Re: rsync and RPKI Validation

[Geoff Huston <gih () apnic net>]

> On 9 Sep 2022, at 4:36 pm, Vincent Bernat <bernat () luffy cx> wrote:
>
> On 2022-09-09 04:56, Matt Corallo wrote:
> > Has anyone done an analysis of the rsync CVE-2022-29154 (which "allows malicious remote servers to write arbitrary 
> > files inside the directories of connecting peers") and its potential impact on RPKI validators? It looks like both 
> > Debian [1] and Ubuntu [2] opted *not* to patch rsync in their release/security package streams.
> > Are rsync-based (or rsync-fallback, which I believe is still required for all RPKI validators?) RPKI validators all 
> > vulnerable to takeover from this, or is there some reason why this doesn't apply to RPKI validation?
>
> The attacker is still limited to the target directory. The attacker can send files that were excluded or not 
> requested, but they still end up in the target directory. RPKI validators download stuff in a dedicated download 
> directory (but it may be shared with several peers), so they should be safe.

If the topic is whether rsync is fit for purpose for the RPKI I’d like to reference a still relevant presentation from 
IETF 89: https://www.ietf.org/proceedings/89/slides/slides-89-sidr-6.pdf As far as I am aware the issues raised in this 
presentation remain current.

My takeaway from that presentation is that there is some simple advice about using rsync in the context of the RPKI 
cache sync operation: don’t.

thanks,

 Geoff