ZoZo's Blog

How to start being an Hacker

2014-03-03T00:00:00+00:00

Today I met a bunch of very talented 9th grade students.

I thought it might be useful, if I list what it is recommended for start being an Hacker.

disclaimer: one should use the following tools and skills with responsibility and for good purposes, AKA White Hat Hackering.

Studying a low level languages:
- Assembly -ARM or x86 assembly. you might want to google for: NASM, ida and disassembly tools.
- C - IMO it is must to know how to code and understand the c code basics.
Studying networks basics.
Be familiar with web applications mechanism:
- Client side: HTML, Java Script.
- Server side (backend) e.g dotnet, ruby on rails, php, JavaServer Pages [JSP].
- Databases: SQL, nosql, Microsoft SQL, MySQL ,SQL injections.
Operating system internals.
Scripting: Linux shell, Microsoft power shell. running and writing batch files in windows, python.
practice within those tools:

I believe the list above is a great kick starting for a newbie, and the rest can be studied by “being into” security and studying things by yourself.

Generating list's subsets - Python

2013-12-03T00:00:00+00:00

Once a month a “how to generate all subsets in python” question appers on stackoverflow.

The OP (“Original poster”) of the question apparently found an itertools based implementation.

But what he really looked for is an algorithm to create all the subsets.

There are fewer solutions on stackoverflow that implements the naive alogrithm in python.

Unfortuntally I couldn’t find the awesome and elegant original post, but I rewrote it somehow and post it here.

The naive implementation:

def naiveSubsetGen(s):
	subsets = [[]]
	for i in s:
		subsets = subsets + [[i] + j for j in subsets]
	return subsets

The itertools solution:

from itertools import combinations

def itertoolsSubsetGen(s):
	return [[]] + [list(j) for i in range(len(s)) for j in combinations(s, i+1)]

I benchmarked both of them:

itertoolTestStr=\
"""
for i in xrange(5,25,5):
	itertoolsSubsetGen(range(i+1))
"""

naiveTestStr=\
"""
for i in xrange(5,25,5):
	naiveSubsetGen(range(i+1))
"""

setupItertool = """from __main__ import itertoolsSubsetGen"""
setupNaive = "from __main__ import naiveSubsetGen"
if __name__=='__main__':
	import timeit
	print "naive time:", timeit.timeit(naiveTestStr, setup=setupNaive, number=4)
	print "itertools time:",timeit.timeit(itertoolTestStr, setup=setupItertool, number=4)

Results:

naive time: 8.25990605354
itertools time: 12.5649080276

Mono for MAC - C# for mac OSx

2013-11-30T00:00:00+00:00

Was trying for the first time running mono on mac osx. Tracing the steps I went through.

Download and run Mono MRE installer from http://www.go-mono.com.

create a hello.cs file and feed it with the helloworld code:

using System;
using System.Windows.Forms;
 
public class HelloWorld : Form
{

	static public void Main ()
	{
		Application.Run (new HelloWorld ());
	}

	private void buttonClickFunc(object sender, EventArgs ei)
	{
		MessageBox.Show("How cool is that ?");
	}

	public HelloWorld ()
	{	
		Text = "Hello Mono World";
		Button button = new Button();   
		button.Left = (this.Width - button.Width) / 2;
		button.Top = (this.Height - button.Height) / 2;
		this.Controls.Add(button);      
		button.Text = "Hello";
		button.Click += buttonClickFunc;
	}

}

Now let’s compile and execute the snippet:

gmcs hello.cs -pkg:dotnet

Mostly you will encounter the following error:

Package dotnet was not found in the pkg-config search path.
Perhaps you should add the directory containing `dotnet.pc'
to the PKG_CONFIG_PATH environment variable
No package 'dotnet' found
error CS8027: Error running pkg-config. Check the above output.

we need to add PKG_CONFIG_PATH the path of the dotnet package. In order to figure out where the package is located.

sudo find / -iname "dotnet.pc"

Copy the directory found e.g.

/Library/Frameworks/Mono.framework/Versions/3.2.5/lib/pkgconfig/

to PKG_CONFIG_PATH:

edit .bash_profile or .bashrc files

sudo vim ~/.bash_profile

and add the next line at the end of the file

export PKG_CONFIG_PATH="$PKG_CONFIG_PATH:/Library/Frameworks/Mono.framework/Versions/3.2.5/lib/pkgconfig/"

open a new bash or

source ~/.bash_profile

. and then we right to go compiling the code and execute it:

gmcs hello.cs -pkg:dotnet
mono hello.exe

Hello World

2013-10-11T00:00:00+00:00