writeup – devel0pment.de

4. February 202326. June 2023

Hack The Box – Response

Ever since I played Hack The Box, I have wanted to create a box myself. As the time went by, I encountered so much cool vulnerabilities and techniques both in real-world engagements and CTFs, which I thought would be fun to put in a box. The result of this is Response.

→ Introduction
→ User (→ bob)
    – Enumeration
    – Server Side Request Forgery
    – Internal Chat Application
    – Cross-Protocol Request Forgery
→ Scanning Script (bob → scryh)
    – Make own HTTPS Server being scanned
    – Setting up own DNS Server
    – Setting up own SMTP Server
    – Directory Traversal
→ Incident Report (scryh → root)
    – Decrypting Meterpreter Session
    – Restoring RSA private key

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24. October 202124. June 2023

ASIS CTF Quals 2021 – ASCII art a a service

The ASIS CTF Quals 2021 (ctftime.org) took place from 22/10/2021, 15:00 UTC to 24/10/2021, 15:00 UTC providing a total amount of 24 challenges.

One of those challenges I really enjoyed was ASCII art as a service. This article contains my writeup for the challenge and is divided into the following sections:

– Challenge Description
– Source Code
– Solution

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13. May 202113. May 2021

Hacky Easter 2021 writeup

HackyEaster was awesome again. From a technical point of view there weren’t too much new things, but the creativity of the provided challenges made it really fun. Including the little teaser challenge there were a total amount of 37 challenges. These challenges were divided into different levels. You could only proceed to the next level, if you have earned enough points in the current level. I really liked that new idea.

1. January 202124. January 2021

HACKvent20 writeup

This year’s HACKvent hosted on competition.hacking-lab.com has been as great as every year.
There was a total amount of 28 awesome challenges with varying difficulties.

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

Continue reading “HACKvent19 writeup”

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”