nanog mailing list archives

Re: Prefix hijacking, how to prevent and fix currently


From: Job Snijders <job () instituut net>
Date: Tue, 2 Sep 2014 17:25:39 +0200

On Tue, Sep 02, 2014 at 03:08:28PM +0000, Sriram, Kotikalapudi wrote:
The example that I gave was not that. In my example, C has legitimate
ownership of the less specific (e.g., 192.0.2.0/23).  D is malicious
and attempting to hijack a subprefix (e.g., 192.0.2.0/24).
Importantly, C has a created a ROA for 192.0.2.0/23 only to protect
its address space, but currently *does not advertise* this prefix or
any part of it.  So D's more specific announcement (hijack) is
'Invalid' in this scenario, but the 'Loose' mode operation would
accept/install D's route.  Am I right about that? If yes, that is the
side effect or CON that I was trying to highlight.

You are right in your observation.

What is the real damage of hijacking a prefix which is not in use?
Email reputation that gets trashed for that prefix? I think the hijacks
we fear most are those of prefixes that are actively in use. For these
attacks I'd want to help customers protect against, and unused space is
low on my priority list.

Further, at a later/more mature stage of RPKI, when most operators
have implemented the paragraph I cited from RFC 7115, then routers can
drop 'Loose' mode.

Implementing a 'Loose mode' would be a local policy decision, made by an
organisation, not a router. :-)

Kind regards,

Job


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