HTML (HyperText Markup Language) is a language used to create web pages using tags inline with the content to indicate to browsers how to display that content, using the tags to interpret formatting, images, scripts and other content.

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24 views

taking input from webform and piping into bash password prompt

I've been wanting to create a simple web application that would allow me to view certain text files that I've encryped with GnuPG residing on my webserver through any browser remotely. I've figured ...
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0answers
27 views

How to check if /run timeout /T 5 remote command execution worked in page html?

I was scanning a website using Zed Attack Proxy, when I found it is vulnerable to remote command execution, specifically timeout with the Referer header (shown in the request below). I have no idea ...
9
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2answers
78 views

Best practices when forwarding an email or copy / pasting from confidential information sources?

I get asked this a lot from older people, or for legal matters. They want to forward an email message they've received to another party, while removing any identifying information from the first party ...
2
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2answers
74 views

How do I prevent extra javascript from being added into HTML kiosk in public space?

I'm planning a project which is to be PCI compliant, but I am stuck on a particular vulnerability and I can't think of a way to protect against it. The scenario is that there is a kiosk installed in ...
2
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1answer
193 views

HTML iframe security exploit

Can somebody explain if there's something malicious in this HTML, The width and height of the iframe ares set to 1 and it's out of the view with top: -100px; statement. I believe it takes some some ...
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0answers
20 views

Sites to test login through jmeter [duplicate]

Im having a hard time looking for a site with a login system that can be probed with firebug, the POST request password specifically, i was just wondering if anyone here knows one or two sites that ...
3
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1answer
23 views

XSS Injection invalidate meta redirection tag

When injecting into the url part of an HTML META redirect like this: <meta http-equiv='refresh' content='0;URL=$URL' where $URL (note the missing quotes) is the part I can inject, is there any ...
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0answers
95 views

What vulnerability is this malicious document attempting to exploit

CLARIFICATION: I changed the title as people were interpreting this as a request to help understand the code. I explain what the code is doing below (critiques on this analysis are welcome.) I am ...
2
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2answers
555 views

If using htmlentities or htmlspecialchars functions is enough for block XSS attack

I know this question was discussed on net various times. and people give some example how to bypass these functions through passing some code. But here one issue, All example of ...
2
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4answers
1k views

HTML password fields

Imagine you are in a HTML page which offers you the password change service. Some websites bring the previous password in a password field, which you can't read. Is it possible to retrieve the ...
2
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1answer
66 views

How to make the most secure text editor in Django?

As a follow up to this question, I'm wondering what is the most secure way (using either markup or markdown) to allow users to format their inputs and upload images in a Django app? I'm not asking ...
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3answers
131 views

Can these html tags and attribs make my site vulnerable?

I am developing a social website and want to allow user ONLY these html tags and attributes in their posts: tags: <img>, <b>, <strong>, <blockquote>, <a> attributes: ...
5
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3answers
86 views

Input validation: how to do it if I must accept HTML as part of my input?

I'm writing a service which receives FHIR data and it stores it. FHIR is an HL7 healthcare information standard format which contains HTML by definition, embedded into a JSON or XML, (to ensure ...
2
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1answer
163 views

302 redirect and the body on the page (you are redirected to …)

I have page which take URL on query and string and it. Then, you get redirected using 302 to another page, and the response of the page contains HTML code and the redirect header. Like this: ...
0
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1answer
82 views

Is it possible to get a flash src after a redirect or an element inside an embed/object/iframe tag (cross-domain)?

The URL example.com/auth will automatically redirect the user (HTTP 302) to example.com/signed_in.SWF?token=SENSITIVE. Is it possible for an attacker to steal the token, using javascript or flash, in ...
1
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3answers
47 views

What is a typical defense mechanism/setup against flooding back-end sql calls?

I'm interested in figuring out what is a typical scenario of preventing the following attack scenario: Back-end has as SQL server. Front end a simple "Hello World" HTML that passes an input (say user ...
8
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2answers
855 views

How to launch XSS code from an INPUT HTML tag upon page load?

Say I have the a website with the following code on it: <input type="text" id="search-text" name="query" value="?" /> Double quotes aren't escaped so I can break out of the value attribute, ...
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3answers
136 views

The purpose of escaping html entities

By security principles, we are often taught to sanitize input fields for characters such as & or ' so that they cannot be used for SQL injections etc. However, now I have an issue: I really need ...
3
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2answers
81 views

Can 3rd party JavaScript libraries access the http headers of the hosting html page

So, I have website, it uses a cookie stored in the http header of the downloaded html document to maintain the session while the end user is logged on and accessing there 'secure' data. This webpage ...
39
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4answers
6k views

Have computer criminals been known to exploit easily-edited websites like Wikipedia to embed malicious scripts?

When I was reading a page on Wikipedia several months ago (December 2014) I saw what looked like a pop-up window from BT, but I soon realized that when I closed the page the pop-up disappeared. I then ...
2
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1answer
250 views

XSS in Content-Disposition

Lets assume i have found a xss on site example.com, now to trigger an XSS, i use the following URL: https://example.com/a.php?v=%22%3E%3Cimg%20src=x Which results in following response: HTTP/1.1 ...
0
votes
2answers
90 views

Random characters and letters form obsfuscation

I know that this question has been asked many times, but would JavaScript encryption work if I just added 100 random numbers and letters to the password? That would be hard to reverse engineer, ...
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2answers
70 views

How to ensure website from hackers and more? [closed]

I'm really new to security in Websites, for example... So can someone give me somewhere to start please? Sorry if it's not the right place to ask... :|
2
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1answer
100 views

What does this attack string do? How do I mitigate it?

Today I decided to run the apache-scalp script and it found a few issues. One was ranked as Impact 5, and I'd like to know if someone could explain what this does, and how to disable it? The request ...
3
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3answers
486 views

Why did I see an insecure browser warning on my page?

Originally I was under the impression that a particular page on a site I visited was showing an insecure content warning in my browsers due to the tags on the page having plan http href attributes. ...
3
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3answers
182 views

Any Security Risks for using mailto:?

I use a PHP script which performs a database search and when no result are found, user is presented with a mailto link with this format mailto:example@test.com?subject=SEARCHED_QUERY_HERE The ...
2
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1answer
277 views

Exploiting mailto links

Supposing that the user has the power to include any content after mailto: snippet, are there any possible security vulnerabilities? Example: The user says their email address is foo. The link on ...
5
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1answer
231 views

How do I securely embed an <img> tag using a user-given URL?

If I hypothetically wanted to allow users to use an avatar from an arbitrary URL like this: <img class="avatar" src="{user input}" /> There are many problems that I can think about: There ...
5
votes
1answer
276 views

Safe to render data directly to DOM from localStorage? XSS attack possible?

I read that localstorage is susceptible to XSS attacks. I currently store JSON Web Token (JWT) in localstorage, and I access and display data about the user through localstorage: var localstore = ...
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2answers
273 views

How to prevent user from removing disabled attribute and manually editing role?

So I am supposing the user has general knowledge of HTML. I have this code: <select name="role" id="role" disabled> <option value="Admin">Admin</option> <option ...
3
votes
2answers
741 views

Set the max length for input

Suppose I have a form, and one of this form inputs I set the max length to 15: <input type="text" name="username" maxlength="15"> Now the attacker wants to override this limit, to do that he ...
4
votes
1answer
208 views

What are some useful tags and payloads for HTML injection on CSP-protected sites?

I'm pen-testing a website that fixed most of its XSS vulnerabilities by just adding a Content Security Policy. There are still HTML injections in several places. I've tried to get a ...
21
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2answers
2k views

Does this CSS code expose if a message is read, and how long they have been reading it?

This email analytics company offers an 'engagement metric' that shows how much time someone spends looking at an email, whether the email is printed or deleted. They also claim it works in pretty ...
3
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1answer
315 views

How can I successfully perform an xss attack on a dummy website? [closed]

in my security course, we were told to practice an xss attack using firefox on this website; http://permalink.co/ No worries, this is a website specifically setup for us to practice ...
3
votes
1answer
123 views

What methods can be used to prevent the browser (IE11 specifically) from storing credentials / autocomplete

Going through Pen Test and it was asked of us to disable auto complete in our CC payment fields. We tried adding autocomplete=off and also tried false on the input filed. A ny suggestions to ...
10
votes
2answers
2k views

How do the Stack Exchange sites protect themselves from XSS? [duplicate]

It seems to me that because Users can post questions and comments in them with HTML markup (possibly <script> tags), Stack Exchange sites would be very exposed to XSS attacks. How do they ...
2
votes
1answer
95 views

Sanitise specific HTML attribute values against XSS

We want to implement a "safe mode" in a Markdown parser called Parsedown. We have a MarkupEscaped option that disables HTML input, but this is not enough. In order to be safe, the parser needs to ...
5
votes
1answer
369 views

Why is a child window allowed to change the location of its parent?

Maybe a silly question. When opening a new tab via target="_blank", the page that loads in that tab is allowed to set a new location in the parent tab using: ...
1
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2answers
372 views

CAPTCHAs: How does simple math in cleartext prove you're human?

I'm intrigued that many sites use seemingly random numbers with a random operator as a security check to validate that you're not a bot. Forgive my ignorance in captcha technology, but what is ...
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1answer
202 views

php execution possibility in img src

I am creating a simple application. There is an option to download a generated image. For that, my PHP code is: <?php if (isset($_GET['img_name'])){ ?> <html> <img src="<?php echo ...
2
votes
2answers
304 views

is it sufficient to convert '(single-quote) to ` &#039; `

Is it sufficient to convert ' to &#039; , > converted to &gt; and < converted to &lt; to avoid xss A bit of context: the payload would be going through the URL and landing in a ...
2
votes
5answers
3k views

Is converting `<` to `&lt;` sufficient to prevent execution of JavaScript from arbitrary HTML?

This is kind of a bar-bet question. An acquaintance of mine has made the claim that, given an arbitrary glob of HTML, it can be completely prevented from executing JavaScript if, before slapping it ...
1
vote
1answer
242 views

Arbitrary code execution by opening a webpage by IE?

I came across this piece of HTML code today: <!doctype html> <html> <meta http-equiv="X-UA-Compatible" content="IE=EmulateIE8" > <head> </head> <body> <SCRIPT ...
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votes
2answers
558 views

What is the best exploit of XSS within 100 characters? [closed]

I found a vulnerable php script on my website. The script allows an user input (textarea), which is not encoded by htmlspecialchars(). Therefore it is possible to add html and javascript code. The ...
5
votes
2answers
794 views

Should every output element be filtered, or just those which contain user-editable data? [duplicate]

I'm combing through a legacy app updating SQL to prevent Injections and XSS vulnerabilities. I know to apply PHP's htmlspecialchars() anything that is directly passed to a script and displayed on a ...
2
votes
1answer
199 views

Is preventing XSS/HTML Injection really this simple?

A colleague suggested to me just to prevent letter characters from occurring immediately after an opening angle bracket as a way to protect against XSS and HTML injection. Obviously, this doesn't ...
1
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3answers
205 views

Make all form inputs safe but allow any type of input including code

Pastebin allow you to (along with plenty of other sites) input code into there forms. I know that this can be a huge security threat if not done properly so I would like to know how they go about ...
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2answers
152 views

How to get the information from the iframe displayed (ClickJack) to the user back to the attacker?

Just for knowledge I want to know how to get the information from the i-frame displayed to the user back to the attacker? Scenario : Suppose You are an attacker and you want to grab the private ...
-3
votes
1answer
99 views

Feedback Form Exploitation possible or not? [closed]

how an attacker can exploit the below provided feedback form in a company website containing the company’s domain? the feedback form does not store data into a database. The server side code only ...
2
votes
1answer
160 views

XSS: alert() not executed on different OS/computer

I've encountered a strange behavior while I was performing a security audit of a web application. Some user controlled inputs were displaying their values, unencoded, into the page that processed the ...