Posts with label "security"

Breaking some homemade crypto

I recently did a code review assessment on an application for one of my client. The best part of the application was their own cryptography algorithm.

Moreover, the application was written in PHP and PHP do some strange things with string, characters and XOR operations. It only needed a few lines of python in order to break it.

TL;DR : please do not write your own crypto!

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 :)

Vulnhub - FlickII

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.

Auditing Exchange Server

ExchangeAnalyser

Recently I performed a MS Exchange configuration review. For the "old" version of exchange we can use the Microsoft Exchange Best Practices Analyzer. For the new version of MS Exchange (2013 and 2016) the tools must be download from the office 365 market. But most of the MS Exchange server are not directly connected to internet. That is why I used a tool developed by Paul Cunningham: Exchange Analyzer available on github.