Wed, 09/08/2021 - 12:59Usually we don't do blog posts about CTF challenges but we recently stumbled across a challenge that was a good opportunity to talk about several macOS/iOS internals, security mechanisms and exploit methods...
Thu, 09/02/2021 - 12:00Among targets for the Pwn2own Tokyo 2020 was 2 NAS, the Synology DiskStation DS418play and Western Digital My Cloud Pro PR4100. We took a look at both, and quickly found out Western Digital PR4100 was vulnerable via its webserver. However, exploitation was not THAT easy (it was not that hard either) and ultimately it did not even mattered since the vulnerability was wiped by a major OS update pushed mere days before the contest. In the end, the vulnerable code we audited might not have even been written by Western D...
Mon, 08/02/2021 - 13:01Synacktiv participated in the first edition of the HackTheBox Business CTF, which took place from the 23rd to the 25th of July. The event included multiple categories: pwn, crypto, reverse, forensic, cloud, web and fullpwn (standard HTB boxes). We managed to get 2nd place after a fierce competition. We had quite a lot of fun so we decided to publish write-ups of the most interesting challenges we solved.
Fri, 07/30/2021 - 09:11This is the last part of series, where we solve the challenge using our symbolic interpreter, and an external SMT solver. Huge success!
Wed, 07/28/2021 - 10:00In this installment, we turn the concrete interpreter into a symbolic interpreter. How exciting!
Fri, 07/23/2021 - 10:05In the second part of this series, we write a concrete interpreter for a subset of WebAssembly.
Mon, 07/19/2021 - 19:01Writing a symbolic interpreter, and wiring it to a solver in order to solve reverse engineering challenges (or other uses), might seem like a daunting task. Even simply using an existing symbolic interpretation framework is far from easy when one has no experience in it. This serie of articles will describe, throughout the summer, how such an engine is built, and showcase implementation tricks and some trade offs to be aware off. Do not worry, the interpreter will be kept as simple as possible though! In the end, we...
Tue, 07/13/2021 - 15:10This year again, the international contest Pwn2Own Vancouver took place in the beginning of April. Among the different categories, two major operating systems were suggested for the Local Escalation of Privilege category (LPE): Linux (Ubuntu) and Windows 10. This article describes how a Ubuntu kernel vulnerability was found and exploited during this contest allowing to gain root access from an unprivileged user.
Tue, 06/01/2021 - 15:56Mojolicious is a Perl framework for web development we have recently encountered during one of our missions. Mojolicious handles cookies using a JSON string signed using HMAC-SHA1. The format reminds JWT. This article describes how the cookie signature is done by Mojolicious and how to crack it in order to generated valid cookies.
Fri, 05/28/2021 - 12:00You probably already have encountered document converting features that deal with ImageMagick during engagements but for some reason you were not able to exploit them. This article will mention some techniques that could be used when an older version of ImageMagick is targeted. Spoiler alert: this is not new.