CTF WriteUp: 33C3/list0r

CTF WriteUp: 33C3 CTF 2016 / list0r / web / 400 points

We are presented with a basic Bootstrap/PHP CTF page. It allows to create TODO lists and also to set your own profile. The interesting part here is that in the profile you can give a link to a picture which the server will then fetch. This will be useful later on. First thing we notice is that the pages are of the form:

This allows for a classic PHP attack to leak the source by running the following query

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Perf tool examples

I am a big fan of the linux perf (perf events, perf tools) tool. It has already helped me several times debugging problems or solving performance bottlenecks.

Unfortunately, documentation is rather sparse about it. As such, I created a perf-examples repository that contains small example programs that show how certain perf features can help to find problems.

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CTF WriteUp: 0CTF/Monkey

CTF WriteUp: 0CTF 2016 / Monkey / web / 4 points

We are presented with a simple page that allows us to submit a URL which some monkey will browse for two minutes. In addition, the page says that we can find the flag at The challenge page also asks what the same-origin policy is. Let’s start by answering that question.

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Static Site Hosting with Github Pages and Cloudflare

How I bootstrapped this blog and how you can do it, too. Let’s assume you want to setup static hosting on example.com:

  1. Register your domain with the registrar of your choice.
  2. Sign in/up for Cloudflare with your domain.
  3. Replace the DNS servers of your registrar with the ones you get from Cloudflare.
  4. In the Cloudflare dashboard under DNS add two entries:
    • CNAME example.com yourusername.github.io
    • CNAME www yourusername.github.io

    Make sure that you click the Cloudflare icon for both of these entries to turn them on.

  5. Get started with Github pages as described on this page.
  6. Add an empty file called CNAME containing example.com to your repository.
  7. Push.
  8. Profit!

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Hello World

Welcome to my blog and home page!

A place where I collect all my stuff and probably blog from time to time.

This my first entry and I am still trying out stuff.