[New post] picoCTF 2021 speeds and feeds Writeup

Daniel posted: " speeds and feeds is a Reverse Engineering challenge worth 50 points. The description of this challenge is: There is something on my shop network running at nc mercury.picoctf[.]net 16524, but I can't tell what it is. Connecting to the host provi" Respond to this post by replying above this line New post on DMFR SECURITY picoCTF 2021 speeds and feeds Writeup by Daniel speeds and feeds is a Reverse Engineering challenge worth 50 points. The description of this challenge is: There is something on my shop network running at nc mercury.picoctf[.]net 16524, but I can't tell what it is. Connecting to the host provided in the description, I was presented with about 1000 lines of text that looked like this: G17 G21 G40 G90 G64 P0.003 F50 G0Z0.1 G0Z0.1 G0X0.8276Y3.8621 G1Z0.1 G1X0.8276Y-1.9310 G0Z0.1 G0X1.1034Y3.8621 G1Z0.1 G1X1.1034Y-1.9310 ...snip... I had no idea what any of this was, so I Googled one of the strings that were repeating G0Z0.1. This quickly informed me that I was likely looking at G-code, a programming language for CNC machines. Because of overhearing conversations at the Syn Shop, I knew what G-code did and roughly how it worked, and that there is software that will plot G-code out for you. I guessed that the flag will probably be drawn out with this G-code. Searching Google for G-code online, I was able to find an online viewer for G-code scripts at https://ncviewer.com Pasting the G-code into this site yielded the flag: Daniel | October 31, 2021 at 10:00 pm | Tags: CTF, g-code, picoctf, reversing | Categories: CTF | URL: https://wp.me/p8aFuC-2c2 Comment    See all comments    Like Unsubscribe to no longer receive posts from DMFR SECURITY. Change your email settings at Manage Subscriptions. Trouble clicking? Copy and paste this URL into your browser: http://dmfrsecurity.com/2021/10/31/picoctf-2021-speeds-and-feeds-writeup/ Thanks for flying with WordPress.com