sugarcrm-disclose.txt

`========================================================================  
= SugarCRM Community Edition Local File Disclosure Vulnerability  
=  
= Vendor Website:   
= http://www.sugarcrm.com  
=  
= Affected Version:  
= -- SugarCRM Community Edition 4.5.1   
= -- SugarCRM Community Edition 5.0.0  
=  
= Public disclosure on 29th April 2008  
=  
========================================================================  
Available online at:  
http://www.security-assessment.com/files/advisories/2008-04-29_SugarCRM_  
local_file_disclosure.pdf  
  
== Overview ==  
SugarCRM Community Edition is vulnerable to local file contents   
disclosure.  
This vulnerability can be exploited by a malicious user to disclose  
potentially sensitive information. The flaw is caused due to a lack of   
input filtering in the SugarCRM RSS module, which can be exploited   
to disclose the content of local files.  
  
The RSS module allows SugarCRM users to add RSS feeds to their personal   
RSS list. The application expects an URL value pointing to a valid RSS   
feed.   
However, the URL variable value is not properly sanitised and any URI   
value can be entered instead. In this particular case, it was discovered  
that it is possible to enter a file path to any files on the local  
system hosting the SugarCRM application.  
  
As a result SugarCRM does not display the new RSS feed in the list as it  
is not a valid RSS URL Feed. However, the application creates a local   
file with the filename of the md5 hash of the URL entered. The file is   
created in the directory cache/feeds . If the Apache web server is used,   
the file is created with the user www-data containing read permission.   
  
  
== Exploitation ==  
  
An exploitation example in a LAMP (Linux, Apache, Mysql, PHP)   
environment:  
  
If an authenticated attacker enters a value of “/etc/passwd”   
(without quotes) in the RSS URL field, the application will generate a   
MD5 hash of the string containing the file path. In this case,  
the value “/etc/passwd” is hashed to “c5068b7c2b1707f8939b283a2758a691  
” (without quotes). The MD5 hash is then used as a filename with the   
file contents of /etc/passwd. The file /etc/passwd can then be viewable   
publicly at http://sugarwebsiteaddress/cache/feeds/c5068b7c2b1707f8939b2  
83a2758a691 .  
  
Exploitation of this flaw does not require authentication.  
  
The URL variable is handled by the /modules/Feeds/Feed.php page.   
The array variable $url is passed without filtering to the   
xml_domit_rss_document function at the following line:  
  
$rssdoc = new xml_domit_rss_document ($this->url, ‘cache/feeds/’, 3600);  
  
The XML domit RSS plugin is then called and retrieves the file content   
at the path given and then generate the MD5 hashed file in the   
cache/feeds folder as instructed by the function in Feed.php .  
  
  
== Solutions ==  
  
Install the vendor supplied patches.  
Patch 4.5.1j: http://www.sugarcrm.com/forums/showthread.php?t=31688  
Patch 5.0.0c: http://www.sugarcrm.com/forums/showthread.php?t=32252  
  
== Credit ==  
  
Discovered and advised to SugarCRM  
April 2008 by Roberto Suggi Liverani Craig of Security-Assessment.com  
  
== Greetings ==  
  
To all my SA colleagues and thanks to the great atmosphere in   
Hack in the Bush!  
It was inspirational...  
  
  
== About Security-Assessment.com ==  
  
Security-Assessment.com is Australasia's leading team of Information   
Security consultants specialising in providing high quality Information   
Security services to clients throughout the Asia Pacific region. Our   
clients include some of the largest globally recognised companies in   
areas such as finance, telecommunications, broadcasting, legal and   
government. Our aim is to provide the very best independent advice and   
a high level of technical expertise while creating long and lasting   
professional relationships with our clients.  
  
Security-Assessment.com is committed to security research and   
development, and its team continues to identify and responsibly publish   
vulnerabilities in public and private software vendor's products.   
Members of the Security-Assessment.com R&D team are globally recognised   
through their release of whitepapers and presentations related to new   
security research.  
  
Roberto Suggi Liverani  
Security-Assessment.com  
`