Première édition de recon en Belgique en ce début d’année! Le logo de l’évènement change, mais le programme reste le même: Reverse engineering et exploitation. Du coup, pas une seule conférence n’a oublié son screenshot d’IDA Pro (qui est d’ailleurs le sponsor de l’évenement). Comme pour l’édition 2016 de Montréal, les conférences ont duré trois jours avec une seule track, donc pas de remords ni de regrets. 🙂
Je vous propose un aperçu de quelques conférences de cette première édition Européene:
In this post I describe a detailed solution to my “winworld” challenge from Insomni’hack CTF Teaser 2017. winworld was a x64 windows binary coded in C++11 and with most of Windows 10 built-in protections enabled, notably AppContainer (through the awesome AppJailLauncher), Control Flow Guard and the recent mitigation policies.
On October 25th, Joomla! was updated to version 3.6.4 to address two vulnerabilities :
CVE-2016-8869 concerning registration with elevated privileges. CVE-2016-8870 concerning account creation while registration is disabled.
In this post, we wanted to quickly discuss the vulnerability and its impact on vulnerable installations.
Upon patch-diffing the two versions, we noticed that an entire method had been removed from the components/com_users/controllers/user.php file : the register method from the UsersControllerUser class.
Normally, the register method used by Joomla! is the one from the UsersControllerRegistration class, in components/com_users/controllers/registration.php.
The deleted one is most likely a leftover from old patches, and doesn’t enforce a check on whether or not user registration is enabled (as opposed to the UsersControllerRegistration.register method).
Moreover, the $data array is supposed to be sanitized in the first line below, but the unsanitized value is then used in the register function at the end of this snippet, allowing us to submit custom data such as group and uid values.
We can call this method by posting our registration values on the index.php?option=com_users&task=User.register URL.
The newly created user is then found on the server :
For a valid request, we need to retrieve a CSRF Token and post it with a value = 1.
We are able to specify a custom user[id] value. If that id pre-exists in the database, the corresponding user will be overwritten during the registration.
Additionally, we can get high privileges by posting an array of user[groups][] values that will be assigned to the account. The default group id for Administrators is 7.
La Cybsec16 est maintenant terminée et toute l’équipe SCRT présente a de nouveau passé un bon moment en compagnie de différents acteurs du monde de la sécurité en suisse romande (et un peu au delà). Une excellente organisation, des conférences intéressantes et diversifiées ainsi que les divers events “networking” ont largement contribué au succès de l’événement.
Première fois à recon et, oh waww! Assez différente des autres conférences, recon (dont le site web est recon.cx et non recon.com) est fortement orientée sur le Reverse Engineering et l’exploitation, que ce soit hardware ou software.
Étalée sur 3 jours avec une seule track, la conférence est pleine de talks à la fois intéressants et hallucinants, que nous tentons donc de résumer dans ce long post!
Last weekend saw the year’s CTF competitions begin with our very own Insomni’hack teaser. Given some of the recent absurdities (http://weputachipinit.tumblr.com/) we decided to go with the Internet of Things as our theme this year.
At the recent BlackHat Europe conference (November 10 – 13, Amsterdam) a security researcher called Ian Haken presented a very interesting, simple yet powerful attack allowing to bypass Windows (Kerberos) authentication on machines being part of a Domain.
