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SugarCRM Community Edition Local File Disclosure Vulnerability



SugarCRM Community Edition Local File Disclosure Vulnerability
SugarCRM Community Edition Local File Disclosure Vulnerability



========================================================================
= 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 =93/etc/passwd=94
(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  =93/etc/passwd=94 is hashed to =93c5068b7c2b1707f8939b283a2758a691
=94 (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, =91cache/feeds/=92, 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

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