>>6559>>6540The NSA's backdoor into OpenBSD's Compiler and Kernel
The backdoor was initially introduced using compiler backdooring, which involves modifying the code of a compiler itself to introduce a backdoor into the output executable. In this case, the backdoor was added into the clang compiler, which is used to compile C and C++ code on OpenBSD.
To introduce the backdoor, the NSA used TCP 0day exploits to gain access to the OpenBSD network and modify the binary of the clang compiler on an OpenBSD development server to cause the backdoor to spread into any compiled programs which on execution would infect the system's clang with the same backdoor, as well as adding a new function that could be used to execute arbitrary code with root privileges. They also added a trigger condition to the code that would activate the backdoor only when certain conditions were met, such as upon recieving a specific network packet.
Once the backdoor was added to the compiler code, it was compiled and included in the OpenBSD kernel and other parts of the operating system. This made it incredibly difficult to detect, as the backdoor code was hidden among legitimate code.
The NSA went even further and managed to replicate the backdoor in the BIOS firmware of affected systems. This was accomplished by distributing several BIOS 0day exploits using the original backdoor onto the systems, installing the same backdoor payload as the compiler and kernel onto the system's BIOS image.
The BIOS payload was designed to execute the backdoor code during the system boot process, before the operating system had loaded. This allowed the backdoor to remain fully persistent, even if the hard drive was wiped and the operating system was reinstalled.
The firmware payload was added to a specific area of the BIOS that is not typically overwritten during a standard BIOS update or reflash.
It's also worth noting that this exploit is not limited to OpenBSD or even the x86 architecture, and could potentially be present on many more platforms than we currently know of
Overall, the NSA's backdoor in the OpenBSD clang compiler and kernel, and its replication in the BIOS firmware, represents a serious threat to privacy and security. The techniques used to introduce and replicate the backdoor are incredibly advanced and difficult to detect, and nearly impossible to remove without the replacement of hardware.
https://marc.info/?l=openbsd-misc&m=143355112811564