Christophe Tafani-Dereeper

[Write-up] Vulnix – playing around with NFS

christophetd 6 October 2017 6 April 2017 1 Comment

I managed to find the time to play on a new vulnerable VM. This time, it will be Vulnix and will mainly be around exploiting vulnerable NFS shares. The VM was overall quite simple, but still learned me several things about NFS and how it plays with remote permissions.

[Write-up] Mr Robot

christophetd 12 January 2018 4 April 2017 23 Comments

It’s been a few months since I wrote my last write-up on a VulnHub vulnerable machine. Time for a new one! The VM is called Mr Robot and is themed after the TV show of the same name. It contains 3 flags to find, each of increasing difficulty.

[Write-up] Droopy v0.2 CTF

christophetd 11 April 2017 20 January 2017 1 Comment

I recently started gaining a lot of interest in security, and after reading several CTF write-ups, I decided to try to solve one by myself. I chose Droopy v0.2. In case you don’t know, the goal of a CTF is very simple: Capture The Flag! Most of the time, the flag is simply a text file that you can obtain after having gained root access on the machine. You are only provided with a virtual machine, and the rest is up to you. Let’s get started!

git bisect for the win

christophetd 5 June 2017 27 November 2016 Leave a Comment

I recently discovered the git bisect command. At first I thought « meh, this is just another obscure git command I’ll never use » but it actually turns out I used it several times in the last week and it saved me a non negligible amount of time. I’m therefore writing this post to make a quick introduction to git bisect.

How to setup a SFTP server with chrooted users

christophetd 5 June 2017 16 October 2016 5 Comments

I’ll explain in this article how to properly setup a SFTP server with chrooted users being only able to access their own directory, and authenticated by public keys or a password. This is a very useful setup, which can get a bit tricky especially with the permissions. Unlike FTPS which is FTP over TLS, SFTP is a totally different protocol built on top of SSH. This especially means you don’t need any third-party software, since OpenSSH is installed by default on most linux distributions.

Quickly access your configuration files on your server

christophetd 11 April 2017 29 September 2015 Leave a Comment

It’s been a while since I last wrote a post on this blog, so I’ve decided to share a simple way to quickly access the configuration files of the numerous services you may be running on your server. It is indeed quite painful to frequently edit arbitrary deep configuration files (such as /etc/php5/apache2/php.ini) that are spread out in your file system and which you don’t remember the names. The trick I am using is a directory named cfg at the root of my server, in which I create symbolic links pointing to configuration files or directories containing them, with names that are easier to remember.