Someone tried to hack my root user. It was interesting to me to find all users in my system. I don't remember I create any of them. Can hacker use any of other default users to enter the system (with default Linux system settings)? I can't login with any of them to check because I don't know their passwords.

I run command to get all users: cat /etc/passwd:

root:x:0:0:root:/root:/bin/bash

bin:x:1:1:bin:/bin:/sbin/nologin

daemon:x:2:2:daemon:/sbin:/sbin/nologin

adm:x:3:4:adm:/var/adm:/sbin/nologin

lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin

sync:x:5:0:sync:/sbin:/bin/sync

shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown

halt:x:7:0:halt:/sbin:/sbin/halt

mail:x:8:12:mail:/var/spool/mail:/sbin/nologin

operator:x:11:0:operator:/root:/sbin/nologin

games:x:12:100:games:/usr/games:/sbin/nologin

ftp:x:14:50:FTP User:/var/ftp:/sbin/nologin

nobody:x:65534:65534:Kernel Overflow User:/:/sbin/nologin

dbus:x:81:81:System message bus:/:/sbin/nologin

systemd-coredump:x:999:997:systemd Core Dumper:/:/sbin/nologin

systemd-resolve:x:193:193:systemd Resolver:/:/sbin/nologin

tss:x:59:59:Account used for TPM access:/dev/null:/sbin/nologin

polkitd:x:998:996:User for polkitd:/:/sbin/nologin

unbound:x:997:994:Unbound DNS resolver:/etc/unbound:/sbin/nologin

sssd:x:996:993:User for sssd:/:/sbin/nologin

chrony:x:995:992::/var/lib/chrony:/sbin/nologin

sshd:x:74:74:Privilege-separated SSH:/var/empty/sshd:/sbin/nologin

nginx:x:994:991:Nginx web server:/var/lib/nginx:/sbin/nologin