Newbie Questions: How-to monitor/control unauthorized uses of our IPs and DNS zones?

Thu Aug 19 18:32:16 UTC 2021

Huh.
And I thought that I did lay down information (and questions) pretty
clearly, but as you correctly pointed out, I didn't.
So, here goes the second version:

Background Information Section (v2):
We are a Registrant and already registered a zone/domain with a Registry,
we are also a LIR and have been allocated an IP block straight from RIR.
[What I meant to say is that they all keep saying that we don’t “own” those
resources and we also have to pay the annual fee so, even though we are a
Registrant and a LIR, it’s still practically a form of rent anyway.]
We DNSsec-sign and host both forward and reverse zones ourselves, with
NSEC3 to prevent zone enumeration.
We register our IP block on both IRR and ROA, and constantly monitor them
both for poison records.

Here’s the sticky part:
We have ‘jurisdiction’ over all those things above.
But: the Web Server part---hardware, software, and content---belongs to the
‘other department’. That’s my fact-of-life; can’t change it. [Does anyone
have this same ‘arrangement’? Or do you guys rule over everything?]
Second but: ‘they’ want me to prevent anyone from using organization
resources---IPs, hostnames, web server hardware/software---without asking
permission; essentially asking me to look over the web admins’ shoulders.

I know for a fact that some websites with FQDN outside our zone have A/AAAA
records with addresses from my IP block.

On the other hand, some other websites offload contents onto our servers.

Question Section (v2):
Since I am not the web admin:
1. How-to monitor whether some outsiders are putting our IP addresses into
their A/AAAA records without me knowing about it?
2. How-to monitor whether some outside websites are just ‘shells’, with
contents actually being hosted by our servers without me knowing about it?

-- 
Pirawat.

On Thu, Aug 19, 2021 at 9:45 PM Bill Woodcock <woody at pch.net> wrote:

>
>
> > On Aug 19, 2021, at 4:05 PM, Pirawat WATANAPONGSE via NANOG <
> nanog at nanog.org> wrote:
> > Background Information Part:
> > We rent an IP Address Block and a DNS zone.
> > [We have to pay the annual fees, so they are renting, yes? :-) ]
>
> We don’t have enough information to know whether you’re renting or are the
> registrant, based on what you’ve said.
>
> If you receive your domain name from a registrar, and the whois shows you
> to be the registrant, you’re the registrant.  If you have a subdomain or
> you pay “rent” to someone who is shown as the registrant in the whois, then
> you’re just renting.
>
> Likewise, if you receive your IP addresses from a regional Internet
> registry (ARIN in the NANOG region), you’re the LIR, or Local Internet
> Registry.  If you have a subnet (which may be SWIPped into the whois, or
> may not) which you received from an LIR, then you’re just renting.
>
> > We run our own DNS authoritative server, with DNSsec on.
>
> Meaning that you’re DNS signing both the forward (A/AAAA) and reverse
> (in-addr/ip6) zones?
>
> > Authority over DNS records, ROAs, and BGP table are with us, but
> authority over the Web Servers are (naturally) not.
>
> It’s not clear what you mean by this.  You mean that you don’t operate
> your own web servers, but instead use an outsourced service, which in turn
> uses its own IP addresses?
>
> > Question Part:
> > 1. How (or where) can I monitor/control such that no one can ‘map’ my IP
> addresses to external FQDNs [hijacking my IPs] without me knowing about it?
>
> These are separate and unrelated things.
>
> Hijacking your IP addresses would be originating BGP announcement of
> them.  Which other people should not do, and other people should not pay
> attention to if they’re validating ROAs and IRR entries.
>
> Mapping your IP addresses to domain names (in-addr/ip6) is not an
> effective attack vector, and nobody will pay attention to anyway, if you’re
> the authoritative delegate for those blocks.
>
> Mapping domain names to IP addresses (A/AAAA) is not an effective attack
> vector, and anyone can do, without disrupting anything.
>
> > 1.1. My understanding is that, as long as I control the authoritative
> (DNSsec)server and people out there validate the DNS responses, hijacking
> my IPs outright for use somewhere else is (theoretically) impossible, yes?
>
> If someone else conducts an effective DNS hijacking attack, intermediating
> themselves between your users and your servers, and your users don’t DNSSEC
> validate, then the attack will be successful.  If your users do DNSSEC
> validate, AND THE APPS AND OSES THEY USE DON’T CIRCUMVENT IT, then the
> attack will fail.  But that’s a big if.  Many apps and OSes prefer a MITM
> attacker to a DNSSEC validation failure, because support costs.
>
> > 2. But, web admins can still essentially ‘rent out’ part or whole of my
> websites by hosting 'forreign' pages/codes and allowing in ‘external
> redirection’ from outside (to use my hardware! my IPs!) anyway, yes?
>
> If by “web admins” you mean third parties, rather than people who are
> responsible to you, yes.  Which is why people concerned with security host
> their own services.
>
> > 3. How (or where) can I monitor/control such that no one can ‘map’ FQDNs
> from within my DNS zone to external IP addresses [hijacking my hostnames]
> without me knowing about it?
>
> There are at least three possibilities here.
>
> One is that someone has access to the unsigned zone data below your
> delegation, in which case this is an internal security problem.  If you’re
> using NSEC3 to prevent zone enumeration, and it were occurring in a
> delegated subdomain, this might actually be a difficult problem.
>
> The second possibility is that someone external to your organization, who
> has access to DNS traffic flows (client, recursive, etc.) interposes
> themselves as a MITM or injects false data into a resolver cache. You
> could, hypothetically, buy access to “passive DNS” feeds which might reveal
> some portion of such traffic, if it existed, but that’s a very long shot.
>
> A third (and probably most likely) possibility is that someone hijacks
> your domain at the registrar level, because registrars generally have crap
> security and fall over all the time, and registrants routinely use crap
> passwords to secure their accounts with registrars, etc.  They could then
> add an additional nameserver, or substitute in all of their own
> nameservers.  At that point, their actions would be fairly visible, and
> they’d still have to do a dirty roll of the DNSSEC KSKs, if they wanted to
> make things validate, but most wouldn’t bother doing so.  There are
> monitoring services which watch for nameserver changes, but all the ones
> I’ve seen don’t actually check as often as they say they do, so miss
> attacks of this sort that are done quickly.
>
> > 3.1. My understanding is that, web admins can write all sorts of
> ‘redirect’ in such a way that parts or even my whole websites can be
> ‘hosted’ on external IPs/hardware, yes?
>
> Yep.  See “why you shouldn’t do that” above.
>
> > 4. Does that mean I need a big Web Application Firewall (WAF)
>
> Absolutely not.  I have no idea what a Web Application Firewall is, but if
> it’s anything like it sounds like, I wouldn’t let one anywhere near
> anything I was responsible for securing.
>
> > The thing is, no one should be able to use organization resources [IPs,
> FQDNs, and Web Services, for a start] for his/her own purpose without
> asking permission.
>
> Sounds like you’re going to be writing a lot of shell scripts and cron
> jobs.  Welcome to security.  Remember to test your backups, that’s always
> the most important thing in any security regime.
>
>                                 -Bill
>
>
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