Fail2Ban: what is apache-overflows?

Question

I am trying to configure fail2ban for my server and have come across: apache-overflows in the .config

What does it do/protect against?

Answer 1

The /etc/fail2ban/filters.d/apache-overflows.conf file may help explain it more:

Notes.: Regexp to catch Apache overflow attempts.

The regex that is being a applied to the log can provide more detail:

failregex = [[]client []] (Invalid method in request|request failed: URI too long|erroneous characters after protocol string)

Certain types of attacks against Apache are done to try and overflow the memory buffer and cause it to crash, effectively creating a denial of service. This filter attempts to detect the attack before it completely overwhelms the web server and then will apply whatever action you specify.