This /28 is sending spam for a publisher of «peer-reviewed open access journals» advertised by spam sent to scraped or appended email addresses. The same spammer is present in 15.235.16.128/26, which is also listed in the SBL.
SENDING IPs:
15.235.16.208 pmc.k.theopenjournals.com
15.235.16.209 pmc.l.theopenjournals.com
15.235.16.210 pmc.m.theopenjournals.com
15.235.16.211 pmc.n.theopenjournals.com
15.235.16.212 pmc.o.theopenjournals.com
15.235.16.213 pmc.p.theopenjournals.com
15.235.16.214 pmc.q.theopenjournals.com
15.235.16.215 pmc.r.theopenjournals.com
15.235.16.216 pmc.s.theopenjournals.com
15.235.16.217 pmc.t.theopenjournals.com
15.235.16.218 pmc.u.theopenjournals.com
15.235.16.219 pmc.v.theopenjournals.com
15.235.16.220 pmc.w.theopenjournals.com
15.235.16.221 pmc.x.theopenjournals.com
15.235.16.222 pmc.y.theopenjournals.com
15.235.16.223 pmc.z.theopenjournals.com
SPAM SAMPLE:
Received: from pmc.#.theopenjournals.com (pmc.#.theopenjournals.com [15.235.16.2##])
Date: Wed, 3 Nov 2021 17:##:## +0530
From: «Journal of Cardiovascular Medicine and Cardiology» <editor.jcmc@medoajournal.com>
Subject: Author Notification to <redacted>
<snip>
We hope you are safe and sound. Journal of Cardiovascular Medicine and
Cardiology (ISSN: 2455-2976) is a Peer-Reviewed Open Access journal
<snip>
Richard Kones, Editor-in-Chief
Michael J, Managing Editor
10880 Wilshire Blvd., Suite 1101
Los Angeles, California
90024, USA
<snip>
If you are not comfortable with our emails, please
<http://139.59.60.93/?<x>unsubscribe
<snip>
WHOIS:
VH Hosting, Inc. HO-2 (NET-15-235-0-0-1) 15.235.0.0 — 15.235.255.255
HSPC OVH-CUST-26718749 (NET-15-235-16-208-1) 15.235.16.208 — 15.235.16.223
NetRange: 15.235.16.208 — 15.235.16.223
CIDR: 15.235.16.208/28
NetName: OVH-CUST-26718749
NetHandle: NET-15-235-16-208-1
Parent: HO-2 (NET-15-235-0-0-1)
NetType: Reassigned
OriginAS: AS16276
Customer: HSPC (C08052320)
RegDate: 2021-10-01
Updated: 2021-10-01
Ref: https://rdap.arin.net/registry/ip/15.235.16.208
CustName: HSPC
Address: East Windsor CT 06088-9767
City: East Windsor
StateProv: CT
PostalCode: 06088
Country: US
RegDate: 2021-10-01
Updated: 2021-10-01
Ref: https://rdap.arin.net/registry/entity/C08052320
OrgTechHandle: NOC11876-ARIN
OrgTechName: NOC
OrgTechPhone: +1-855-684-5463
OrgTechEmail: noc@ovh.net
OrgTechRef: https://rdap.arin.net/registry/entity/NOC11876-ARIN
OrgAbuseHandle: ABUSE3956-ARIN
OrgAbuseName: Abuse
OrgAbusePhone: +1-855-684-5463
OrgAbuseEmail: abuse@ovh.ca
OrgAbuseRef: https://rdap.arin.net/registry/entity/ABUSE3956-ARIN
Domain Name: theopenjournals.com
Registry Domain ID: 2616688875_DOMAIN_COM-VRSN
Registrar WHOIS Server: whois.godaddy.com
Registrar URL: http://www.godaddy.com
Updated Date: 2021-06-02T09:19:33Z
Creation Date: 2021-06-02T04:19:35Z
Registrar Registration Expiration Date: 2022-06-02T04:19:35Z
Registrar: GoDaddy.com, LLC
Registrar IANA ID: 146
Registrar Abuse Contact Email: abuse@godaddy.com
Registrar Abuse Contact Phone: +1.4806242505
Domain Status: clientTransferProhibited https://icann.org/epp#clientTransferProhibited
Domain Status: clientUpdateProhibited https://icann.org/epp#clientUpdateProhibited
Domain Status: clientRenewProhibited https://icann.org/epp#clientRenewProhibited
Domain Status: clientDeleteProhibited https://icann.org/epp#clientDeleteProhibited
Registrant Organization: Peertechz Publications Pvt Ltd
Registrant State/Province: Telangana
Registrant Country: IN
Registrant Email: Select Contact Domain Holder link at https://www.godaddy.com/whois/results.aspx?domain=theopenjournals.com
Tech Email: Select Contact Domain Holder link at https://www.godaddy.com/whois/results.aspx?domain=theopenjournals.com
Admin Email: Select Contact Domain Holder link at https://www.godaddy.com/whois/results.aspx?domain=theopenjournals.com
Name Server: NS37.DOMAINCONTROL.COM
Name Server: NS38.DOMAINCONTROL.COM
DNSSEC: unsigned