ehamberg

#include <mpi.h>
#include <stdio.h>
#include <stdlib.h>
#include <math.h>

#define SIZE 4

int main(int argc, char *argv[])
{
    int rank, size; // for storing this process' rank, and the number of processes

letoh

原文 Assembler / なぜx86ではMBRが"0x7C00"にロードされるのか？(完全版)

感謝 descent 大大分享本文，隨便看隨便譯。本文不是逐句譯，同時也不是這方面的專家 (不管是語言或技術)，用語不一或缺漏錯誤在所難免，歡迎自行 fork 修正指教

誰適合看本文?

對 x86 架構與組合語言有基礎認識，以及從 MBR 到載入 OS 這一段過程有興趣的人 (還有談到中斷向量或 INT xxx 時不會一臉茫然的人)

aspyct

/**
 * More info?
 * a.dotreppe@aspyct.org
 * http://aspyct.org
 *
 * Hope it helps :)
 */

#include <stdio.h>
#include <stdlib.h> 

jeremy5189

#!/usr/bin/python
# -*- coding: utf8 -*-

# Simple RSA Implementation
# Authored by Jeremy <jeremy5189(at)gmail.com>
# Reference: http://www.ruanyifeng.com/blog/2013/07/rsa_algorithm_part_two.html

from fractions import gcd
import sys

nikAizuddin

;          1         2         3         4         5         6         7
;01234567890123456789012345678901234567890123456789012345678901234567890
;=======================================================================
;+---------------------------------------------------------------------+
;|                                                                     |
;| Example using brk() system call for dynamic memory allocations.     |
;|                                                                     |
;| DON'T CONFUSE that brk() used in C Function is different with brk() |
;| systemcall (systemcall 45 for x86 ASM).                             |
;|                                                                     |

Neo23x0

This Gist has been transfered into a Github Repo. You'll find the most recent version here.

YARA Performance Guidelines

When creating your rules for YARA keep in mind the following guidelines in order to get the best performance from them. This guide is based on ideas and recommendations by Victor M. Alvarez and WXS.

• Revision 1.4, October 2020, applies to all YARA versions higher than 3.7

lpsantil

; src/boot/boot.asm
; Bootloader to load kernel, switch to 32-bit protected mode and execute kernel

[BITS 16]                               ; 16-bit real mode
[ORG 0x7C00]                            ; Loaded into memory at 0x7C00

MOV [bootDrive], DL                     ; Store DL (boot drive number) in memory

MOV BP, 0x9000                          ; Move Base Pointer in free memory space
MOV SP, BP                              ; Move Stack Pointer to base of stack

scottt

== malloc()
	_dl_init_paths()

Catchpoint 1 (syscalls 'mmap' [9] 'mprotect' [10] 'munmap' [11])
Breakpoint 2 at 0x1650: file src/true.c, line 59.

Catchpoint 1 (call to syscall mmap), 0x00007ffff7df54da in mmap64 () at ../sysdeps/unix/syscall-template.S:84
84	T_PSEUDO (SYSCALL_SYMBOL, SYSCALL_NAME, SYSCALL_NARGS)

Catchpoint 1 (returned from syscall mmap), 0x00007ffff7df54da in mmap64 () at ../sysdeps/unix/syscall-template.S:84

graugans

How I solved Nebula Level 11

The last few days I solved the first levels of Nebula. Nebula is an exploit exercise which consists of twenty levels. The level zero to eight where no real trouble. The level09 drove me crazy. I never wrote serious php code so I was not able to solve the string injection without cheating. For [level10] I gave up a bit too early as-well, after the first hint about TOCTOU (time-of-use to time-of-check) made me solve this with two simple bash scripts.

For the Level 11 flag cheating was no option for me. This walk through describes how I did solve this exercise. The description of this exercise states the following:

The /home/flag11/flag11 binary processes standard input and executes a shell command.  There are two ways of completing this level, you may wish to do both :-) To do this level, log in as the level11 account with th

rain-1

WannaCry|WannaDecrypt0r NSA-Cyberweapon-Powered Ransomware Worm

• Virus Name: WannaCrypt, WannaCry, WanaCrypt0r, WCrypt, WCRY
• Vector: All Windows versions before Windows 10 are vulnerable if not patched for MS-17-010. It uses EternalBlue MS17-010 to propagate.
• Ransom: between $300 to $600. There is code to 'rm' (delete) files in the virus. Seems to reset if the virus crashes.
• Backdooring: The worm loops through every RDP session on a system to run the ransomware as that user. It also installs the DOUBLEPULSAR backdoor. It corrupts shadow volumes to make recovery harder. (source: malwarebytes)
• Kill switch: If the website www.iuqerfsodp9ifjaposdfjhgosurijfaewrwergwea.com is up the virus exits instead of infecting the host. (source: malwarebytes). This domain has been sinkholed, stopping the spread of the worm. Will not work if proxied (source).

update: A minor variant of the viru