country: ZZ (in Whois of IP) ? Where / what is ZZ?

We have problems with spammer, attacker from these IPs. And there is no contact, no abuse-email etc. 

Problem:

whois 121.127.34.155
% [whois.apnic.net]
% Whois data copyright terms    http://www.apnic.net/db/dbcopyright.html

% Information related to '121.127.34.0 - 121.127.34.255'

% Abuse contact for '121.127.34.0 - 121.127.34.255' is 'no-email@apnic.net'

inetnum:        121.127.34.0 - 121.127.34.255
netname:        STUB-121-127-34SLASH24
descr:          Transferred to the ARIN region on 2024-07-03T10:51:43Z.
country:        ZZ
admin-c:        STUB-AP
tech-c:         STUB-AP
abuse-c:        AS2444-AP
status:         ALLOCATED PORTABLE
mnt-by:         APNIC-STUB
mnt-irt:        IRT-STUB-AP
last-modified:  2024-07-03T01:02:09Z
source:         APNIC

irt:            IRT-STUB-AP
address:        N/A
e-mail:         no-email@apnic.net
abuse-mailbox:  no-email@apnic.net
admin-c:        STUB-AP
tech-c:         STUB-AP
remarks:        IRT for stub records.
remarks:        We do not operate the referring network and
remarks:        are unable to investigate complaints of network abuse.
remarks:        For information about IRT, see www.apnic.net/irt
auth:           # Filtered
mnt-by:         APNIC-HM
last-modified:  2025-11-18T00:33:17Z
source:         APNIC

role:           ABUSE STUBAP
address:        N/A
country:        ZZ
phone:          +000000000
e-mail:         no-email@apnic.net
admin-c:        STUB-AP
tech-c:         STUB-AP
nic-hdl:        AS2444-AP
remarks:        Generated from irt object IRT-STUB-AP
abuse-mailbox:  no-email@apnic.net
mnt-by:         APNIC-ABUSE
last-modified:  2024-01-24T04:05:14Z
source:         APNIC

person:         STUB PERSON
address:        N/A
country:        ZZ
phone:          +00 0000 0000
e-mail:         no-email@apnic.net
nic-hdl:        STUB-AP
remarks:        No contact information for stub records.
mnt-by:         APNIC-HM
last-modified:  2019-09-23T04:53:33Z
source:         APNIC

% This query was served by the APNIC Whois Service version 1.88.34 (WHOIS-UK2)

Solution?