Need to 404 “perl.exe”

Question

I was told the below, from SecurityMetrics that this must be resolved. However, there is no cgi-bin or perl file in that path.

When we perform the following http://www.domain.com/cgi-bin/perl in the URL it pulls a 500 internal server error. Please direct this to a 404 not found alone; otherwise, the vulnerability appears valid.

Perl.exe When we perform the following http://www.domain.com/cgi-bin/perl.exe in the URL it pulls a 500 internal server error. Please direct this to a 404 not found alone; otherwise, the vulnerability appears valid.

They also said:

We do understand that it may not exist but please have your site show that. An internal server error does not prove that the file doesn't exist. A 404 not found does.

How can I do that? I'm using PHP 5.2.9 / Apache 2.2 / Centos 4.8

Answer 1

The easiest way to do this is with a mod_rewrite rule. Check this into your .htaccess

RewriteRule /cgi-bin/perl.exe  - [R=404,L]
RewriteRule /cgi-bin/perl  - [R=404,L]

(technically 404 is not a valid response code for mod_rewrite to be sending out, but it works)

Answer 2

Install modsecurity and add the following rule:

SecRule ARGS perl.exe "phase:1,log,deny,status:404"

Not only will you "comply" with this audit (yeah I know), but you will have a full fledged WAF protecting you against many issues you may have in your application.