/var/lib/rkhunter/ is in rkhunter 1.4.2-6+deb9u1.
This file is owned by root:root, with mode 0o755.
..
/var/lib/rkhunter/db/
/var/lib/rkhunter/db/backdoorports.dat
/var/lib/rkhunter/db/i18n/
/var/lib/rkhunter/db/i18n/cn
/var/lib/rkhunter/db/i18n/de
/var/lib/rkhunter/db/i18n/en
/var/lib/rkhunter/db/i18n/tr
/var/lib/rkhunter/db/i18n/tr.utf8
/var/lib/rkhunter/db/i18n/zh
/var/lib/rkhunter/db/i18n/zh.utf8
/var/lib/rkhunter/db/mirrors.dat
/var/lib/rkhunter/db/programs_bad.dat
/var/lib/rkhunter/db/signatures/
/var/lib/rkhunter/db/signatures/RKH_Glubteba.ldb
/var/lib/rkhunter/db/signatures/RKH_dso.ldb
/var/lib/rkhunter/db/signatures/RKH_jynx.ldb
/var/lib/rkhunter/db/signatures/RKH_kbeast.ldb
/var/lib/rkhunter/db/signatures/RKH_libkeyutils.ldb
/var/lib/rkhunter/db/signatures/RKH_libkeyutils1.ldb
/var/lib/rkhunter/db/signatures/RKH_libncom.ldb
/var/lib/rkhunter/db/signatures/RKH_pamunixtrojan.ldb
/var/lib/rkhunter/db/signatures/RKH_shv.ldb
/var/lib/rkhunter/db/signatures/RKH_sniffer.ldb
/var/lib/rkhunter/db/signatures/RKH_sshd.ldb
/var/lib/rkhunter/db/signatures/RKH_turtle.ldb
/var/lib/rkhunter/db/signatures/RKH_xsyslog.ldb
/var/lib/rkhunter/db/suspscan.dat
/var/lib/rkhunter/tmp/