{"id":1105,"date":"2018-11-27T17:10:19","date_gmt":"2018-11-27T16:10:19","guid":{"rendered":"http:\/\/www.floyd.ch\/?p=1105"},"modified":"2022-02-09T11:35:07","modified_gmt":"2022-02-09T10:35:07","slug":"python-sender","status":"publish","type":"post","link":"https:\/\/www.floyd.ch\/?p=1105","title":{"rendered":"Python Sender"},"content":{"rendered":"

\ufeff<\/span>Last week I played my first Capture The Flag (CTF) where I really tried solving the challenges for a couple of hours. It was a regular jeopardy style CTF with binaries, web applications and other server ports. I don’t think CTFs are going to be my favourite hobby, as pentesting is similar but just a little bit more real life. However, CTFs are very nice for people who want to get into IT security, so I wanted to help a little bit in the team I joined. This particular CTF by Kaspersky really annoyed me though, as the servers were very often offline (HTTP 500 errors). Moreover, some challenges allowed easy Remote Command Execution (RCE)<\/a> and I guess some teams took the chance to prevent other teams from scoring flags. As I just said I’m not very experienced with CTFs, maybe that’s how it’s supposed to be, but for me that’s silly. Anyway, this post is about something more positive: A Python script to play CTFs, but can also be used during pentests. For those who play CTFs very often, it’s probably better to use a full library such as pwntools<\/a>, but if you just want a small script where you can delete whatever you don’t need and go with the POC||GTFO flow, you’ve come to the right place.<\/p>\n

I think two of the mostly presented CTF challenges often look the same. You either get a URL to a challenge website and you have to do some HTTP magic or you get something like “nc www.example.org 1337” where you are supposed to talk to a server with netcat. Now both challenges usually use TCP\/IP and maybe TLS. The website obviously uses HTTP(S) on top of that. So very often you find yourself sending a lot of HTTP requests or a lot of TCP packets to a certain port. Pentests also require the same sometimes.<\/p>\n

To make sure we don’t have to fight if Python 2.7 is better than Python 3.6, the script I wrote works on both versions. But even then, people might argue that python’s urllib or urllib2 is sufficient or that they rather use the non-standard requests library. And others will simply say that only asynchronous network IO is really fast enough, so they prefer to use Python Twisted (or treq). However, I got all of these cases covered in the script.<\/p>\n

The script allows arbitrary socket and HTTP(S) connections via:<\/p>\n