A Novel Protective Framework for Defeating HTTP-Based Denial of Service and Distributed Denial of Service Attacks

Algorithm 6

Flash crowd attack entropy algorithm.

calculate avg_h = (hot_uri1_clicks + hot_uri2_clicks + ⋯ + hot_uriN_clicks)/N

IF (avg_h >= 10000)

            calculate entropy H = −H(hot_uri1) + −H(hot_uri2) + ⋯ + −H(hot_uriN)

    IF (H <= −0.5 OR H >= +0.5)

                decrease Timeout

                decrease MaxKeepAliveRequests

                               IF (Timeout == 0 && MaxKeepAliveRequests == 0)

                                              return HTTP_FORBIDDEN

                                              Blacklist_Table(remote_ip)

                                              EdgeRouter_Ban(remote_ip)

                               ENDIF

    ENDIF

ENDIF