The goal I wanted a small tool that tells you how weak or strong a password is, and explains why, not just gives a pass or fail. What you need Python 3, and about two hours if you’re new to it. How I built it The checker scores a password out of 5, based on…
Threat modeling is a structured way of thinking about the security of an application before something goes wrong. Instead of asking: “How could someone attack this website?” we start by asking: “What are we building, what needs protection, and what could go wrong?” Threat modeling helps developers and security teams identify risks early and decide…
Wireshark shows you every packet crossing your network interface. That sounds overwhelming until you know which three panes to look at and two or three filters to type. Part of How computers talk to each other Wireshark is a packet sniffer: it grabs the raw data moving across a network interface and shows it to you,…
Public-key cryptography can seem complicated at first, but the basic idea is simple: One key can be shared with everyone, while the other key must be kept secret. These are called a public key and a private key. The Mailbox Analogy Imagine a mailbox outside your house. Anyone can walk up to the mailbox and…
Cross-Site Scripting (XSS) is a web security vulnerability that happens when a website places untrusted user input into a webpage without properly handling it. In simple terms: The website expects data, but the browser ends up treating that data as code or markup. A Simple Example Imagine a website has a comment box: A normal…
SQL injection (SQLi) is a web security vulnerability that happens when an application incorrectly combines user input with an SQL query. SQL is the language applications use to communicate with databases. If an application treats untrusted input as part of the SQL command itself, a user may be able to change what the database query…
Linux uses file permissions to control who can read, modify, or execute files. This is an important part of Linux security because it prevents users and programs from accessing files they should not be able to use. The Three Basic Permissions Linux commonly uses three basic permissions: Permission Symbol Meaning Read r View the contents…
A firewall is a security system that controls network traffic according to a set of rules. Think of it like a security checkpoint. Instead of allowing every connection into or out of a system, the firewall examines traffic and decides whether it should be allowed or blocked. How Does a Firewall Work? When network traffic…
Whenever you visit a website, your browser communicates with a web server. Two common protocols used for this communication are HTTP and HTTPS. The important difference is that HTTPS adds encryption and authentication to the connection. What Is HTTP? HTTP stands for Hypertext Transfer Protocol. It defines how your browser and a web server communicate….
Phishing is a social engineering technique where an attacker tries to trick you into revealing information, clicking a malicious link, downloading a file, or performing an action that benefits the attacker. The attacker often creates a message that looks like it came from a trusted person or organization. How Does a Phishing Email Work? A…