nanog mailing list archives

Re: [EXTERNAL] Re: Help with removing DNS shinkhole FP from Charter/Spectrum


From: Validin Axon <axon () validin com>
Date: Tue, 23 Apr 2024 17:14:12 -0400

Thank you, Jim. Who is the vendor responsible?

Kenneth

On Tue, Apr 23, 2024 at 4:24 PM Rampley, Jim F <jim.rampley () charter com>
wrote:



Hi Kenneth,



We have been working internally and with our third-party domain reputation
source to get your domain removed from their malware list.



Jim



*From: *NANOG <nanog-bounces+jim.rampley=charter.com () nanog org> on behalf
of Validin Axon <axon () validin com>
*Date: *Tuesday, April 23, 2024 at 2:15 PM
*To: *Tom Beecher <beecher () beecher cc>
*Cc: *NANOG <nanog () nanog org>
*Subject: *[EXTERNAL] Re: Help with removing DNS shinkhole FP from
Charter/Spectrum



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Tom,



Thank you for this! It is very interesting that the behavior is
intermittent. A friend of mine who tested it this weekend saw correct
answers on IPv6 and incorrect answers on IPv4.



Kenneth



On Tue, Apr 23, 2024 at 2:56 PM Tom Beecher <beecher () beecher cc> wrote:

Validin, made an interesting observation on this. I am also a Spectrum
residential customer,  none of their equipment, run my own DNS server
(pihole).



My DHCP Assigned DNS servers are

2001:1998:f00:1::1
2001:1998:f00:2::1

bash-3.2$ dig -x 2001:1998:f00:1::1 +short
dns-cac-lb-01.rr.com.
bash-3.2$ dig -x 2001:1998:f00:2::1 +short
dns-cac-lb-02.rr.com.
bash-3.2$


bash-3.2$ dig dns-cac-lb-01.rr.com +short
209.18.47.61
bash-3.2$ dig dns-cac-lb-02.rr.com +short
209.18.47.62
bash-3.2$

bash-3.2$ dig @209.18.47.61 validin.com +short
157.245.112.183
137.184.54.107
bash-3.2$ dig @209.18.47.62 validin.com +short
157.245.112.183
137.184.54.107
bash-3.2$

bash-3.2$ dig @2001:1998:f00:1::1 validin.com +short
127.0.0.54
bash-3.2$

bash-3.2$ dig @2001:1998:f00:2::1 validin.com +short
127.0.0.54
bash-3.2$

Same servers on V4 were returning correct info, but on V6 were not.

However, a few minutes later :

bash-3.2$ dig @2001:1998:f00:1::1 validin.com +short
157.245.112.183
137.184.54.107
bash-3.2$ dig @2001:1998:f00:2::1 validin.com +short
157.245.112.183
137.184.54.107
bash-3.2$

Deltas :

bash-3.2$ dig @2001:1998:f00:1::1  validin.com

; <<>> DiG 9.10.6 <<>> @2001:1998:f00:1::1 validin.com
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 42329
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0

;; QUESTION SECTION:
;validin.com.                   IN      A

;; ANSWER SECTION:
validin.com.            60      IN      A       127.0.0.54

;; Query time: 37 msec
;; SERVER: 2001:1998:f00:1::1#53(2001:1998:f00:1::1)
;; WHEN: Tue Apr 23 13:50:03 EDT 2024
;; MSG SIZE  rcvd: 45

bash-3.2$

bash-3.2$ dig @2001:1998:f00:1::1 validin.com

; <<>> DiG 9.10.6 <<>> @2001:1998:f00:1::1 validin.com
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 9667
;; flags: qr rd ra; QUERY: 1, ANSWER: 2, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 512
;; QUESTION SECTION:
;validin.com.                   IN      A

;; ANSWER SECTION:
validin.com.            600     IN      A       157.245.112.183
validin.com.            600     IN      A       137.184.54.107

;; Query time: 157 msec
;; SERVER: 2001:1998:f00:1::1#53(2001:1998:f00:1::1)
;; WHEN: Tue Apr 23 14:19:20 EDT 2024
;; MSG SIZE  rcvd: 72

bash-3.2$



Seems like quite possibly they are intermittently caching bunk data from
something.





On Tue, Apr 23, 2024 at 1:39 PM Validin Axon <axon () validin com> wrote:

Hi Jason,



I suspect what’s happened is an incorrect assumption that DNS is even
the issue here. Because you mentioned Spectrum Shield, I suspect it is not.



I appreciate the response and links. However, I've been told repeatedly by
Spectrum that they're not blocking with Spectrum Shield. Despite these
assurances, I've filled out a removal request through their published
removal process several times, and the response I received stated that
we're not being blocked. This check agrees with that:

https://www.spectrum.net/support/forms/verify_url_security



"Security Shield Is Not Blocking This Site

The URL provided is not being blocked by Spectrum Security Shield
The URL you entered should be accessible."

Further, checking Spectrum DNS servers on the Spectrum network show that
my company's main domain and all subdomains resolve to 127.0.0.54. So, if
CujoAI/Spectrum Shield are not using DNS query responses to control access,
then it's not CujoAI/Spectrum Shield that is responsible for the incorrect
DNS response. Using a different recursive resolve, I can resolve our
domains just fine. I can also resolve other domains that point to the same
IPs as the sinkholed domain just fine. However, many people use the
Spectrum default DNS servers and cannot access my website because of this.



You should contact Charter/Spectrum to have them investigate what their
system might be blocking this content.



I have tried, for months, including spending many hours on chat and phone
support, to reach someone within Spectrum support who is capable of both
understanding and directing me to someone who can fix the problem, but it
hasn't happened yet. I've asked to talk to someone on the DNS team and was
given a flat "No." I've posted here hoping that someone in the
ISP-connected world knows SOMEONE at Spectrum, Akamai, or whichever company
is actually responsible for the Spectrum DNS servers who can provide a
remediation path.



Regards,



Kenneth



On Tue, Apr 23, 2024 at 12:59 PM 'Livingood, Jason' via axon <
axon () validin com> wrote:

However, there's no correction process for Spectrum's DNS sinkhole

But back to the topic: someone mentioned to me that Spectrum may not be
the direct providers for the DNS services they provide to their customers.
If anyone knows anything about how I might discover and reach out to the
people responsible, please let me know.



I suspect what’s happened is an incorrect assumption that DNS is even the
issue here. Because you mentioned Spectrum Shield, I suspect it is not.

Spectrum Shield (
https://www.spectrum.com/resources/internet-wifi/benefits-of-spectrum-security-shield)
is a customer-managed security protection service built into their gateways
(I assume you can turn it off). The malware and content detection engine
behind that is very likely run by CujoAI (https://cujo.com/) and it does
not use DNS query/response exchanges as the control mechanism (in part to
counter-act DNS-changing malware or malware using its own DoH channel for
example).

You should contact Charter/Spectrum to have them investigate what their
system might be blocking this content.

Comcast (where I work) runs a similar system (
https://www.xfinity.com/support/articles/using-xfinity-xfi-advanced-security)
and maintains a site to report these sorts of issues (
https://www.xfinity.com/support/articles/report-blocked-website).

Jason









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