nanog mailing list archives

Re: RESOLVED: Cogent Abuse - Bogus Propagation of ASN 36471


From: Pete Rohrman <prohrman () stage2networks com>
Date: Thu, 20 Jul 2023 17:20:27 -0400

Matt/Giorgio,

See my answers inline to Matt's line of questioning below, but the basics are that those prefixes and AS number were owned by S2NL and used for years.  After all the employees were let go (including me), this router in question was compromised, and the ssh and enable were changed.  Don't know who did it.  ARIN re-assigned the AS and prefixes to other parties.  A few days ago, the new AS owner found me from an ARIN registration, and asked for my assistance to cease advertising AS36471.  I opened tickets with Cogent to turn it down, to learn that I was removed from the ability to make such radical requests.  I was just trying to be a good internet citizen by assisting in sorting this out.  It's resolved now.  Thank you for the help.

Pete
Stage2 "Survivor Island" Bronze Medal Winner



On 7/20/23 13:33, Giorgio Bonfiglio wrote:
Do you mind following up on Matthew’s request for details - really interested to see the threat model there and how the RPKI part played out?

On 20 Jul 2023, at 18:06, Pete Rohrman <prohrman () stage2networks com> wrote:



All,


Cogent has shut down the compromised router.  This issue is resolved.  Thank you all for your help.



Pete
Stage2 "Survivor Island" Bronze Medal Winner



On 7/20/23 12:59, Mike Hammett wrote:
If they (or anyone else) want to give me free service to use as I see fit (well, legally), I'll gladly accept their offer.



-----
Mike Hammett
Intelligent Computing Solutions
http://www.ics-il.com

Midwest-IX
http://www.midwest-ix.com

------------------------------------------------------------------------
*From: *"Tom Beecher" <beecher () beecher cc>
*To: *"Matthew Petach" <mpetach () netflight com>
*Cc: *nanog () nanog org
*Sent: *Thursday, July 20, 2023 11:38:50 AM
*Subject: *Re: Cogent Abuse - Bogus Propagation of ASN 36471

    In short--I'm having a hard time understanding how a non-paying
    entity still has working connectivity and BGP sessions, which
    makes me suspect there's a different side to this story we're
    not hearing yet.   ^_^;


I know Cogent has long offered very cheap transit prices, but this seems very aggressive! :)

On Thu, Jul 20, 2023 at 12:28 PM Matthew Petach <mpetach () netflight com> wrote:



    On Thu, Jul 20, 2023 at 8:09 AM Pete Rohrman
    <prohrman () stage2networks com> wrote:

        Ben,

        Compromised as in a nefarious entity went into the router
        and changed passwords and did whatever.  Everything
        advertised by that comprised router is bogus.  The
        compromised router is owned by OrgID: S2NL (now defunct). 
        AS 36471 belongs to KDSS-23
        <https://search.arin.net/rdap?query=KDSS-23&searchFilter=entity>.
        The compromised router does not belong to Kratos KDSS-23
        <https://search.arin.net/rdap?query=KDSS-23&searchFilter=entity>,
        and is causing routing problems.  The compromised router
        needs to be shut down. The owner of the compromised router
        ceased business, and there isn't anyone around to address
        this at S2NL.  The only people that can resolve this is
        Cogent. Cogent's defunct customer's router was compromised,
        and is spewing out bogus advertisements.

        Pete



    Hi Pete,

    This seems a bit confusing.

    So, S2NL was a bill-paying customer of Cogent with a BGP
    speaking router. _<< YES, and they used to own AS36471 and used
    it for years>>_
    They went out of business, and stopped paying their Cogent
    bills. _<< YES >>_
    Cogent, out of the goodness of their hearts, continued to let a
    non-paying customer keep their connectivity up and active, and
    continued to freely import prefixes across BGP neighbors from
    this non-paying defunct customer. _<< YES, and in the mean time,
    someone broke into that router and changed the password, so I
    couldn't remotely shut down BGP  >>_
    Now, someone else has gained access to this non-paying, defunct
    customer's router (which Cogent is still providing free
    connectivity to, out of the goodness of their hearts), and is
    generating RPKI-valid announcements from it, which have somehow
    not caused a flurry of messages on the outages list about prefix
    hijackings. _<<SORT OF, By ARIN registration, neither the AS nor
    the prefixs coming from that router were valid because they
    found their way into possession by other parties.  >>_

    The elements to your claim don't really seem to add up.
    1) ISPs aren't famous for letting non-bill-paying customers stay
    connected for very long past the grace period on their billing
    cycle, let alone long after the company has gone belly-up. _<< I
    disagree >>_
    2) It's not impossible to generate RPKI-valid announcements from
    a hijacked network, but it's very difficult to generate *bogus*
    RPKI-valid announcements from a compromised router--that's the
    whole point of RPKI, to be able to validate that the prefixes
    being announced from an origin are indeed the ones that are
    owned by that origin. _<< They were valid at one time.  They no
    longer are.  I'm not sure when each prefix or the AS were
    transfered to the new owners by ARIN >>__
    _
    __

    Can you provide specific prefix and AS_PATH combinations being
    originated by that router that are "bogus" and don't belong to
    the router's ASN? _<< I don't see that AS in a public route
    server any more.  This is resolved.  I should have taken a
    screen shot, but I didn't.  Look for 216.197.80.0/20 >>_

    If, however, what you meant is that the router used to be ASN
    XXXXX, and is now suddenly showing up as ASN 36471 _<< NO, it
    was always AS36471, but that AS is no longer owned by S2NL >>_,
    and Cogent happily changed their BGP neighbor statements to
    match the new ASN _<< NO >>_, even though the entity no longer
    exists and hasn't been paying their bills for some time, then
    that would imply a level of complicity on Cogent's part that
    would make them unlikely to respond to your abuse reports.  That
    would be a very strong allegation to make, and the necessary
    level of documented proof of that level of malfeasance would be
    substantial. _<< Neither Cogent nor S2NL were practicing
    malevalence.  S2NL was practicing incompetence.  AS number was
    transfered to a new entity by ARIN.  Nobody home at S2NL to turn
    down the router.  Cogent wouldn't act on my requests because I
    was taken off the list.  New AS owner asked me to help.  I'm not
    too busy these days, so I obliged.  Had no other option other
    than posting to NANOG, and it worked.  Cogent shut down the
    compromised router and bogus advertisements vanished from the
    public routing table. >> _

    In short--I'm having a hard time understanding how a non-paying
    entity still has working connectivity and BGP sessions, which
    makes me suspect there's a different side to this story we're
    not hearing yet.  ^_^;

    Thanks!

    Matt





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