La commande pour avoir les IP :

zgrep "elrekt.php" /var/log/apache2/error* | awk '{print $10}' | sed 's/:/ /g' | awk '{print $1}' | sort  | uniq -c
      1 112.126.90.41
      1 116.147.2.110
      1 122.14.209.13
      1 158.69.13.199
      1 193.112.88.67
      1 210.21.218.26
      1 223.75.249.2
      1 27.50.160.35
      1 49.233.63.234
      1 91.242.37.16

Ensuite un petit blocage :

iptables -A INPUT -s 112.126.90.41 -j DROP
-> China Hangzhou Aliyun Computing Co. Ltd 
iptables -A INPUT -s 116.147.2.110 -j DROP
->  China Nanjing China Unicom 
iptables -A INPUT -s 122.14.209.13 -j DROP
-> China Beijing Beijing Teamsun Technology Co.ltd. 
iptables -A INPUT -s 158.69.13.199 -j DROP
-> Canada Montreal Portalpbx Eirl 
iptables -A INPUT -s 193.112.88.67 -j DROP
-> China Beijing Tencent Cloud Computing (beijing) Co. Ltd 
iptables -A INPUT -s 210.21.218.26 -j DROP
-> China Shenzhen Shenzhen Branch China Netcom Corp 
iptables -A INPUT -s 223.75.249.2 -j DROP
-> China Xiangyang China Mobile Communications Corporation 
iptables -A INPUT -s 27.50.160.35 -j DRO
-> China Zhengzhou Henan Xinfeijinxin Computer Co. Ltd 
iptables -A INPUT -s  49.233.63.234  -j DROP
-> China Beijing Tencent Cloud Computing (beijing) Co. Ltd. 
iptables -A INPUT -s 91.242.37.16  -j DROP
-> RUSSIAN FEDERATION