White Hat

Most of the modern C compilers, like gcc, which are bundled in todays distros, have stack protection enabled. Sometimes, for security researchers like me, this can be a burden because we can't compile exploitable code, getting the following error:

*** stack smashing detected ***: ./vuln.o terminated

To disable stack protection during compile time, you need to pass the -fno-stack-protector argument:

gcc -fno-stack-protector -o vuln.o vuln.c

In this guide I will explain how to create a keypair (public/private key) and use them with FireGPG to encrypt/decrypt/verify your Gmail communications. What is GnuPG and what is FireGPG? GnuPG is GNU's tool for secure communication and data storage. It can be used to encrypt data and to create digital signatures. It includes an advanced key management facility and is compliant with the proposed OpenPGP Internet standard as described in RFC2440.

Before anything else, you will need to install GnuPG - if you are using a Debian/derivate Linux flavour, installing GnuPG is as simple as this:

Installing and using Nessus on a Debian/Ubuntu based system is as simple as following these steps:

sudo apt-get install nessusd nessus nessus-plugins

During the installation, it will ask you to create a Certificate, accept defaults, change location, state, etc if you like.

sudo update-rc.d nessusd defualts
/etc/init.d/nessusd start
sudo nessus-adduser

Using the loopback filesystem interface, you can create encrypted filesystems very easily. These filesystems are great for storing sensitive documents be it SSH or GnuPG keys, financial documents, etc.

To begin, you’ll need to load the aes and cryptoloop modules in the kernel if they are not already available. This can be done by executing:

# modprobe cryptoloop
# modprobe aes

Today I needed to find out where was my old workstation in the company. However I had forgot its IP address - the only thing I remembered is that I had an openssh server open. So I needed to scan all the subnet for that particular service (port 22). This is how I did it:

nmap -p 22 -P0 -sT 10.150.3.0/24

No, this article is not yet another database links tutorial. Sometimes you can have two databases, one being the live production database, and the other being a clone so that users can query the latter one (for security and load balancing reasons). So what does it involve to allow for example the finance unit access a particular schema on the live database through the clone database?