Writeups

Category: Fullpwn Solver: lmarschk Flag: HTB{c1_cd_c00k3d_up_1337!} Writeup When scanning the machine, we get the following results Nmap scan report for 10.129.96.74 Host is up (0.036s latency). Not shown: 65532 filtered ports PORT STATE SERVICE VERSION 80/tcp open http Microsoft IIS httpd 10.0 | http-methods: |_ Potentially risky methods: TRACE |_http-server-header: Microsoft-IIS/10.0 |_http-title: Mega Engines 5985/tcp open http Microsoft HTTPAPI httpd 2.0 (SSDP/UPnP) |_http-server-header: Microsoft-HTTPAPI/2.0 |_http-title: Not Found 8080/tcp open http Jetty 9.4.43.v20210629 | http-robots.txt: 1 disallowed entry |_/ |_http-server-header: Jetty(9.4.43.v20210629) |_http-title: Site doesn't have a title (text/html;charset=utf-8). Service Info: OS: Windows; CPE: cpe:/o:microsoft:windows Service detection performed. Please report any incorrect results at https://nmap.org/submit/ . Nmap done: 1 IP address (1 host up) scanned in 109.79 seconds When looking at port 8080, we find a Jenkins with an open registration form. When registering there, we can create a new project via New Item -> Freestyle Project. ...

Steam Technologies is a service provider which uses strictly steam-powered computers. They have recently developed a new type of oracle taking advantage of the steam-power architecture. They offer a huge price in case someone decrypts the message from their service. Are you up for the challenge? Category: crypto Solver: n1k0, nh1729 Flag: HTB{m4ng3r5_4tt4ck_15_c001_4nd_und3rv4lu3d} Writeup We need to decrypt an RSA ciphertext and for that we are provided with the ciphertext, the public key, and an oracle. We can query the oracle with ciphertexts, it decrypts them with the private key belonging to the provided public key, and then responds with the byte length of the decrypted message. ...

Quick we need to get access to the bunker and we are running out of time! The door is using an advanced steam-powered door locking mechanism which we cannot breach. One of our scientists managed to make a tool that measures the mechanical stress of the pipes moving steam during the verification of the password and created a power consumption model but it looks like just random signals. Can you find anything useful in the data? ...

An unknown maintainer managed to push an update to one of our public docker images. Our SOC team reported suspicious traffic coming from some of our steam factories ever since. The update got retracted making us unable to investigate further. We are concerned that this might refer to a supply-chain attack. Could you investigate? Docker Image: steammaintainer/gearrepairimage Category: forensics Solver: 3mb0 Flag: HTB{1_r34lly_l1k3_st34mpunk_r0b0ts!!!} Writeup Firstly, we download the provided docker image with docker pull steammaintainer/gearrepairimage and inspect the layers of it on DockerHub [1]: ...

On a path to avenging his father, Tex Chance manufactured steam-powered robots to capture all the animals of your island to build a powerful army of fused mutated organisms using his powerful Sigma technology. You can’t let them take away your loyal doggo Julius. The robots have been trained to classify all the objects they encounter using the SigmaNet network. Can you use your laser pointer to change some of the robot’s vision pixels forcing it to misclassify your dog’s image as a non-animal object? ...

You’ve found a portal for a firmware upgrade service, responsible for the deployment and maintenance of rogue androids hunting humans outside the tractor city. The question is… what are you going to do about it? Category: Web Solver: rgw, nh1729, n1k0 Flag: HTB{i_slipped_my_way_to_rce} Writeup In this web challenge, we get a docker template of a flask web server. The user can upload .tar.gz archives which are extracted into a temporary directory on the server. Then, the structure is moved to a static directory to be presented to the user. The flag can be found in a file on the system. ...

Jones and his crew have started a long journey to discover the legendary treasure left by the guardians of time in the early beginnings of the universe. Mr Jones, though, is wanted by the government for his crimes as a pirate. Our agents entered his base and discovered digital evidence about the way captain Jones contacts with his closest friends back home. We managed to get his last message, sent to his best friend. Could you help us decrypt it? ...

We’ve installed our Kubernetes cluster inside a steam powered computer, however there’s a lot of smoke, therefore we think a bolt is missing. Could you please investigate? Category: cloud Solver: t0b1 Flag: HTB{dOn7_3Xpo53_Ku83L37} Writeup According to the challenge description, we will face a Kubernetes cluster which we will have to exploit. Using nmap, we find the following open ports, most of which appear to be known Kubernetes ports: 22/tcp - ssh 2379/tcp - etcd 2380/tcp - etcd 8443/tcp - Kubernetes API (normally on port 6433) 10249/tcp - Kubelet API 10250/tcp - Kubelet API 10256/tcp - Kube-Proxy health check First, we do some basic checks against the Kubernetes API port. A curl -k https://10.129.228.17/livezreturns ok. That shows the Kubernetes is alive and running. Next, we check whether the anonymous user has too much access rights by running curl -k -X GET -H 'Accept: application/json' https://10.129.228.17:8443/api/v1/namespaces/default/pods/. However, that is not the case, as we receive a message that the anonymous user is not allowed to list the pods. ...

Meet SteamCoin, the first decentralized cryptocurrency of the SteamPunk realm that provides you the liberty to exchange value without intermediaries and translates to greater control of funds and lower fees. Sign up today in our SteamCoin wallet to get equipped with the tools and information you need to buy, sell, trade, invest, and spend SteamCoins. Category: Web Solver: nh1729, n1k0, t0b1 Flag: HTB{w3_d0_4_l1ttl3_c0uch_d0wnl04d1ng} Writeup The challenge consists of a Node.js web service hosted in a docker container. We are provided with the docker file. It is a login interface that allows creating new users and uploading files with common image file extensions. The users are managed by a CouchDB and the service is placed behind a HAProxy. ...

After following a series of tips, you have arrived at your destination; a giant vault door. Water drips and steam hisses from the locking mechanism, as you examine the small display - “PLEASE SUPPLY PASSWORD”. Below, a typewriter for you to input. You must study the mechanism hard - you might only have one shot… Category: Reversing Solver: s3rpentL0ver Flag: HTB{vt4bl3s_4r3_c00l_huh} Writeup The challenge is downloaded via a zip file. After unpacking it, we get a single executable file named “vault”. The first thing we do when we download a potentially malicious executable is, of course, to execute it. The output looks like this: ...

As you approach SafetyCorp’s headquarters, you come across an enormous cogwork tree, and as you watch, a mechanical snake slithers out of a valve, inspecting you carefully. Can you build a disguise, and slip past it? Category: misc Solver: 3mb0, lmarschk Flag: HTB{45ts_4r3_pr3tty_c00l!} Writeup For this challenge, we can download the python code (python 3.10 to be able to use the new match-case statement) for a server that offers python remote code execution via eval. But the server has some security checks to prevent us from executing arbitrary python code: ...

We received this strange advertisement via pneumatic tube, and it claims to be able to do amazing things! But we there’s suspect something strange in it, can you uncover the truth? Category: reversing Solver: rgw, 3mbo Flag: HTB{33zy_VBA_M4CR0_3nC0d1NG} Writeup For this challenge, we can download a zip file. When unpacking it, we see a single file Upgrades.pptm. When opening the presentation in LibreOffice, we immediately find that it contains macros: ...

Your mechanical arm needs to be replaced. Unfortunately, Steamshake Inc which is the top mechanical arm transplants has a long waiting list. You have found a SQL injection vulnerability and recovered two tables from their database. Could you take advantage of the information in there to speed things up? Don’t forget, you have a date on Monday! Category: crypto Solver: n1k0 Flag: HTB{t3ll_m3_y0ur_s3cr37_w17h0u7_t3ll1n9_m3_y0ur_s3cr37_15bf7w} Writeup In the provided source code we see that we need to provide a signed message (ECDSA) for a specific appointment to get the flag. Additionally, there is a list of appointments and a list of signatures for these appointments. So probably we need to use this to forge a signature. It is suspicious that we also get the 7 least significant bits of the nonce k, which is used for signing. A quick research on malleability and private key recovery of ECDSA signatures [1][2] reveals that not only the reuse of k or a bias in its selection poses a security issue, but also leakage of the nonce, even partially, can be used to recover the private key if enough signatures are provided. ...

The devil is enticing us to commit some sandboxed SSTI feng shui, would you be interested in doing so? Category: web Solver: davex, shm0sby Flag: HTB{b3nt_tw1g_t0_my_will!} Writeup The task was very simple. We had the source code of the challenge and we knew there was /flag which might contain our flag. ;) The challenge used Symfony as application framework and Twig as templating engine. We simply had to use basic injection on Twig which could be found in [1]. ...

I wrote this advanced program to only work on my computer but I think I might have made a mistake somewhere, as I can’t even confirm my own identity. Category: reversing Solver: t0b1 Flag: HTB{Id3nt1ty_c0nf1rmat1on} Writeup In this challenge we get a Windows executable. We open it up in Ghidra to see what it does. The main function is printing Starting to confirm identity... and then calls the RegOpenKeyExA function with Control Panel\Desktop as the argument. ...

After a long investigation we have revealed the enemy’s service, which provides their agents with any needed documents. Recent events indicate that there are double agents among us. We need to read the double_agents.txt file in order to identify their names and treat them accordingly. Can you do it? Category: crypto Solver: kh1 Flag: HTB{1v_sh01d_b3_r4nd0m} Writeup When connecting to the server, it sends Welcome, agent! Request a document: When sending something after this, the server interprets it as hexadecimal data and decodes it. If the decoded data is a multiple of 16 bytes long, it is decrypted (using AES in CBC mode) and the content of the file with the decrypted string as name is returned. ...

Hackers made it onto one of our production servers. We’ve isolated it from the internet until we can clean the machine up. The IR team reported four different backdoors on the server, but didn’t mention what they were and we currently can’t get in touch with them. We need to get this server back into prod ASAP - we’re losing money every second it’s down. Please find the four backdoors (both remote access and privilege escalation) and remove them. Your creds are user / hackthebox, and that user will have full sudo rights, so running sudo su - will provide a shell as root. Remove any malicious files and configurations, and then run /root/solveme as root to get the flag. ...

Our domain has been attacked. An APT group has taken over our server and they have locked us out. Our incident response team was able to find some files added on the upload directory but havent been able to extract any information from them. Could you help us login back? Category: crypto Solver: Miroka, HTTP418, kh1 Flag: HTB{15b_4tt4ck5_4r3_c001} Writeup What we got encryption.py - the script used to encrypt the new password leaks - the script’s variables n, rp, and rq new_password - the encrypted new password encryption.py resembles RSA encryption with two primes p and q that are slightly above square numbers and the variables rp = 228 and rq = 75 tell us, how much above. We have also given the implicit RSA-e-Variable of the public key as it is a constant in the encryption.py. ...

Time for an emoji-test! No need to worry.. You have 500 seconds to answer 100 questions. Five seconds for each question is more than enough! You need to score 100/100 in order to win an amazing prize! Good luck! Category: misc Solver: lmarschk Flag: HTB{3m0j1s_R_fUn_4nd_m4k3_m3_c0d3_f4st} Writeup Starting with a telnet connection to the server, we are given a set of questions: Trying 139.59.202.58... Connected to docker.hackthebox.eu. Escape character is '^]'. You have only a few seconds for each question! Be fast! ⏰ Question 1: ❌ 🌞 🍧 👺 🦄 - 🦄 ❌ 🦄 👺 Answer: > 123 Time: 2.47 Wrong answer! 😿 The correct answer was 11382 The problem is, that when it is taking too long to get an answer, the connection will be shut down from the server. So there is no possibility to solve this one “by hand”, needing a script in order to do so. ...

There is serious suspicion that John is a double agent. We found the cipher in his trash can. It looks like he extracted the message and forgot to get rid of the evidence. Can you decrypt the secret message? Category: crypto Solver: kh1 Flag: HTB{m1551ng_v4lu35_m4k3_m3_s1ck} Writeup flag.txt contains a list of 32 lists containing 32 numbers from 0 to 255 each. This is a One-Time-Pad with 32 parts, xoring the lists and interpreting the result as ascii code gives the flag. ...

Just some not so regular disable_functions / open_basedir PHPfu. Category: web Solver: davex, shm0sby, lmarschk Flag: HTB{iconv_r34lly_b3_d01ng_us_lik3_th4t} Writeup The challenge php file was quite simple itself, it was a Docker container with some further configs. The configs were the more interesting thing. The php file only included an GET-parameter which then has been sent to an eval()-call. Also we know there is a file called /readflag which obviously prints the flag. ...

A brave warrior stands in front of the harshest enemy, a untouchable evil spirit who possesses his allies. Will they be able to overcome this enemy? Category: reversing Solver: 3mb0, HTTP418, mp455 Flag: HTB{Retr0_Kunai} Writeup We found ourself here in a reversing challenge. So - as we were used to - we prepare for a static binary analysis. Open Ghidra and install the GhidraBoy [1] to inspect the Game Boy ROM. ...

You’re being interrogated in the enemy’s headquarters. Fake it and get out of there alive, without telling them anything! Category: pwn Solver: t0b1, Pandoron Flag: HTB{m0ms_sp4gh3tt1_1s_f4k3!} Writeup The first thing we do is running the checksec tool to get any clues where this challenge might be heading. It outputs the following. [*] '/home/user/htb-unictf-2020/finals/pwn/reality_check/reality_check' Arch: i386-32-little RELRO: Full RELRO Stack: No canary found NX: NX enabled PIE: No PIE (0x8048000) We extract the following information: ...

A remote facility is secured by a two-part access control system. The exterior device contains a keypad that is connected to a microcontroller, which sends entered passwords to a remote API for authorization. During an operation, we succeeded in tapping the connection between the keypad and embedded device. The only thing preventing us from gaining access to the facility now is to decode the obtained data and send the password to /api. ...

During your usual crop field stroll you were abducted by aliens. Luckily you were able to escape their grip and flee to an escape pod, but alas starting it requires a key code. Figure out how this strange mechanism works and return to earth. Category: reversing Solver: t0b1 Flag: HTB{_3st3r31K3yP4d_} Writeup In this challenge we get a binary. We start by analyzing it in Ghidra and find the following main function (we already renamed the functions to be more readable). ...