Hi folks,

Recently I read a post regarding the recent incident of Celer Network and noticed a very interesting and successful BGP hijacking towards AS16509.

The attacker AS209243 added AS16509 to their AS-SET and a more specific route object for the /24 where the victim's website is in ALTDB:

(Below is our IRRd4 server NRTM logging, UTC timezone)

irrd.log-20220817.gz:31106270-ADD 96126

irrd.log-20220817.gz:31106280-

irrd.log-20220817.gz:31106281-as-set: AS-SET209243

irrd.log-20220817.gz:31106306-descr: quickhost set

irrd.log-20220817.gz:31106332-members: AS209243, AS16509

irrd.log-20220817.gz:31106362:mnt-by: MAINT-QUICKHOSTUK

irrd.log-20220817.gz:31106392-changed: crussell@quickhostuk.net 20220816

irrd.log-20220817.gz:31106438-source: ALTDB

irrd.log-20220817.gz:31147549-ADD 96127

irrd.log-20220817.gz:31147559-

irrd.log-20220817.gz:31147560-route: 44.235.216.0/24

irrd.log-20220817.gz:31147588-descr: route

irrd.log-20220817.gz:31147606-origin: AS16509

irrd.log-20220817.gz:31147626:mnt-by: MAINT-QUICKHOSTUK

irrd.log-20220817.gz:31147656-changed: crussell@quickhostuk.net 20220816

irrd.log-20220817.gz:31147702-source: ALTDB

Then they started announcing the prefix ... under another AWS ASN (AS14618)

I guess AS1299 Arelion doesn't check if the origin AS of an announcement is in the customer's AS-SET but it's pretty normal and understandable.

https://stat.ripe.net/widget/bgplay#w.resource=44.235.216.0/24&w.ignoreReannouncements=true&w.starttime=1660694458&w.endtime=1661032798&w.rrcs=0&w.instant=null&w.type=bgp

Type: A > announce Involving: 44.235.216.0/24

Short description: The new route 34854 1299 209243 14618 has been announced

Path: 34854, 1299, 209243, 14618,

Community: 1299:35000,34854:3001

Date and time: 2022-08-17 19:39:50 Collected by: 00-2.56.11.1

Hjacking didn't last too long. AWS started announcing a more specific announcement to prevent hijacking around 3 hours later. Kudos to Amazon's security team :-)

Type: A > announce Involving: 44.235.216.0/24

Short description: The new route 58057 34549 5511 1299 16509 has been announced

Path: 58057, 34549, 5511, 1299, 16509,

Community: 5511:521,5511:666,5511:710,5511:5511,34549:100,34549:5511

Date and time: 2022-08-17 23:08:47 Collected by: 00-194.50.92.251

The attacker cleaned up the IRR objects on 17 Aug and surprisingly no one seems to notice them ...

irrd.log-20220819.gz:26517714-ADD 96196

irrd.log-20220819.gz:26517724-

irrd.log-20220819.gz:26517725:as-set: AS-SET209243

irrd.log-20220819.gz:26517750-descr: quickhost set

irrd.log-20220819.gz:26517776-members: AS209243, AS35437, AS37497

irrd.log-20220819.gz:26517815-mnt-by: MAINT-QUICKHOSTUK

irrd.log-20220819.gz:26517845-changed: crussell@quickhostuk.net 20220817

irrd.log-20220819.gz:26517891-source: ALTDB

irrd.log-20220819.gz:26517910-DEL 96197

irrd.log-20220819.gz:26517920-

irrd.log-20220819.gz:26517921-route: 44.235.216.0/24

irrd.log-20220819.gz:26517949-descr: route

irrd.log-20220819.gz:26517967-origin: AS16509

irrd.log-20220819.gz:26517987-mnt-by: MAINT-QUICKHOSTUK

irrd.log-20220819.gz:26518017-changed: crussell@quickhostuk.net 20220816

irrd.log-20220819.gz:26518063-source: ALTDB

Nowadays hijacking a service by forging AS path is pretty easy and RPKI won't be able to solve this (as it validates origin AS and prefixes only) :-(

Regards,
Siyuan