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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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How do I host a binary as a service over TCP using Docker?

I have learned how to use Docker containers, and I'd like to set up a container which contains a binary so that: If I ssh to the Docker container, I am prompted as though I had just executed the binary locally If I hit a condition that causes the…
growling_egg
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How to manually figure out which linker to use with a given libc file and given binary?

Background is I am looking at an old CTF challenge from pico-CTF. You do have the Makefile, the binary itself and the correspondig libc file available. However the binary will not run on my machine but abort with a segmentation fault. According to a…
Zapho Oxx
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how to solve rsa related message attack with exponent of 65537?

c1 = ([message] + b'good')^e mod N c2 = ([message] + b'hello')^e mod N we got c1,c2 and e, N.how to get message recover e.g: from Crypto.Util.number import * N = getPrime(1024) * getPrime(1024) e = 65537 m =…
chris yang
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I extracted a file using binwalk. I discovered it has a TROC file, how do I read or extract the contents of the TROC file?

DECIMAL HEXADECIMAL DESCRIPTION 33211 0x81BB TROC filesystem, 1263425345 file entries 948694 0xE79D6 StuffIt Deluxe Segment (data): f:IK
Varnit Jain
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Cannot upgrade simple shell to fully interactive session

I am learning CTF and have problems with upgrading shell. This is instruction I use - https://blog.ropnop.com/upgrading-simple-shells-to-fully-interactive-ttys/#method-3-upgrading-from-netcat-with-magic Method 1 does not help - Ctrl+C stopes…
Alexal
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unix pipeline causing program to terminate early

So I was attempting a CTF recently, and I needed to input some non-printing chars into stdin in order to overwrite a stack variable. I decided to pipe the output from a printf command into the program, and this worked to overwrite the variable, but…
mPrime
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one python question during the capture the flag game

Among all the CTF puzzles, i am clueless of this one. Below is the function part of code. You use the input function to type in the string and verify_password will validate the string to see if it is the correct password. I try to follow the…
user3768947
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XSS Attack without Web Hosting

I am learning about XSS attacks. Suppose I have a website (let's call it http://www.animallover.com) which allows me to enter anything into a search bar to search for animal names. The website is vulnerable, as entering …
SugarDrink
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CTF running a script by opening and reading it

I have the following file -rwxr-sr-x 1 root reader 15555 janv. 1 00:00 reader -rw-r----- 1 root reader 65 janv. 1 00:00 flag.txt drwxr-x--x 2 root reader 4096 janv. 1 00:00 dir Inside dir, I have the file -rw-r--r-- 1 root reader janv. 1 00:00…
JavaDumbell
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PHP when md5 returns null value

I have a question. So I was doing ctf and there was this if statement. I have no idea how to get past it. if(isset($_POST['var']) && md5($_POST['var']) == NULL) All I'm asking for is a little hint, thanks.
Patrikkk
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Is is possible to start python code in cobra compiler

So I have this code in python, but it wont run as numbers are too large for python to handle, I've found out that there is such thing as Cobra which works faster, almost as C++ and can handle a task like this. I've tried rewriting the code myself,…
Mark
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Need help on format string vulnerability

#include #include #include int main(int argc, char **argv){ int i = 1; char buffer[64]; snprintf(buffer, sizeof buffer, argv[1]); buffer[sizeof (buffer) - 1] = 0; printf("Change i's value from 1…
Bestofallnicks
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Why use cat to open interactive shell?

(Asking again without the download link) Problem Description Nana told me that buffer overflow is one of the most common software vulnerability. Is that true? bof.c #include #include #include void func(int key){ …
luke.lcim
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Issue with installing Facebook CTF

I am trying to install Facebook CTF from https://github.com/facebook/fbctf Following the instructions, I execute ./extra/provision.sh -m prod -s $PWD All goes well, until it gets to the section where it runs grunt. It's hitting this code in a…
user3424029
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What is the difference between ''find .'' and ''find /'' on linux command

I am solving overthewire bandit. I looked solutions but there is no explanation about it. For example when i use find . find it on bandit 5->6 bandit5@bandit:~/inhere$ find . -type f -readable ! -executable -size…
Emin Kotan
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