BCP for securing IPv6 Linux end node in AWS
Good morning all, I’m looking for some guidance on best practices to secure IPv6 on Linux end nodes parked in AWS. Boxes will be running various services (DNS for starters) and I’m looking to secure mainly ICMP at this point. Service filtering is fairly cut and dried. I’ve reviewed some of the stuff out there, but apparently I’m catching too many of the ICMP types in the rejection as routing eventually breaks. My guess is router discovery gets broken by too tight of filters. Thanks for any guidance. EKG
On dim. 14 mai 09:29:45 2017, Eric Germann wrote:
Good morning all,
I’m looking for some guidance on best practices to secure IPv6 on Linux end nodes parked in AWS.
Boxes will be running various services (DNS for starters) and I’m looking to secure mainly ICMP at this point. Service filtering is fairly cut and dried.
I’ve reviewed some of the stuff out there, but apparently I’m catching too many of the ICMP types in the rejection as routing eventually breaks. My guess is router discovery gets broken by too tight of filters.
Thanks for any guidance.
EKG
Hi, Filtering ICMP breaks Internet and it is even more true with IPv6 as almost all the bootstrap is based on ICMP (ND, RD, RA, etc.). Plus, you will break connections where there is a MTU change on the path. So, my advise is simply to not filter ICMP and ICMPv6. And by the way, why do want to filter ICMP? You will not be DDoSed with pings. -- alarig
The goal isn’t to filter _all_ ICMP. The goal is to permit ICMP that is needed for correct operation across the global network while protecting from externally spoofed packets. For example, on the IPv4 side, there arguably is no value to timestamp requests and address mask requests externally, so dump them. Thoughts? EKG
On May 14, 2017, at 9:42 AM, Alarig Le Lay <alarig@swordarmor.fr> wrote:
On dim. 14 mai 09:29:45 2017, Eric Germann wrote:
Good morning all,
I’m looking for some guidance on best practices to secure IPv6 on Linux end nodes parked in AWS.
Boxes will be running various services (DNS for starters) and I’m looking to secure mainly ICMP at this point. Service filtering is fairly cut and dried.
I’ve reviewed some of the stuff out there, but apparently I’m catching too many of the ICMP types in the rejection as routing eventually breaks. My guess is router discovery gets broken by too tight of filters.
Thanks for any guidance.
EKG
Hi,
Filtering ICMP breaks Internet and it is even more true with IPv6 as almost all the bootstrap is based on ICMP (ND, RD, RA, etc.). Plus, you will break connections where there is a MTU change on the path.
So, my advise is simply to not filter ICMP and ICMPv6. And by the way, why do want to filter ICMP? You will not be DDoSed with pings.
-- alarig
On 14 May 2017 at 16:49, Eric Germann <ekgermann@semperen.com> wrote: Hey,
For example, on the IPv4 side, there arguably is no value to timestamp requests and address mask requests externally, so dump them.
It's very dangerous proposal when we start considering everything 0 value which isn't value to ourselves currently. Is ICMP TS known attack vector? It has one particularly useful diagnostic purpose, you can use it to measure unidirectional latencies up-to 1ms accuracy. It has on occasions reduced needed troubleshooting time and reduced amount of people who need to look into the problem. -- ++ytti
Alarig Le Lay <alarig@swordarmor.fr> writes:
So, my advise is simply to not filter ICMP and ICMPv6. And by the way, why do want to filter ICMP? You will not be DDoSed with pings.
I tend to agree. But if you still want to do it, then there is some advice in https://tools.ietf.org/html/rfc4890 Bjørn
Hi Eric, in addition to RFC 4980 mentioned in another post you might consider the following sources as a starting point: https://insinuator.net/2015/12/developing-an-enterprise-ipv6-security-strate... https://insinuator.net/2015/12/developing-an-enterprise-ipv6-security-strate... https://www.troopers.de/media/filer_public/85/be/85bef719-59a4-4567-aebb-ce0... https://www.ernw.de/download/ERNW_Guide_to_Securely_Configure_Linux_Servers_... cheers Enno On Sun, May 14, 2017 at 09:29:45AM -0400, Eric Germann wrote:
Good morning all,
I???m looking for some guidance on best practices to secure IPv6 on Linux end nodes parked in AWS.
Boxes will be running various services (DNS for starters) and I???m looking to secure mainly ICMP at this point. Service filtering is fairly cut and dried.
I???ve reviewed some of the stuff out there, but apparently I???m catching too many of the ICMP types in the rejection as routing eventually breaks. My guess is router discovery gets broken by too tight of filters.
Thanks for any guidance.
EKG
-- Enno Rey ERNW GmbH - Carl-Bosch-Str. 4 - 69115 Heidelberg - www.ernw.de Tel. +49 6221 480390 - Fax 6221 419008 - Cell +49 173 6745902 Handelsregister Mannheim: HRB 337135 Geschaeftsfuehrer: Enno Rey ======================================================= Blog: www.insinuator.net || Conference: www.troopers.de Twitter: @Enno_Insinuator =======================================================
On Sun, May 14, 2017 at 09:29:45AM -0400, Eric Germann wrote:
I???ve reviewed some of the stuff out there, but apparently I???m catching too many of the ICMP types in the rejection as routing eventually breaks. My guess is router discovery gets broken by too tight of filters.
That's a good guess, but I would also guess that path MTU discovery may be breaking. (Or not.) I think you may want to implement RFC 4890, with a look at RFC 4443. ---rsk
Just make sure that nothing breaks PTB as it happens if you don’t pay attention to ECMP. RFC7690 1&1 in Germany has this issue since at least 18-24 months ago, so all their customers with IPv6 enabled are *broken* for anyone having a smaller MTU because tunnels or the ISP technology, etc. They are aware of that, I told them for many months, but is not yet fixed, so make sure you don’t use those data centers if you want to enable IPv6. You can check this with any of their IPv6 enabled sites (thousands I guess), for example http://diskmakerx.com/ And a nice tool to check it: https://nat64check.go6lab.si/ Regards, Jordi -----Mensaje original----- De: NANOG <nanog-bounces@nanog.org> en nombre de Rich Kulawiec <rsk@gsp.org> Responder a: <rsk@gsp.org> Fecha: lunes, 15 de mayo de 2017, 12:57 Para: nanog list <nanog@nanog.org> Asunto: Re: BCP for securing IPv6 Linux end node in AWS On Sun, May 14, 2017 at 09:29:45AM -0400, Eric Germann wrote: > I???ve reviewed some of the stuff out there, but apparently I???m > catching too many of the ICMP types in the rejection as routing eventually > breaks. My guess is router discovery gets broken by too tight of filters. That's a good guess, but I would also guess that path MTU discovery may be breaking. (Or not.) I think you may want to implement RFC 4890, with a look at RFC 4443. ---rsk ********************************************** IPv4 is over Are you ready for the new Internet ? http://www.consulintel.es The IPv6 Company This electronic message contains information which may be privileged or confidential. The information is intended to be for the use of the individual(s) named above. If you are not the intended recipient be aware that any disclosure, copying, distribution or use of the contents of this information, including attached files, is prohibited.
participants (7)
-
Alarig Le Lay -
Bjørn Mork -
Enno Rey -
Eric Germann -
JORDI PALET MARTINEZ -
Rich Kulawiec -
Saku Ytti