ddos

For smaller scale DDoS attacks, Web Application Firewall (WAF) like Mod Security and Mod Evasive will mitigate DDoS attacks. For larger scale DDoS attacks, you may need to turn to professional DDoS mitigation service provider.

1. Install Mod Security Apache Module.

Apache is the most popular web server being used today. Apache Killer exploit which was released in August 2011, exploits a vulnerability in the Apache software by sending a crafted "Range" HTTP header. Apache Killer attack abuses the HTTP protocol by requesting URL content to be returned in a huge number of small chunks, which leads to hundreds of large memory fetches causing a server to run out of memory and crash. This vulnerability identified as CVE-2011-3192 was fixed in httpd-2.2.21.