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Questions tagged [ctf]

In a computer hacking context, a Capture The Flag (CTF) challenge invites participants to extract a hidden piece of information called a "flag" (usually a short string of ASCII text) from vulnerable online systems or downloadable files through the application of skills in various fields such as cryptography, steganography and reverse engineering. Typically this involves bypassing poorly-implemented security measures.

In a computer hacking context, a Capture The Flag (CTF) challenge invites participants to extract a hidden piece of information called a "flag" (usually a short string of ASCII text) from vulnerable online systems or downloadable files through the application of skills in various fields such as , and . Typically this involves bypassing poorly-implemented security measures.

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Is there a way to execute vim commands that are within txt file along with text?

I'm at my CTF final stage and there I have this: vim flag iCourse{v3ry_g00d_fl4g}[ESC]13hs1[ESC]am_[ESC]9l2xli_[ESC]2li3[ESC]vypaks[ESC]:s/ry/15 :wq I'm not really familiar with Vim so I can't figure out how to run this script. I'm guessing it…
Mak
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Stuck on bandit16 level at overthewire

I am trying to solve the CTF challenges at overthewire and have completed up to 16 levels To get from level 16 to 17 you have to send the password of the current level to the port supporting SSL on localhost after submitting the password an ssh…
Shailendra Sharma
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Jumping to an address inside a function

While trying to solve a challenge from a past ctf event I came across a unique problem that required me to do the followings: use the vulnerable method "gets()" to overflow the return address of the vuln function to another one and the stack cell…
revolution
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CTF Type Juggling with ripemd160 hash

I am trying to solve a CTF in which the juggling type should be used. The code is: if ($_GET["hash"] == hash("ripemd160", $_GET["hash"])) { echo $flag; } else { echo "

Bad Hash

"; } I made a script in python which checks random…
Agustin Ramirez
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Python: Why do my process returned by Popen has a "none" stdin?

I am trying to make a program in python to brute force a ctf C program where you have to find a fruit salad recipe in order to get the flag. what I want to do : I want to be able to write on the stdin of the C program in python. Problem : the stdin…
Fosowl
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Hack a unity game to load a secret level in the build

I am doing a ctf where I am supposed to hack a unity game and load a level which is in the build, but isn't supposed to be opened by default. I was thinking about using cheat engine since for some reason dnSpy doesn't do anything when I edit the…
Dejan Lisica
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How does the hex value in an URL change the path of the file?

I'm working on a challenge in CTF. Here's the link to the challenge: Link1 When I try to change the path to Link2. it successfully retrieved the flag but when the hex value is less than 80, it doesn't work. I'm a beginner and did a lot of digging…
tuz
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How to properly use z3 when calling a function that modifies the input

I am in the process of learning how to use z3 (I would like to use it during CTF challenges) and have hit a point where I am starting to agree with my wife's favorite saying "I need help" :) and I am posting here in the hopes that someone can review…
mmessuri
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sql_injection vulnerability in thinkphp5.0.x debug

I am recreating a sql injection vulnerability about thinkphp5.0.x I can already get the version() but I cannot get field content，it says： SQLSTATE[HY000]: General error: 1105 Only constant XPATH queries are supported` why？ thinkphp 5.0.15 php…
醉梦半醒
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Implementation of __toString() using eval() in PHP

I am looking for a way to implement the __toString method using only eval in PHP. The end goal is to be able to read a file. Note that this is part of a CTF challenge and not a real world application. I am given the following implementation function…
Marc Ilunga
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How could I get all strings from .elf file?

I have a file and VirusTotal (from one of "Shadow CTF" contests) that have a few strings in it. I used IDA to get all the strings, but I get only "error" string. I have already tried hex editing this file but that gave nothing. I am a beginner at…
DEMKS
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How to download a java applet class file in a page with an adress like 46.XXX.XX.XX:8008/

I am working on CTF challenge and there is a link with the challenge, that looks like that : 46.XXX.XX.XX:8008/ If I open the Developer Tools in that page, I can find an applet, with the attribute code with value of "mPage.class"
Hamza Ince
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Cryptography CTF Exercise - AES-CTR

I got these files for a homework. No clues, no help, just two files, source.py and secret.enc that should make me understand how I should identify that flag by means of the type of encryption used. This is the code of source.py: from Crypto.Cipher…
bobodrg
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Simplify large Flow graph of decompiled android apk's function

I was attempting one CTF on mobile dev, While decompiling the apk to find the flag, I found that Jadx as well as JD-Gui was not able to decompile one class's function completely. From AndroGuard Flow graph i realized that the class's function…
Sandeep Mishra
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RSA Oracle - Getting the flag by using chosen ciphertext attack

I am trying to solve a simple RSA CTF challenge, but I am facing problems that go beyond the theory behind the attack (or at least I guess so). Basically, I have an oracle at disposal that will first print the encrypted flag and then encrypt and…
Shark44
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