Let's encrypt certificate for offline servers with OVH DNS

Let's encrypt provide free and easy SSL certificates. Nevertheless it need to verify that you own the machine. In order to do that we usually use HTTP verification with the .well-known directory.

But sometime our servers are not reachable from the internet. Therefore the HTTP validation is not possible. Hopefully there is another way the acme challenge can be validated: DNS validation.

In this post we will see how we can generate Let's encrypt SSL certificate for offline machine with DNS validation for domains hosts by OVH.

CVE 2016-5195 dirtycow

Ðirtycow logo

Dirty COW (CVE-2016-5195) is a privilege escalation vulnerability in the Linux Kernel. "A race condition was found in the way the Linux kernel's memory subsystem handled the copy-on-write (COW) breakage of private read-only memory mappings. An unprivileged local user could use this flaw to gain write access to otherwise read-only memory mappings and thus increase their privileges on the system." (Source: Red Hat)

CVE 2016-6210 OpenSSHD user enumeration

The 13th if July a new wild CVE appeared (Yes, Pokemon Go is still a buzz for the moment).

The CVE 2016-6210 allow a user enumeration on an SSH server by comparing request time between non existing user and allowed ones. This vulnerability target OpenSSHD with a version of 7.2p2 or inferior.

That means with a good dictionary you may know which user are present on the server with an SSH access.

This post just demonstrate how to exploit this vulnerability with a simple example.

Vulnhub Droopy

Droopy homepage A few days ago, I installed a new pentesting box based on Arch Linux with Kali

in a virtual machine. In order to test it I select a light vulnbox on vulnhub : Droopy. There were two hints on the description of the machine on the vulnhub download page:

  1. Grab a copy of the rockyou wordlist.
  2. It's fun to read other people's email.

We will see how to use them in a moment :)

Installing OSMC without installer

I bought the new raspberry pi 3 with integrated Wi-Fi. Currently I still have a Ethernet cable running through my living room to my old raspberry pi 1.

Just willing to download the last raspbmc version I figured that it was no more raspbmc but osmc which is basically the same but with much marketing around it. The most annoying one is that you need to install an install (such meta). I was pretty much sure it was not really necessary and moreover there is no version of the installer for Arch Linux.

Vulnhub - FlickII


Still playing with the vulnhub machines this time it is the turn of FlickII. This one is different from the others as it has an android application associated. It would be a great exercice to play with mobile application, decompile it and see what is in the inside.