[PATCH v8 0/8] Fork brute force attack mitigation

[Andi Kleen]

On 6/8/2021 4:19 PM, Kees Cook wrote:
> On Sat, Jun 05, 2021 at 05:03:57PM +0200, John Wood wrote:
>> [...]
>> the kselftest to avoid the detection ;) ). So, in this version, to track
>> all the statistical data (info related with application crashes), the
>> extended attributes feature for the executable files are used. The xattr is
>> also used to mark the executables as "not allowed" when an attack is
>> detected. Then, the execve system call rely on this flag to avoid following
>> executions of this file.
> I have some concerns about this being actually usable and not creating
> DoS situations. For example, let's say an attacker had found a hard-to-hit
> bug in "sudo", and starts brute forcing it. When the brute LSM notices,
> it'll make "sudo" unusable for the entire system, yes?
>
> And a reboot won't fix it, either, IIUC.
>
The whole point of the mitigation is to trade potential attacks against DOS.

If you're worried about DOS the whole thing is not for you.

-Andi