Re: Systemd vsock sshd

[Pat Gunn <pgunn01 () gmail com>]

There's another option; someone could reach out to the OpenSSH team and see
if they'd be open to having OpenSSH refuse to permit it without explicit
configuration, getting rid of the need to deal with the systemd project on
the topic, although what the systemd team may do in response to such a move
is anybody's guess. It's arguably within the OpenSSH project's scope if
because of the misdesign of systemd OpenSSH becomes part of an attack
vector for a lot of systems, and we know that the OpenSSH team takes
security seriously.

On Wed, 31 Dec 2025 at 01:04, Demi Marie Obenour <demiobenour () gmail com>
wrote:

> On 12/30/25 01:33, Jacob Bachmeyer wrote:
> > On 12/29/25 13:53, Greg Dahlman wrote:
> > > I did reach out to the systemd team, while I was working with the kernel
> > > security team and I encouraged others to do so if they think it will be
> > > productive.
> > >
> > > There are sensitivities and frustrations that span all groups that make
> > > that conversation difficult, but I think someone with an established
> trust
> > > with the project could make forward progress.
> >
> > I certainly agree that the systemd team's apparent "cavalier" attitude
> > towards security (and sound architecture) makes lots of frustrations.
> > (For example, the "katamari" architecture that made the xz-utils sshd
> > backdoor possible is definitely a bad practice, although a distressingly
> > common one not unique to systemd.)
> >
> > To *really* set things off here, this vsock listener that crosses what
> > is otherwise a security boundary *looks* like an attempt at a backdoor,
> > although I believe it to be ignorance/negligence rather than malice.
>
> If systemd *also* configured OpenSSH to only allow key-based login,
> this would be unexploitable unless OpenSSH has a vulnerability.
> --
> Sincerely,
> Demi Marie Obenour (she/her/hers)