writeup – devel0pment.de

6. September 20206. September 2020

ALLES! CTF 2020 – Actual ASLR 1/2

The ALLES! CTF (ctftime.org) took place from 04/09/2020, 16:00 UTC to 06/09/2020, 19:00 UTC with a variety of interesting, creative challenges.

Within this article I want to share my writeup on the two challenges Actual ASLR 1 and 2, which were authored by LiveOverflow. What I especially liked about the challenge(s) is that you could make progression step by step even getting a first flag on the way to a full shell, which grants access to the second flag.

The article is divided into the following sections:

→Actual ASLR 1
    – Binary
    – Random Algorithm
    – Reimplementation In Python
    – First Flag

→Actual ASLR 2
    – Custom Heap
    – Vulnerability
    – Heap Leak
    – Image Base Leak
    – Overwriting Function Pointer
    – Final Exploit

1. January 20201. January 2020

HACKvent19 writeup

This year’s HACKvent was hosted on the brand new Hacking-Lab 2.0 plattform. Each day from the 1st of december until the 24th a new challenge is published raising in difficulty. The flag format changed from HV18-xxxx-xxxx-xxxx-xxxx-xxxx to HV19{...}. After all I managed to solve all 28 challenges 🙂

	Hidden
HV19.H1 Hidden One HV19.H2 Hidden Two HV19.H3 Hidden Three HV19.H4 Hidden Four
	Easy
HV19.01 censored HV19.02 Triangulation HV19.03 Hodor, Hodor, Hodor HV19.04 password policy circumvention HV19.05 Santa Parcel Tracking HV19.06 bacon and eggs HV19.07 Santa Rider
	Medium
HV19.08 SmileNcryptor 4.0 HV19.09 Santas Quick Response 3.0 HV19.10 Guess what HV19.11 Frolicsome Santa Jokes API HV19.12 back to basic HV19.13 TrieMe HV19.14 Achtung das Flag
	Hard
HV19.15 Santa’s Workshop HV19.16 B0rked Calculator HV19.17 Unicode Portal HV19.18 Dance with me HV19.19 U+1F385 HV19.20 i want to play a game HV19.21 Happy Christmas 256
	Leet
HV19.22 The command … is lost HV19.23 Internet Data Archive HV19.24 ham radio

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1. July 20191. July 2019

Google CTF 2019 (Quals) – Quantum Key Distribution

This years online qualification for the Google Capture The Flag finals (ctftime.org) ran from 22/06/2019, 00:01 UTC to 23/06/2019 23:59 UTC.

As last year, there were plenty of diversified challenges, which were worked out very well.

I tried to take at least a look at as much challenges as possible and solved the challenge Quantum Key Distribution, which was relatively easy based on the amounts of solves. Within this article I want to share my writeup on this challenge.

The writeup is divided into the following sections:

Challenge description
BB84 protocol
Source code
Outlined process
Solution

12. June 201912. June 2019

Hacky Easter 2019 writeup

As every year hacking-lab.com carried out the annual Hacky Easter event with 27 challenges. As usual the variety of the challenges was awesome. I actually got full score this year 🙂 Many thanks to daubsi, who gave me a nudge once in a while on the last challenges (you can find his writeup here).

	Easy
01 Twisted 02 Just Watch 03 Sloppy Encryption 04 Disco 2 05 Call for Papers 06 Dots 07 Shell we Argument 08 Modern Art 09 rorriM rorriM
	Medium
10 Stackunderflow 11 Memeory 2.0 12 Decrypt0r 13 Symphony in HEX 14 White Box 15 Seen in Steem 16 Every-Thing 17 New Egg Design 18 Egg Storage
	Hard
19 CoUmpact DiAsc 20 Scrambled Egg 21 The Hunt: Misty Jungle 22 The Hunt: Muddy Quagmire 23 The Maze 24 CAPTEG
	Hidden
25 Hidden Egg #1 26 Hidden Egg #2 27 Hidden Egg #3

31. March 201931. March 2019

VolgaCTF 2019 Qualifier – Blind

The VolgaCTF 2019 Qualifier (ctftime.org) took place from 29/03/2019, 15:00 UTC to 31/03/2019 15:00 UTC.

There has been a really interesting RSA crypto challenge called Blind, which I would like to share with you in this writeup.

The article is divided into the following sections:

→ Challenge description
→ What does the script do?
→ Blind RSA Signature
→ Retrieving the Flag

Continue reading “VolgaCTF 2019 Qualifier – Blind”

3. February 20193. February 2019

nullcon HackIM 2019 – babypwn

The nullcon HackIM 2019 CTF (ctftime.org) ran from 01/02/2019, 16:30 UTC to 03/02/2019 04:30 UTC.

I did the pwn challenge babypwn, which was really fun to do. The following article contains my writeup being divided into the following sections:

→ Challenge description
→ Security mechanisms and disassembly
→ Signedness vulnerabilitiy
→ Format string vulnerabilitiy
→ Final exploit

Continue reading “nullcon HackIM 2019 – babypwn”

1. January 20194. January 2019

HACKvent18 writeup

For the sixth time in a row now hacking-lab.com carried out the annual HACKvent. Each day from the 1st of december until the 24th a new challenge is published. I would have loved to spend more time on it, but time is a rare resource especially on the days before christmas 😉 After all I managed to solve 21 of 24 tasks:

	Easy
Day 01: Just Another Bar Code Day 02: Me Day 03: Catch me Day 04: pirating like in the 90ies Day 05: OSINT 1 Day 06: Mondrian Day 07: flappy.pl
	Medium
Day 08: Advent Snail Day 09: fake xmass balls Day 10: >_ Run, Node, Run Day 11: Crypt-o-Math 3.0 Day 12: SmartWishList Day 13: flappy’s revenge Day 14: power in the shell
	Hard
Day 15: Watch Me Day 16: Pay 100 Bitcoins Day 17: Faster KEy Exchange Day 18: Be Evil Day 19: PromoCode Day 20: I want to play a game Day 21: muffinCTF (Day 1) Day 22: muffinCTF (Day 2) Day 23: muffinCTF (Day 3)
	Final
Day 24: Take the red pill, take the blue pill

Continue reading “HACKvent18 writeup”

22. May 2018

Hacky Easter 2018 writeup

As every year hacking-lab.com carried out the annual Hacky Easter event with 27 challenges. I could not spend as much time as I would have liked to on solving the challenges, but after all I managed to collect 25 of the 27 eggs and focused on this writeup.

	Easy
01 Prison Break 02 Babylon 03 Pony Coder 04 Memeory 05 Sloppy & Paste (mobile) 06 Cooking for Hackers 07 Jigsaw 08 Disco Egg 09 Dial Trial (mobile)
	Medium
10 Level Two 11 De Egg you must (not solved) 12 Patience (mobile) 13 Sagittarius… 14 Same same… 15 Manila greetings 16 git cloak –hard 17 Space Invaders 18 Egg Factory
	Hard
19 Virtual Hen 20 Artist: No Name Yet (not solved) 21 Hot Dog 22 Block Jane 23 Rapbid Learning 24 ELF
	Hidden
25 Hidden Egg #1 26 Hidden Egg #2 27 Hidden Egg #3

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21. May 201822. May 2018

RCTF 2018 – writeup cpushop

The RCTF 2018 (ctftime.org) ran from 19/05/2018, 09:00 UTC to 21/05/2018 08:59 UTC.

I wrote the following writeup for the crypto challenge cpushop.

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21. March 20183. January 2019

angstromCTF 2018 – writeup hellcode

The angstromCTF 2018 (ctftime.org) ran from 16/03/2018, 20:00 UTC to 23/03/2018 00:00 UTC.

As the description on ctftime.org states, the ctf is primarily geared towards high school students but with a very wide range of challenge difficulty.

There have been a lot of interesting challenges which have been fun to do. I decided to make a writeup for the pwn challenge hellcode.

Continue reading “angstromCTF 2018 – writeup hellcode”