Below are the .htaccess IP blacklisting codes I mentioned in 3 Ways To Spam Proof, Hack Proof WordPress Blogs & Ecommerce Sites. Simply copy & paste it to the bottom of your .htaccess file. You can find the .htaccess file in the main directory where you installed WordPress.
############################################################## ## block blacklisted IPs deny from 79.171.34.24 deny from 64.13.232.232 deny from 104.254.244.128 deny from 88.198.65.46 deny from 78.46.158.231 deny from 184.154.38.45 deny from 217.23.7.144 deny from 178.33.232.230 deny from 144.76.189.18 deny from 198.11.132.241 deny from 104.254.244.128 deny from 104.20.23.42 deny from 89.111.166.60 deny from 5.45.68.94 deny from 192.64.147.216 deny from 217.23.7.180 deny from 93.190.142.201 deny from 78.110.60.230 deny from 8.21.4.254 deny from 67.217.35.30 deny from 62.219.8.231 deny from 74.52.245.146 deny from 69.64.58.188 deny from 188.165.230.147 deny from 88.190.40.44 deny from 88.198.53.144 deny from 38.100.21.67 deny from 96.227.124.38 deny from 67.221.59.144 deny from 209.58.82.142 deny from 176.9.111.204 deny from 66.249.16.212 deny from 198.186.192.44 deny from 174.127.132.10 deny from 38.229.70.44 deny from 50.112.107.16 deny from 222.79.5.211 deny from 38.100.21.62 deny from 184.106.154.60 deny from 178.32.77.80 deny from 96.227.124.37 deny from 54.241.94.207 deny from 91.207.6.18 deny from 198.27.74.13 deny from 5.135.125.181 deny from 69.64.32.217 deny from 72.233.96.146 deny from 38.100.21.63 deny from 109.163.230.228 deny from 89.184.76.120 deny from 85.13.147.92 deny from 108.171.255.43 deny from 108.171.255.42 deny from 108.171.255.66 deny from 108.171.255.67 deny from 108.171.255.68 deny from 83.236.196.154 deny from 89.205.118.76 deny from 202.131.107.130 deny from 120.72.92.242 deny from 120.28.127.78 deny from 178.125.45.163 deny from 136.169.145.107 deny from 202.77.107.107 deny from 49.159.169.40 deny from 123.205.17.32 deny from 123.231.224.5 deny from 60.174.67.157 deny from 61.172.115.211 deny from 101.68.158.90 deny from 134.17.31.249 deny from 122.173.229.151 deny from 85.110.239.20 deny from 109.188.127.162 deny from 92.84.84.192 deny from 109.188.127.162 ########################
Enjoy you newly found peace of mind!