« Back to home

Confidentiality and Integrity vs Availability

In computer security, there are three main axes for consideration - confidentiality, integrity, and availability (CIA).  These are commonly thought of as things you desire out of a secure system.  You want your communications to only be available to the intended agents, you want them to remain unchanged except when you intend them to change, and you want them to be available when you need them.  Preferably, you want your communications to have all of those properties.

Read more »

Building Your Own OpenVPN

I’ve wanted to have a VPN setup for a while - I’ve never been entirely comfortable when using public wifi, even secured public wifi…  Open wifi?  I feel a little crazy every time I connect.  But I usually console myself that I’m not a target, I can make sure important connections are encrypted, and I can just avoid doing some things while on public wifi.

A VPN though, that could make things much easier!  All communications would be encrypted between the device I’m using and my VPN endpoint.  If I set it up myself, the VPN endpoint would be my home Internet connection.  This essentially makes all my browsing look like it’s coming from home, with solid protection between the coffee shop and home…  I could do any browsing I wanted without worry!  Also, I would essentially be connected to my home network, giving me access to all my devices there.

Read more »

Open Port

Every now and then when I’m at a coffee shop I wonder what ports I’ve got open on my home network.  Normally I don’t have any ports open within Nmap’s default port list.

Starting Nmap 6.01
Initiating SYN Stealth Scan at 16:41
Scanning myRouter [1000 ports]
Discovered open port 1111/tcp on myRouter
Completed SYN Stealth Scan (1000 total ports)
Not shown: 999 filtered ports
PORT STATE SERVICE
1111/tcp open lmsocialserver




Read data files from: /usr/local/bin/../share/nmap
Nmap done: 1 IP address (1 host up) scanned in 184.69 seconds
 Raw packets sent: 1999 (87.956KB) | Rcvd: 3 (212B)

Crap.  What’s that?  Port 1111 should not be open.  It wasn’t last time I checked, less than a month ago I think.

Read more »

Advanced SQL Injection

Ok, here’s a great blog post by Chris Shiflett about a crazy-creative SQL injection technique: http://shiflett.org/blog/2006/jan/addslashes-versus-mysql-real-escape-string

Very cool.  His technique relies on tricking addslashes into breaking up a two byte character with a slash, creating a valid two byte character followed by a valid one byte character.  He mentions that this (specific attack) is impossible with UTF-8 because all two (or more) byte characters have continuation bytes that start with 0b10.  Hrm.

Read more »