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Questions tagged [html]

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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49 views

Can a corrupted image/video become a XSS vector?

Let's suppose that I allow users to upload an image or a video. Obviously, I rename it on the server side. Can an attacker use it to conduct an XSS attack? I show images in this way: <img src="...
23
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12answers
12k views

Is there a way to hide HTML source code yet keeping it effective?

I have a website with a client-side HTML contact form created manually (not as output of an HTML constructor like PHP): <form action="mailto:someone@example.com"> Email Adress:<br> ...
3
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0answers
68 views

Is this XSS filter for HTML comments safe?

HTML comments can be notoriously tricky from an XSS standpoint, and the standard recommendation seems to be to never put untrusted user data in them. But shouldn't it be possible to strip out a few ...
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1answer
82 views

Ingesting markup from WYSIWYG text editors

Maybe I'm missing something obvious here... The development landscape is littered with client-side WYSIWYG text editors (for example, TinyMCE), all of which seem to want to send raw HTML back to my ...
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1answer
61 views

Exposing a version number through the assets urls

I just received a blackbox pentesting report where the security company recommended to hide the version number from the page (be it returned to the user as a text or used as a cache-buster in the css/...
2
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1answer
68 views

Can a javascript on parent page log keystrokes inside an iframe?

I am trying to analyze the possibility of accessing keystrokes from an iframe using a javascript running on the parent page. The potential attack which I am looking to verify is Cross Frame Scripting. ...
0
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1answer
45 views

Does A6 - Security Misconfiguration be reported for embedded JS? [duplicate]

We have a HTML file with a minified JSlibrary pasted inside with the license header and version number. Our client reported that it's a security risk (https://www.owasp.org/index.php/Top_10-2017_A6-...
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2answers
81 views

Understanding POST based XSS

I have been trying to learn about XSS, more specifically, POST based XSS. But I am unsure if I actually understand how POST based XSS works. With a GET, you can do XSS with the URL parameters, but to ...
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2answers
73 views

Is there any good reason to move files outside webserver document root?

Let's say I create a website (with apache for example) and my php pages get some sensitive information from a file on disk (a .ini file, a SQLite db or whatever). I thought two ways to prevent users ...
1
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1answer
286 views

How can Instagram cause Chrome to attempt to login and show me my username when I'm using incognito mode?

When I reach Instagram user pages while in Incognito mode, Chrome pops up a window with my non-incognito username asking whether or not to sign in. See screenshot below. Although I assume Chrome ...
2
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1answer
90 views

Is <meta> http-equiv secure?

I'd like to redirect a visitor to the login page if he's not authenticated and she/he wants to access a protected page. I can handle this via the backend code, but it's easier to make it using HTML. ...
-1
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1answer
66 views

Javascript with HTML for CSRF [closed]

<html> <h1>POC CSRF</h1> <form> Enter bWAPP Password:<input type="password" id="password" placeholder="password"> </form> ...
3
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1answer
164 views

Safe user input HTML in 2019

(I know this topic has been discussed a lot in the past, and I've read a lot of threads here as well as OWASP, but have additional questions including the specific CSP listed below.) We want to allow ...
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1answer
193 views

java script in link href=“javascript:alert(1)”

In an app I am testing they allow to input a domain name, store it, and when they print it on the browser they concatenate "http://" at the beginning of the domain. So, if you input "google.com", then ...
0
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1answer
221 views

Is security by obscurity / obfuscation a valid option, or do the crawlers have JavaScript enabled?

I'm creating a new website, so I am thinking about how to protect my email address and phone number against crawlers, I actually mean email harvesters (most of which I suppose don't have JavaScript ...
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4answers
143 views

can XSS attacks be nullified by prepending a backward slash to all external links?

In my website I noticed my developers had set it up so certain form data was past from the URL to the content of the website. E.G ?email="email" The obvious vulnerability means that I can put ?email=...
-2
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1answer
106 views

Inspect Element Prevention?

I was just actually wondering if there is a permanent way of preventing or disabling inspect element on client-side? Assuming with inspect element you could change values in hidden forms as well as ...
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0answers
40 views

Security Measures for HTML Anchor Download Feature

Do I need to explore security measures for the native HTML <a download> feature? What are some ways that this feature opens my website up to potential threats, and how should I mitigate those ...
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2answers
101 views

Cross Site Scripting href=/\evil

I've seen <base href=/\evil> and <base href=//0> as a vector to use XSS. Could someone make an example using these vectors and explain me if "/\" is the same as http:// or has some ...
1
vote
1answer
115 views

Is it possible to exploit XSS by replacing image data for img tag [duplicate]

If I have HTML page served over https with image loaded over http (image from other domain): <img src="http://some-image.png"/> so it's possible to inject any data to browser as image by using ...
0
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1answer
70 views

Is this CORS exploitable?

So i was able to upload a html file on a server i'm allowed to test. The file is uploaded on a subdomain of the main server. Knowing that they allow CORS for anything.domain.com, is it possible to ...
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0answers
30 views

is xss possible without these chars? [duplicate]

I'm wondering if xss is possible without these chars disallowed/filtered text: < > ! @ # $ % ^ & * : ? = ( ) I'm able to break out of a style attribute of an element by introducing an ending ...
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1answer
132 views

Unknown code on my website comments [closed]

During the last few weeks, I often find on my website these "Comment": {"name":"BryantFlogy","email":"cgorillamail@gmail.com","message":"Hi, htmlkurss.xyz \r\n \r\nI&#39;ve been visiting your ...
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2answers
607 views

How to exploit XSS vulnerability through an iframe

Recently, I found a stored cross site scripting vulnerability in a rather large website, but I am not sure if it is dangerous or worth reporting. On this website, there is a resource section that is ...
1
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1answer
297 views

Bypass a simple XSS filter that only looks at <

Say, I have a page where the input from the user is taken and is passed through a simple client-side XSS filter. That filter only replaces < characters with ''. in = in.replace(/[<]/g, ''); ...
2
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0answers
67 views

Persistent HTML form data across sessions

I'm currently testing an application which appears to have a somewhat persistent HTML form data storage, yet I don't understand how. UserA logs in Fills form with custom data Logs out before sending ...
43
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8answers
8k views

Is it ever safe to open a suspicious HTML file (e.g. email attachment)?

If I receive an email that has an attachment called something like safe-link.html would it ever be safe to open this file? Clearly, HTML files may have malicious scripts embedded that could run when ...
0
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0answers
54 views

Embeddable 3rd party web tools security against stealing the key

We are building a website and we are using plenty of third-party tools that basically give you an HTML script tag and ask you to place it into your index.html. A few examples of such tools are: ...
0
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4answers
345 views

Is XSS and HTML injection the same?

When doing a XSS, we usually put the JavaScript code between the <script> tags. I have noticed that HTML injections are very similar because you are doing almost the same thing, but using ...
0
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1answer
29 views

How to filter HTML Event in Native PHP7

i want to creating xss filter for my own project, this is for html event filtering preg_replace("/ on\w+='[^']*'/i", '', preg_replace('/ on\w+="[^"]*"/i', '', $framed)); but considering to more ...
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2answers
223 views

Can a hacker determine what version of WordPress and PHP a site is using?

Can a hacker determine what version of WordPress and PHP a site is using? Assume this info is not available by View Source.
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1answer
354 views

What would be an example of an attack that exploits escape characters?

As far as I know escape characters are characters which change the meaning of the following character. In HTML for example the & is an escape character that declares the beginning of an entity ...
1
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5answers
104 views

How to stop a request for an external image from exposing my IP to the server hosting the image?

Suppose I have a server A, and that there is a website W hosted on A. The HTML of W contains: <img src=https://www.domainD.com/testT.jpg> Then I have a computer C, that accesses W. Will ...
1
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1answer
609 views

Does CSP block javascript in <a href> tags?

I recently discovered that its possible to run javascript from an <a> tag like this <a href="javascript:alert('test')"> and this gets run on the current page when clicked. It also seems ...
2
votes
2answers
340 views

Vulnerability in using `input type=“text”` for website password other than shoulder surfing

I found a website that uses the plain text field as a password input form. <input type = "text" autocomplete= off ...> I understand shoulder surfing is one vulnerability but are there other ...
3
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1answer
138 views

How can user send malware code via input=file

After the file is uploaded via input=file it is converted to b64 standard. But what is the exact path the file is going through and where in javascript code we can catch that uploaded file. And if I ...
-2
votes
1answer
85 views

How to check hosted content for fraud?

I am a developer at a company that makes landing page software. Users can register and build their own page and publish it. We will provide them a subdomain on our whitelabel domain: test-link....
0
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4answers
823 views

XSS payload shorter than 20 character

For an university project I have to perform an analysis on a web application to find out XSS vulnerabilities. After this I have to report and create automatic test to prove vulnerabilities that I have ...
1
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1answer
44 views

Site inaccessible with Cookies turned off in browser [closed]

Whenever I access my website with cookies turned off in browser, it redirects me to a google support page that informs me to allow cookies. My website is simple (a blog) HTML and CSS and I store nor ...
3
votes
1answer
238 views

How do I make safe login-emails? (GET/POST) [duplicate]

Vision I envision a login/signup-system, where the user enters his/her email, and receives an email with a link to sign in. The user clicks the link, and is automatically signed in (confirming the ...
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0answers
36 views

security of <link rel=“canonical”>

today I was a bit surprised to see a <link rel="canonical">-Tag in action: I was reading this news article on my android phone and wanted to share it: https://www.golem.de/news/hyundai-nexo-...
0
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2answers
256 views

XSS alert not working with concatenated string

I've noticed that the following Stored XSS does not execute, whereas in the JS console it works: <img src=0 onerror=alert(document.domain+": "+Date.now())> This doesn't prompt an alert box. ...
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0answers
217 views

Understanding XSS

So, I am trying to understand how XSS works and I gathered some information online and crafted the code. Following is the snippet. When I enter some value in the text field and submit, the script ...
0
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1answer
83 views

Can I name a file .pl and run it as html on server? [closed]

I want to know if it is possible to name file .file.pl and run it as HTML. I want this to exploit CORS misconfiguration of a website which only checks origin header for .realwebsite.pl and we can add ...
0
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3answers
84 views

Determine All Possible Fields in HTML Form

Is it possible to determine, from the client-side, all the valid fields for a given backend form processor, even if they are excluded from the webpage containing the form? For example: Assume a ...
0
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1answer
40 views

What is the benefit of combining a form with php processing script in a single page using isset

I would like to know the benefits of using a single page with both the PHP processing script and the HTML form using isset() as opposed to simply using form action with method POST on one page to call ...
3
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3answers
153 views

Relative paths in web applications

I'm currently reading a security audit of a web application where they rank relative paths in a web application as a security risk. e.g.: <a href=../contact.html>Contact</a> I found ...
0
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1answer
426 views

Allow ModSecurity to pass specific HTML tags?

I have a web-server running a Perl site, and I have a WAF (ModSecurity) running. The website has a form. When submitted the request contain HTML tags like so: <br+/> <div+style="border:none;...
1
vote
1answer
468 views

How to store an user access token on a third party site in the front end

I am working on a wordpress plugin that provides a comment thread system kind of like disqus (but different). In order to login (to post comments) the workflow is like this : User clicks on log-in ...
64
votes
2answers
8k views

Are EU cookie consent forms safe? [closed]

Does the EU consent form system pose a new security risk? Today we have to click OK on about 20 cookie consent forms every week, where previously we could mostly dismiss internet forms as being ...