Questions tagged [ctf]
Capture the Flag (CTF) is a form of hacking competition. Use for questions about the design and operation of such contests. Do not use for questions asking for help with winning contests.
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Simple Buffer Overflow (Function Call) Problem
I'm trying to develop a simple buffer overflow CTF challenge inspired by the "Csaw 2016 Quals Warmup" challenge, here. I've managed to replicate the source code:
#include <stdio.h>
#...
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Hydra says different passwords with are correct each run, but only one works
I am doing CTF 'Skynet' from THM and came across this problem.
Enumerating SMB, I gathered credentials 'milesdyson' and a list of passwords 'log1.txt'.
I figured that I could try to brute force ...
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Encoding shellcode to hide in filename / directory
Working on a CTF challenge and the coordinators hint suggests that one of the vectors to inject shellcode is via pathing. Looking at debugging prints does show the cwd and filename are passed onto the ...
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Exporting shellcode to environment variable doesn't work as expected
(This is a question regarding a challenge in a wargame on overthewire.org called Narnia similar to Shellcode does not execute as the owner )
When exporting shellcode to EGG environment variable
export ...
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Trying to ret2text on 64bit program issues, can't jump to shell
Here is the elf summary of the program:
Arch: amd64-64-little
RELRO: Partial RELRO
Stack: No canary found
NX: NX enabled
PIE: No PIE (0x400000)
This is the ...
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What type of token is this?
I started noticing this kind of token in a lot of CTF tasks from different authors:
eyJlbWFpbCI6ImVtYWlsQG1haWxib3guZG9tYWluIiwiaWQiOjN9.ZLNCAQ.MxwKVKj_dramWyfT5XxT6g9U3xk
The structure is as follows:
...
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AES ECB cookie bypass
I am currently participating in a CTF Challenge and have reached a stage where I discovered a "log_admin" page. This page generates a cookie that is encrypted using AES 128 ECB. I obtained ...
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PHP CTF: Vulnerabilities in PHP before 2007?
I came across a CTF that i'm trying to solve, the goal is fairly simple: Bypass the authentication form and access the admin-restricted area. You can find the code snippet below.
Things to consider:
...
user291842
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Crashing the sha1() function in PHP?
I am working on the following war game from Defend The Web, which requires me to do a source code review to login as the user memtash. The code is on GitLab here.
Here is my methodology:
Reset the ...
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How long would this take to bruteforce?
I am working on the following war game from Defend The Web, which requires me to do a source code review to login as the user memtash. The code is on GitLab here.
Having inspected the source code ...
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Void pointer and their attribute constructor
I am supposed to find the vulnerability in the code (as a part of a ctf) and I feel it's hidden either in the __attribute__((constructor)) or the pointer.
Here I can make out that it's a void pointer ...
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64-bit ROP-based Buffer Overflow Attack
I am facing a CTF challenge in which I have to conduct an attack using a ROP chain on this program below:
#include <stdio.h>
#include <stdint.h>
#include <stdbool.h>
#include <sys/...
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Flask URL Vulnerabilities
I am doing a CTF-style assignment and I am confronted with a web site created in Flask. This web site appears fairly unremarkable - it has 4 pages and no log-in/authentication functionality, nor does ...
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Abusing Shell Feature for Privilege Escalation
This was covered in Linux PrivEsc, task 15, in this TryHackMe room.
I am having trouble understanding how this debugging mode is executing the commands in the PS4 variable, and why I must put /usr/...
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CTF Crypto question
The question in a CTF was this:
They used two hydrogen atoms (H2) from the SHA-256 molecule to encrypt
in some form of AES, and the result was as follows:
{mIT+GVt+p0YfgfOltHgqoetTS6h8bRSAScAGKrBE+...
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