Apache2 : Configure mod_evasive2024/05/31

	Enable mod_evasive module to defend from DoS attacks and so on.
[1]	Install and configure mod_evasive.

root@www:~#

apt -y install libapache2-mod-evasive

root@www:~#

vi /etc/apache2/mods-available/evasive.conf

# uncomment each line to configure

<IfModule mod_evasive20.c>
    # hash table size
    DOSHashTableSize    3097
    # threshold for the number of requests for the same page per page interval
    DOSPageCount        2
    # threshold for the total number of requests for any object by the same client on the same listener per site interval
    DOSSiteCount        50
    # the interval for the page count threshold
    DOSPageInterval     1
    # the interval for the site count threshold
    DOSSiteInterval     1
    # amount of time (in seconds) that a client will be blocked for if they are added to the blocking list
    DOSBlockingPeriod   10

    # uncomment and configure follows if you need
    # notification address if IP address becomes blacklisted
    #DOSEmailNotify      root@localhost
    # possible to set any command
    #DOSSystemCommand    "su - someuser -c '/sbin/... %s ...'"
    # log directory
    #DOSLogDir           "/var/log/mod_evasive"
</IfModule>

root@www:~#

mkdir /var/log/mod_evasive

root@www:~#

chown www-data:www-data /var/log/mod_evasive

root@www:~#

systemctl reload apache2

[2]	Test to access to Apache2.

root@www:~#

for ((i=1; i <= 20; i++)); do curl -I localhost; done

HTTP/1.1 200 OK
Date: Fri, 31 May 2024 01:31:07 GMT
Server: Apache/2.4.58 (Ubuntu)
Upgrade: h2,h2c
Connection: Upgrade
Last-Modified: Thu, 30 May 2024 23:46:27 GMT
ETag: "29af-619b479c01d06"
Accept-Ranges: bytes
Content-Length: 10671
Vary: Accept-Encoding
Content-Type: text/html

HTTP/1.1 200 OK
Date: Fri, 31 May 2024 01:31:07 GMT
Server: Apache/2.4.58 (Ubuntu)
Upgrade: h2,h2c
Connection: Upgrade
Last-Modified: Thu, 30 May 2024 23:46:27 GMT
ETag: "29af-619b479c01d06"
Accept-Ranges: bytes
Content-Length: 10671
Vary: Accept-Encoding
Content-Type: text/html

.....
.....

# turn to "403 Forbidden" if blocked
HTTP/1.1 403 Forbidden
Date: Fri, 31 May 2024 01:31:07 GMT
Server: Apache/2.4.58 (Ubuntu)
Content-Type: text/html; charset=iso-8859-1

HTTP/1.1 403 Forbidden
Date: Fri, 31 May 2024 01:31:07 GMT
Server: Apache/2.4.58 (Ubuntu)
Content-Type: text/html; charset=iso-8859-1

.....
.....

# if blocked, logs are recorded

root@www:~#

ll /var/log/mod_evasive

total 16
drwxr-xr-x  2 www-data www-data 4096 May 31 01:35 ./
drwxrwxr-x 13 root     syslog   4096 May 31 01:34 ../
-rw-r--r--  1 www-data www-data    5 May 31 01:35 dos-10.0.0.52
-rw-r--r--  1 www-data www-data    5 May 31 01:35 dos-::1

# if set notification, it is sent like follows

root@www:~#

mail

"/var/mail/root": 3 messages 3 new
>N  1 root@www.srv.worl  Fri May 31 01:30   30/1204  Cron <www-data@www> [ -x /u
 N  2 www-data@www.srv.  Fri May 31 01:35   19/601
 N  3 www-data@www.srv.  Fri May 31 01:35   19/613
& 3
Message 3:
From www-data@www.srv.world  Fri May 31 01:35:54 2024
X-Original-To: root@localhost
To: root@localhost
MIME-Version: 1.0
Content-Type: text/plain; charset="ANSI_X3.4-1968"
Content-Transfer-Encoding: 8bit
Date: Fri, 31 May 2024 01:35:54 +0000 (UTC)
From: www-data <www-data@www.srv.world>

To: root@localhost
Subject: HTTP BLACKLIST 10.0.0.52

mod_evasive HTTP Blacklisted 10.0.0.52

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