SugarCRM Community Edition Local File Disclosure Vulnerability

2008.05.01
Credit: Roberto Suggi
Risk: Medium
Local: No
Remote: Yes
CWE: CWE-22


CVSS Base Score: 5/10
Impact Subscore: 2.9/10
Exploitability Subscore: 10/10
Exploit range: Remote
Attack complexity: Low
Authentication: No required
Confidentiality impact: Partial
Integrity impact: None
Availability impact: None

======================================================================== = 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


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