On Tue, Mar 5, 2019 at 4:54 PM <adamv0025@netconsultings.com> wrote:
Let me play a devil's advocate here, the above statement begs a question then, how do you know all that is harmful would you test for every possible extension and hw/sw permutation? So there would be 3 sets (though lines might be blurred) known safe, known harmful and the biggest of them unknown unknowns. Now as an operator of a commercial network (i.e. your customers like it mostly up) wouldn't you do a calculated risk evaluation and opt for the known safe -which you know 99% of your customers use and block the rest while pissing off the remaining 1%? I know it sounds awful (like a calculations for vehicle safety recalls), but ...
You don't know. Everything is horribly broken anyhow and if you are not pwned, the main reason is that you're not attractive target. If you are being targeted, you will be pwned by zero to modest budget. Attacker budget leverage to defender is ridiculous. And ICMP won't be the vector. Fear is excellent marketing tool, as we can see in politics, works every time. But I rather fix realised problems, rather than make unprovable assumptions of actions yielding to net benefit. The assumption here is, if we just allow ICMP types A, B and C we are gaining in security, can we substantiate that claim at all? We can substantiate easily that the proposed ICMP filter breaks real useful ICMP tooling. -- ++ytti