Penetration testing course: 0x02.2 Hexadecimal Numeral System

In the previous article we saw how binary numbers are represented and how to convert from decimal to binary and vice versa, finally how to perform operations like addition, substraction, multiplication, division and bitwise operations between binary numbers. In this lesson we’ll talk about the hexadecimal system and why it is important for computer science in general. DEFINITION In mathematics …

Juniper ScreenOS backdoor: the attack demystified

Juniper Networks is a multinational corporation headquartered in Sunnyvale, California that develops and markets networking products. Its products include routers, switches, network management software, network security products and software-defined networking technology. On 18th December 2015 a critical vulnerability (CVE-2015-7755) affecting ScreenOS 6.3.0r17 through 6.3.0r20 was disclosed. The impact is huge because many routers and switches are powered by Juniper ScreenOS. …

Penetration testing course: 0x02.1 Fundamentals of binary arithmetic

Any information processed by a computer is stored in binary format so it is fundamental that anyone is familiar with this numeral system. DECIMAL SYSTEM When we count we normally use the decimal system (base 10). Ten is the number which is the count of fingers and thumbs on both hands (or toes on the feet). Positional decimal systems include a …

Penetration testing course: 0x01 Introduction

I often receive messages from people asking me how to become a hacker, how to hack a website or how to become a professional penetration tester. I usually reply case by case if I’m free and if I feel the person is truly interested in the field and he’s not trying to do some illegal activities (often without the minimum …