deliver a reflected XSS attack. These include placing links on a website controlled by the attacker, or on another website that allows content to be generated, or by sending a link in an email, tweet or other message. The attack could be targeted directly against a known user, or could an indiscriminate attack against any users of the application:

Burp Suite Tools

The need for an external delivery mechanism for the attack means that the impact of reflected XSS is generally less severe than stored XSS, where a self-contained attack can be delivered within the vulnerable application itself.

Read more

Exploiting cross-site scripting vulnerabilities

Reflected XSS in different contexts

There are many different varieties of reflected cross-site scripting. The location of the reflected data within the application's response determines what type of payload is required to exploit it and might also affect the impact of the vulnerability.

What Is Burp Suite

In addition, if the application performs any validation or other processing on the submitted data before it is reflected, this will generally affect what kind of XSS payload is needed.

How to find and test for reflected XSS vulnerabilities

The vast majority of reflected cross-site scripting vulnerabilities can be found quickly and reliably using Burp Suite's web vulnerability scanner.

Testing for reflected XSS vulnerabilities manually involves the following steps:

  • Test every entry point. Test separately every entry point for data within the application's HTTP requests. This includes parameters or other data within the URL query string and message body, and the URL file path. It also includes HTTP headers, although XSS-like behavior that can only be triggered via certain HTTP headers may not be exploitable in practice.
  • Submit random alphanumeric values. For each entry point, submit a unique random value and determine whether the value is reflected in the response. The value should be designed to survive most input validation, so needs to be fairly short and contain only alphanumeric characters. But it needs to be long enough to make accidental matches within the response highly unlikely. A random alphanumeric value of around 8 characters is normally ideal. You can use Burp Intruder's number payloads [https://portswigger.net/burp/documentation/desktop/tools/intruder/payloads/types#numbers] with randomly generated hex values to generate suitable random values. And you can use Burp Intruder's grep payloads option to automatically flag responses that contain the submitted value.
  • Determine the reflection context. For each location within the response where the random value is reflected, determine its context. This might be in text between HTML tags, within a tag attribute which might be quoted, within a JavaScript string, etc.
  • Test a candidate payload. Based on the context of the reflection, test an initial candidate XSS payload that will trigger JavaScript execution if it is reflected unmodified within the response. The easiest way to test payloads is to send the request to Burp Repeater, modify the request to insert the candidate payload, issue the request, and then review the response to see if the payload worked. An efficient way to work is to leave the original random value in the request and place the candidate XSS payload before or after it. Then set the random value as the search term in Burp Repeater's response view. Burp will highlight each location where the search term appears, letting you quickly locate the reflection.
  • Test alternative payloads. If the candidate XSS payload was modified by the application, or blocked altogether, then you will need to test alternative payloads and techniques that might deliver a working XSS attack based on the context of the reflection and the type of input validation that is being performed. For more details, see cross-site scripting contexts
  • Test the attack in a browser. Finally, if you succeed in finding a payload that appears to work within Burp Repeater, transfer the attack to a real browser (by pasting the URL into the address bar, or by modifying the request in Burp Proxy's intercept view, and see if the injected JavaScript is indeed executed. Often, it is best to execute some simple JavaScript like alert(document.domain) which will trigger a visible popup within the browser if the attack succeeds.

Common questions about reflected cross-site scripting

What is the difference between reflected XSS and stored XSS? Reflected XSS arises when an application takes some input from an HTTP request and embeds that input into the immediate response in an unsafe way. With stored XSS, the application instead stores the input and embeds it into a later response in an unsafe way.

Burp suite alternative open source version

What is the difference between reflected XSS and self-XSS? Self-XSS involves similar application behavior to regular reflected XSS, however it cannot be triggered in normal ways via a crafted URL or a cross-domain request. Instead, the vulnerability is only triggered if the victim themselves submits the XSS payload from their browser. Delivering a self-XSS attack normally involves socially engineering the victim to paste some attacker-supplied input into their browser. As such, it is normally considered to be a lame, low-impact issue.

Comments are closed.