dmiessler.com | study

The Trailing Slash

Daniel Miessler — Sun, 15 Jun 2008 19:34:00 -0800

A discussion of whether or not one should include trailing slashes after directory hyperlinks. Includes a conclusion and evidence to back it up.

Understanding Subnetting

Daniel Miessler — Mon, 02 Jun 2008 00:10:00 -0800

A subnetting reference focused on reminding one how to find the answer vs. giving it to them.

Zone Transfers

Daniel Miessler — Mon, 21 Jan 2008 01:00:00 -0800

A short introduction to zone transfers, including how to perform them using host, dig, and nslookup.

Cross Site Scripting (XSS) Explained [Short Version]

Daniel Miessler — Mon, 24 Dec 2007 01:00:00 -0800

A list-formatted explanation of Cross Site Scripting (XSS).

Cross Site Scripting (XSS) Explained

Daniel Miessler — Mon, 24 Dec 2007 00:00:00 -0800

A simple explanation of Cross Site Scripting (XSS).

The Birthday Attack

Daniel Miessler — Thu, 27 Sep 2007 00:00:00 -0800

A simple explanation of the birthday paradox.

IMAP's IDLE Command

Daniel Miessler — Mon, 02 Jul 2007 00:00:00 -0800

What IMAP's IDLE command is (and isn't). Hint: it's not true "push" technology.

Hiding Your IP Address

Daniel Miessler — Mon, 01 Jan 2007 00:00:00 -0800

What to say to people who ask how to "hide" their IP address.

Network Ports

Daniel Miessler — Mon, 01 Jan 2007 00:00:00 -0800

Many who are new to networking and security wonder what it means to have “ports” open on your computer. Some get rather anxious when an online port scan reveals that something's open on their system. What follows is a silly, but hopefully memorable way for beginners to remember how nework ports work...

The Beauty of the Diffie-Hellman Protocol

Daniel Miessler — Mon, 01 Jan 2007 00:00:00 -0800

Diffie-Hellman is a key exchange protocol developed by Diffie and Hellman (imagine that) in 1976. The purpose of Diffie-Hellman is to allow two entities to exchange a secret over a public medium without having anything shared beforehand. As it turns out, this is an extremely important function, and understanding how Diffie-Hellman accomplishes this should be a point of interest for any information security enthusiast...

A Unix/Linux Permissions Refresher

Daniel Miessler — Sun, 01 Apr 2007 00:00:00 -0800

A refresher on Unix/Linux permissions, including uid, guid, and the sticky bit.

Harnessing The Über-Powerful Find Command (+xargs)

Daniel Miessler — Mon, 01 Jan 2007 00:00:00 -0800

find is one of the most useful Linux/Unix tools around, but most people use only a fraction of its power. Many Linux/Unix questions seen online can be solved using the find command alone; it's simply a matter of becoming familiar with its options...

Lsof: The Most Powerful UNIX/Linux Command Nobody Uses

Daniel Miessler — Tue, 01 Aug 2006 00:00:00 -0800

A primer on an extraordinarily powerful and underused UNIX/Linux command...

ICMP Basics

Daniel Miessler — Tue, 01 Aug 2006 00:00:00 -0800

The Internet Control Message Protocol (RFC 792) was designed to provide network connectivity information to administrators and applications. The protocol is broken up into two classifications: types, and codes. The types are the overall categories, and the codes are the individual messages within the categories...

Acceleration: Horsepower vs. Torque

Daniel Miessler — Tue, 01 Aug 2006 00:00:00 -0800

I purchased a new car recently and in doing so became (for the first time) moderately curious about its performance characteristics. I set about to see how it compared to my previous vehicle performance-wise and was immediately struck by a pivotal question: What matters more for acceleration -- horsepower or torque?

Security and Obscurity

Daniel Miessler — Mon, 01 Aug 2005 00:00:00 -0800

A short discussion of how security can actually benefit from obscurity if used correctly...

Not All SYN Packets Are Created Equal

Daniel Miessler — Fri, 01 Apr 2005 00:00:00 -0800

During a recent assessment I noticed that I was getting back (or, not getting back, as it were) a filtered response to nmap and hping SYN scans. That's normal enough for sites that drop incoming scan traffic, but the weird part was that if I used a standard connect scan, i.e. one that completes the three-way-handshake, I would get back a ton of open ports on the same host...

How To Remember Your TCP Flags

Daniel Miessler — Fri, 01 Apr 2005 00:00:00 -0800

Many people are familiar with the concept of a mnemonic [nəˈmɑnɪk] -- a memory device that uses a phrase based on the first letter of words in a series. Perhaps the most popular of these in the field of networking is the one for the OSI Model (All People Seem To Need Data Processing)...

A Tcpdump Primer