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HackfestCTF 2024 Web writeup
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🚩 CTF
[ University ] We need to access to environment variable. @app.route('/', methods=['GET', 'POST']) def login(): if request.method == 'POST': username = request.form['username'] password = request.form['password'] try: response = requests.get(f"http://localhost:5000/api/users/{username}/auth") response.raise_for_status() conn = connect_db() cursor = conn.cursor() cursor.execute('SELECT * FROM use..
damCTF 2024 Web Writeup
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🚩 CTF
My team was too good for me to help, but here's a writeup I did on my own for studying purposes. Flower Power # app.py ... @dataclass class Flower: name: str flower_url: str description: str id: str = "-1" database: dict[str, Flower] = dict() def add_flower(flower: Flower): flower.id = generate_id() database[flower.id] = flower return flower add_flower(Flower( "Rose", "https://i0.wp.com/pikespea..
Phar Deserialization
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WEB
Serialization & DeserializationSerialization : 데이터 구조체나 Object 상태의 데이터를 다른 시스템 환경에서도 해석될 수 있도록 Byte Stream 상태로 변환하는 과정Deserialization : Byte Stream 상태의 데이터를 데이터 구조체나 Object로 변환하는 과정Phar (PHP Archive)Phar는 내부에 실행 가능한 PHP 코드를 모아놓은 아카이브 포맷을 뜻한다. Phar 파일은 아래 4가지의 구조로 이루어진다.StubManifestFile ContentsSiganutre (Optional)[ Stub ]Stub은 작은 형태의 코드를 담을 수 있는 공간이다. Stub의 마지막 명령어에는 반드시 _HALTCOMPILER()가 포함되어야 한..
CVE-2024-4367 (PDF.js - Arbitrary JS Execution)
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💻 Security
Vulnerable Product & VersionAll FireFox Users ( Services which use pdfjs-dist(SummaryPDF.js acts as a viewer to show a preview of a pdf file, which is made by Mozila.It has the ability to render fonts and CVE-2024-4367 vulnerabilitiy targets this part.The user can set the values of the PDF file's properties, and pdf.js applies them by executing JavaScript code.However, there is no validation of ..
[ Bug Report ] Success to exploit Skype (feat. RCE, pyzw file)
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Bug Report
• Executive SummaryI have recently discovered a critical Remote Code Execution (RCE) vulnerability in Skype. This bug presents a severe security risk as it enables an attacker to potentially take control of a victim's computer. Although this finding did not result in a reward or a CVE identification, it has been acknowledged as valid by Microsoft's security team, and I wish to document it for re..
BalsnCTF 2023 Web Writeup
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🚩 CTF
● Web3 (misc) You can find below code in "/" endpoint. const express = require("express"); const ethers = require("ethers"); const path = require("path"); const app = express(); app.use(express.urlencoded()); app.use(express.json()); app.get("/", function(_req, res) { res.send("Hello") }); function isValidData(data) { if (/^0x[0-9a-fA-F]+$/.test(data)) { return true; } return false; } app.post("..