ICMP timestamp请求响应漏洞CVE-1999-0524解决方法

1、添加进和出的规则

firewall-cmd --permanent --direct --add-rule ipv4 filter INPUT 0 -p ICMP --icmp-type timestamp-request -m comment --comment "deny ICMP timestamp" -j DROP
firewall-cmd --permanent --direct --add-rule ipv4 filter OUTPUT 0 -p ICMP --icmp-type timestamp-request -m comment --comment "deny ICMP timestamp" -j DROP
firewall-cmd --permanent --direct --add-rule ipv4 filter INPUT 0 -p ICMP --icmp-type timestamp-reply -m comment --comment "deny ICMP timestamp" -j DROP
firewall-cmd --permanent --direct --add-rule ipv4 filter OUTPUT 0 -p ICMP --icmp-type timestamp-reply -m comment --comment "deny ICMP timestamp" -j DROP

以上包括了进和出的规则

只是封进的规则可以只填两条

firewall-cmd --permanent --direct --add-rule ipv4 filter INPUT 0 -p ICMP --icmp-type timestamp-request -m comment --comment "deny ICMP timestamp" -j DROP
firewall-cmd --permanent --direct --add-rule ipv4 filter INPUT 0 -p ICMP --icmp-type timestamp-reply -m comment --comment "deny ICMP timestamp" -j DROP

防火墙重启载入规则

firewall-cmd --reload

查看添加规则

firewall-cmd --direct --get-all-rules

如果看不到规则，则重启防火墙systemctl restart firewalld