A strange behavior was observed by Synacktiv experts during the security assessment of a stateful firewall implementation... After few coffees & RFCs it was understood that it could be a generic issue that might affect multiple IP stacks. So... What is a strange firewall behavior ? This article presents an implicit behavior of Linux nftables and OpenBSD PacketFilter? regarding the filtering of ICMP and ICMPv6 packets we considered as a security issue. It allows an attacker to bypass filtering rules in some cases an...

Code Check(mate) in SMM

In this article, a bypass of the SMM_CODE_CHK_EN, the equivalent of the SMEP protection for the System Management Mode (SMM), protection is explained. This article first explain the protection and the bug class it impacts, then the idea of the bypass is detailed and a leak is explained for being able to make it work.

Binder transactions in the bowels of the Linux Kernel

Binder is the main IPC/RPC (Inter-Process Communication) system in Android. It allows applications to communicate with each other and it is the base of several important mechanisms in the Android environment. For instance, Android services are built on top of Binder. Message exchanged with Binder are called binder transactions, they can transport simple data such as integers but also process more complex structures like file descriptors, memory buffers or weak/strong references on objects.

Kinibi TEE: Trusted Application exploitation

This blog post is dedicated to the Trustonic's TEE implementation and more particularly to the integration made by Samsung for its Exynos chipsets. Samsung recently patched a trivial vulnerability in a Trusted Application. After a brief explanation of TrustZone/Kinibi, this article details the exploitation of this vulnerability.

E-ink maiden: Bring your reader to the reverser

As a team of security researchers, we like poking at software and tinkering with common household objects for fun. So, one of our researchers bought an electronic paper reader tablet, and instead of reading ebooks on the train, started having fun with it!