About the challenge : The challenge was pretty simple. It was more of a reversing challenge than a pwning challenge. Since it was a binary challenge, I started looking for bugs (I am a newbie in pwning ) and finally there is an fgets() function. But to reach the function we have a few constraints….
Playing with z3
It has not been very long since I got introduced to z3. But earlier I didn’t use it much. Now since I got to know the practicality of z3, I started using it. So out of my excitement and love for it, I started solving reverse challenges using z3. This post is not gonna be…
Forgetful_Commander (Hack.lu-2k18)
So here I am again with a new post, write up of a challenge from HackLu-2k18. This CTF, I could only solve one challenge during the CTF. And the fun part was that, I was present there during the CTF as I was attending the HackLu-2018 conference at Luxembourg.I will be writing about that in…
WhiteHat 2k18 – re06
WhiteHat came just after the Hackon CTF. I did not try the challenge during the CTF. But then the challenge was quite decent.It was a .net binary. About the binary: The binary was .net so I decided to use ILSpy to disassemble it. It was written in C#. The disassembled code was very clear and…
Hackon-2k18 BE
Most of the binary challenges from the CTF were easy, based of basic BOF and basic ROP. She sells sea shells – 90 points Analyzing the binary we find a gets function which is vulnerable. Going through checksec everything other than RELRO (partial) is disabled. Also the ASLR is turned on. No worries the program…
Hackon-2k18 Revfcuk
The challenge was pretty easy. It had some conditions to bypass to get to the actual flag checking. About the binary: I first opened the binary in IDA and saw that there were 5 conditions to bypass and then only we can go to the flag checking process. Patching and bypassing: Opening the binary gdb…
Basic Syscalls in x86
What is a Syscall? System calls are requests that a program can pass to an operating system, to make it act on the program’s behalf in carrying out some task the program itself can’t do. Basic Syscalls: read write open close fork execve Each syscall has its own specific arguments. About read syscall: We use…
ASIS-QUALS’18 DENSITY CHALLENGE
The program took the string as an input and then added 2 random strings and added them before and after it. Inside the function: It takes each letter from the string and check whether it is present in “@$_!\”#%&'()*+,-./:;?\n” and returns the position of the character. If it is not null then it replaces that…
Debugging using GDB
So here I am, up with my first blog post. This post is basically an intro on how to debug a program using gdb. GDB or GNU Debugger is extensively used in debugging programs written using mainly Ada, C, C++, Objective-C, Free Pascal, Fortran, Go, Java. In this post I am going to explain how…
b3y0nd3r 