Robbert

There are 5 three pwn challenges, but I only sloved 2 challenges. These are write-ups for them: Poetry of a bugAttachment Rerversing create_pdf and add_metadata helps me recover Entry and Pdf struct: 12345678910111213141516171819202122232425262728293031323334353637383940414243444546struct Entry{ char name[50]; char value[100];};struct __attribute__((packed)) __attribute__((aligned(4))) Pdf{ Stream *next; int stream_count; Entry entries[10]; int entries_num;};Pdf *create ...

Better than last year! Todo ListAttachment This is a normal heap-note challenge. There is a logic bug in this program that can lead to a buffer-overflow attack. The create function doesn’t check if there are || strings in desc or title: 1234567891011121314void __fastcall create(){ ... printf("Title: "); v1 = read(0, buf->title, 0xFuLL); if ( buf->title[v1 - 1] == 10 ) buf->title[v1 - 1] = 0; ... printf("Desc : "); v1 = read(0, buf->des, 0x18uLL) ...

This time, I’ve played with my new team Alternative für Knights.Our team was on the top 6. EinsteinAttachment 123456789101112131415161718192021222324252627282930313233int __cdecl handle(){ int offset; // [rsp+8h] [rbp-38h] BYREF unsigned int size; // [rsp+Ch] [rbp-34h] BYREF unsigned __int64 *wher; // [rsp+10h] [rbp-30h] BYREF unsigned __int64 wat; // [rsp+18h] [rbp-28h] BYREF unsigned __int64 *wher2; // [rsp+20h] [rbp-20h] BYREF unsigned __int64 wat2; // [rsp+28h] [rbp-18h] BYREF c ...

Hello and Happy new year!! Today I will write about building til for IDA. The Physical Test challenge is used for exampling. Why this time? Because I’m too lazy. But now I’ve not only written the solution for the challenge but also introduced a new way to reverse the Linux module file, which helps you reduce the time it takes to reverse; use that time to pwn. You can get challenge’s files here. What is TIL“TIL” stands for “Type Library” . It includes defenitions of many structors, functions tha ...

This is write-up for challenges which I solved during the event. You can find attachments (included unsolved challenges) here. Quals roundUnfortunally, I couldn’t solve any pwnable challenges because they are too hard but luckily there is a challenge in Audit catagory that I could solve it. no-name minorA float variable stop incrementing at 16777216 First, I load $16777216$ and buy a name. I loan one by one, and my cash increases, but the debt doesn’t change. After buying the name, we can call ...

Last week, we - m1cr0$oft 0ff1c3 team participated in this event and got 21th place. These pwn challenges are so damm hard, I did only solve 2 challenges. This is the write-up for babybs challenge with the intentded way ( I used this way during the CTF event ). Attachment: babybs.tar.gz Check the files: At the first time, I had thought the OS booting had to take a long time so I had been waiting for it. But then when read the description , I decied to analyze the babybs.bin file with IDA. This i ...

Last week, we - m1cr0$oft 0ff1c3 team participated in this event and got 11th place. I’ve solved all Pwn challenges. But now I only show the solution for the “Swix” challenge. ( I feel this is only the “real” pwn challegne ). Attachemnt: Swix.zip We are provided the source code of this binray: 1234567891011121314151617181920212223242526272829303132333435363738394041424344454647484950515253545556575859606162636465666768697071727374757677787980818283848586878889909192939495969798991001011021031 ...

This year, I’ve played for m1cr0$oft 0ff1c3 team. We were in 24th place. zerodayAttachment Not like a normal Linux kernel exploit challenge. This challenge doesn’t provide any vulnerable driver. Then, I did check run.sh again carefully. 1234567891011#!/bin/shqemu-system-x86_64 \ -m 128M \ -nographic \ -kernel "./bzImage" \ -append "console=ttyS0 loglevel=3 oops=panic panic=-1 pti=on" \ -no-reboot \ -cpu qemu64,+smep,+smap \ -smp 2 \ -initrd "./i ...

Write up BFSMatrix Offsensive Con 2023The original tweet Attachment 12345678910111213141516171819202122232425262728293031323334353637383940414243444546474849505152535455565758596061626364656667686970717273747576777879808182838485struct matrix{ int rows; // number of rows in the matrix int cols; // number of columns in the matrix uint8_t* data; // 1-d backing data (rows x cols size) char name[MAX_MATRIX_NAME]; // name of the matrix struct matri ...

Zer0pts CTF 2023 writeupaush Attachment 1234567891011121314151617181920212223242526272829303132333435363738394041424344454647484950515253545556575859606162636465#include <fcntl.h>#include <stdlib.h>#include <string.h>#include <unistd.h>#define LEN_USER 0x10#define LEN_PASS 0x20int setup(char *passbuf, size_t passlen, char *userbuf, size_t userlen) { int ret, fd; // TODO: change it to password/username file if ((fd = open("/dev/urandom", O_RDONLY)) == -1) ...