cheatsheets | Cheat sheets provided by encore.dev | Learning library

I've started playing with XSS to better improve my security posture at work. I've been able to successfully exploit a reflected XSS attack using a redirected POST form, but I can't seem to remove the extraneous characters displayed on the page.

I've checked:

XSS: Character showing in DOM

https://security.stackexchange.com/questions/207282/xss-character-showing-in-dom?newreg=61e9890d94d34d0c8818158ba541b117

How to load javascript on another webpage through XSS?

But none of the suggestions seem to work for me.

My exploit is a basic form, exploiting a PHP server side script I've configured echoing $_POST['username'] into the value attribute:

What is the meaning of context in the passage below?

The first rule is to deny all - don't put untrusted data into your HTML document unless it is within one of the slots defined in Rule #1 through Rule #5. The reason for Rule #0 is that there are so many strange contexts within HTML that the list of encoding rules gets very complicated. We can't think of any good reason to put untrusted data in these contexts. This includes "nested contexts" like a URL inside a JavaScript -- the encoding rules for those locations are tricky and dangerous.

If you insist on putting untrusted data into nested contexts, please do a lot of cross-browser testing and let us know what you find out.

This passage is taken from Cross Site Scripting Prevention - OWASP Cheat Sheet Series.At there,you can find rule #0 through rule #5.

Reading this XSS cheat sheet, I noticed a special usage I have never seen:

I have a pandas DataFrame similar to this:

I am trying to create a local environment for the ML Studio using the Python SDK, following this official cheatsheet. The result should be a conda-like environment that can be used for local testing. However, I am running into an error when importing the Numpy package with the add_conda_package() method of the CondaDependencies() class. Where I've tried not specifying, as well as specifying package versions, like: add_conda_package('numpy') or add_conda_package('numpy=1.21.2'), but it does not seem to make a difference.

Numpy's error message is extensive, and I've tried many of the suggestions, without success nonetheless. I'm grateful for any tips on what might resolve my issues!

From the OWASP's website https://cheatsheetseries.owasp.org/cheatsheets/Content_Security_Policy_Cheat_Sheet.html:

Send a Content-Security-Policy HTTP response header from your web server.

Content-Security-Policy: ...

Using a header is the preferred way and supports the full CSP feature set. Send it in all HTTP responses, not just the index page.

I don't understand how that could be true as it is possible to set the Content-Security-Policy by using a meta tag in the HTML. I also don't see how the policy can apply to anything else but HTML pages.

Does anyone have idea why that statement above was made and if it is safe to only send HTTP header Content-Security-Policy for text/html responses?

By the way, the policy is too big and I would like to sent as fewer bytes as possible.

Problem

I'm using Apache FOP to produce a PDF from an XML and XSL file. The XML file is downloaded from an external site, not generated by me, so any manipulation of it would need to be scripted. It contains tags that contain anchor HTML tags inside of them intended to be named hyperlinks, but the xsl:value-of tag seems to somehow strip any functionality of anchor tags inside of the string itself and leaves the PDF report to have the display text of the anchor, but not the hyperlink, leading to "click here" labels that aren't actually clickable with no way to tell what the URL was supposed to be because the href tag is completely gone.

XML (snippet)

I'm trying to build a query with Arel with Rails 6 API. I've found this howto that looks great but I'm getting errors. Though the examples were created many years ago and based on few searches, things looks the same. I have a simple module class:

I am wondering how I can create a docs site like create-react-app or react typescript cheatsheets. I am imaging they are using the same package or setup, I just want to know what they are using. Apologies if the answer is too obvious!