OpenBSD: A new feature added to the test snapshots of new versions of OpenBSD will create a single kernel whenever an OpenBSD user restarts or upgrades his computer.
Αυτή η λειτουργία ονομάζεται KARL από το Kernel Address Randomized Link, ή Τυχαία διεύθυνση του πυρήνα, και λειτουργεί με την επαναconnection (relinking) των εσωτερικών αρχείων πυρήνα με τυχαία σειρά, ώστε να δημιουργείται κάθε φορά ένα μοναδικό kernel binary blob.
Currently, in stable versions of OpenBSD the kernel uses a predefined order to perform relinking and load internal files into the kernel binary. This results in the same core for all of them users.
OpenBSD with KARL and not ASLR
KARL was developed by Theo de Raadt, and works by creating a new binary kernel during installation, upgrading, and boot time. If the user boots, upgrades or restarts his machine, a new created kernel will replace the existing kernel and the operating system will create a new binary kernel to be used in the next boot / upgrade / restart.
KARL should not be confused with ASLR or Address Space Layout Randomization, a technique which gives random memory address (memory address) when an application is executed. Thus exploits cannot target a specific area of memory that the attacker knows an application or the kernel is running.
Instead, KARL creates kernel binaries with random internal structures, so exploits can not attack internal kernel functions, pointers, or objects. A technical explanation is available in the link below.
http://undeadly.org/cgi?action=article&sid=20170701170044&mode=expanded&count=9
That's it feature developed in the last two months
Tasks for this feature began in May and were first discussed in mid-June through the OpenBSD technical mailing list. KARL was recently added to OpenBSD 6.1 snapshots.
This new feature appears to be unique in OpenBSD, as we do not know anything similar about it Linux.
Linux has just added support for the Kernel Address Space Layout Randomization (KASLR), a function that makes the ASLR port in the kernel itself, loading the kernel to a random memory address.
This feature was enabled by default on Linux 4.12, which was released last week. The difference between the two is that KARL loads different kernel binaries in the same place, while KASLR loads the same kernel binary at random locations. Same goal, different paths.
As for Windows, KARL is not supported, but Microsoft has been using KASLR for many years.
It should be mentioned that the new OpenBSD mode seems to provide much more security than the solutions used by Microsoft and Linux.
Perhaps after several tests we see KARL in other operating systems as well.
