In response to feedback from operational security communities, CAIDA's source address validation measurement project (https://spoofer.caida.org) is automatically generating monthly reports of ASes originating prefixes in BGP for systems from which we received packets with a spoofed source address. We are publishing these reports to network and security operations lists in order to ensure this information reaches operational contacts in these ASes. This report summarises tests conducted within usa, can. Inferred improvements during May 2020: ASN Name Fixed-By 14860 AS-SMARTCOM 2020-05-17 Further information for the inferred remediation is available at: https://spoofer.caida.org/remedy.php Source Address Validation issues inferred during May 2020: ASN Name First-Spoofed Last-Spoofed 54825 PACKET 2016-04-15 2020-05-01 209 CENTURYLINK-US-LEGACY-QWEST 2016-08-16 2020-05-28 6128 CABLE-NET-1 2016-09-03 2020-05-27 7459 GRANDECOM-AS1 2016-09-26 2020-05-24 20412 CLARITY-TELECOM 2016-09-30 2020-05-25 6181 FUSE-NET 2016-10-10 2020-05-29 11427 TWC-11427-TEXAS 2016-10-21 2020-05-24 174 COGENT-174 2016-10-21 2020-05-29 32440 LONI 2016-11-03 2020-05-31 12083 WOW-INTERNET 2016-11-09 2020-05-30 39939 RISE-CO-AS39939 2016-11-11 2020-05-30 30036 MEDIACOM-ENTERPRISE-BUSINESS 2016-11-16 2020-05-28 9009 M247 2017-01-10 2020-05-27 63296 AWBROADBAND 2017-09-01 2020-05-27 36236 NETACTUATE 2018-01-13 2020-05-24 40244 TURNKEY-INTERNET 2018-01-14 2020-05-24 12222 AKAMAI 2018-02-14 2020-05-07 20448 VPNTRANET-LLC 2018-09-20 2020-05-20 8047 GCI 2019-04-11 2020-05-28 6428 CDM 2019-06-04 2020-05-16 46300 HSC-WAP 2019-10-30 2020-05-28 21859 ZNET 2019-12-26 2020-05-27 239 UTORONTO 2020-01-28 2020-05-30 13614 ALLWEST 2020-03-16 2020-05-21 26335 MTSU 2020-03-20 2020-05-07 7859 PAIR-NETWORKS 2020-04-03 2020-05-29 5078 ONENET-AS-1 2020-04-06 2020-05-30 13781 ENERGYNET 2020-04-15 2020-05-12 208217 YUNJIANET 2020-04-27 2020-05-25 64236 UNREAL-SERVERS 2020-05-06 2020-05-06 393713 ALL-POINTS-BROADBAND-5 2020-05-08 2020-05-08 53356 WESTCONNECT 2020-05-19 2020-05-19 29844 SENAWAVE 2020-05-22 2020-05-26 18450 WEBNX 2020-05-24 2020-05-24 11650 PLDI 2020-05-25 2020-05-25 6391 URBAN-15 2020-05-29 2020-05-29 Further information for these tests where we received spoofed packets is available at: https://spoofer.caida.org/recent_tests.php?country_include=usa,can&no_block=1 Please send any feedback or suggestions to spoofer-info@caida.org