[ntp:questions] hacking NTP autokey with / without IFF

manel_torralba at mail.com manel_torralba at mail.com
Sun Jan 9 23:34:44 UTC 2005

Hi all,

I am trying to understand correctly the autokey NTP security schemas.
Could somebody verify if the following scenarios are right, and if
wrong, why ?

Basically , let´s suppose there is a simple scenario with S as the
single ntp server and C as the "interesting" ntp client, say, a
Certificate Authority in a PKI. And we have our fiend R, a rogue server
whose goal is to get C´s client wrong.

Scenario 1: S and C use Autokey but no IFF (or any other identity
- R kills S and takes over its IP (or some similar scenario without
killing S, but via manipulation of an intermediate router).
- R makes sure it has S´s hostname and generates the ntp-keygen -T
- C synchronizes with R. C´s time is hacked.

Scenario 2: S and C use Autokey + IFF.
- R steals the IFF group key. He can steal it from any of S´s clients
or from S itself.
- R installs the IFF group key.
- Rest of the steps as above (killing of S, etc..)

Please note that I am not evaluating how good or bad this is as a
security model... I am only trying to make sure I understood it
correctly (or maybe not, but where am I mistaken?).
Thanks everyone in advance,

Manel T.-

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