AWS Xms 2.5 - 'importer.php?what' Directory Traversal

Advisory ID: HTB23147
Product: AWS XMS
Vendor: http://www.aws-dms.com
Vulnerable Version(s): 2.5 and probably prior
Tested Version: 2.5
Vendor Notification: March 6, 2013 
Vendor Patch: March 16, 2013 
Public Disclosure: March 27, 2013 
Vulnerability Type: Path Traversal [CWE-22]
CVE Reference: CVE-2013-2474
Risk Level: Medium 
CVSSv2 Base Score: 5 (AV:N/AC:L/Au:N/C:P/I:N/A:N)
Solution Status: Fixed by Vendor
Discovered and Provided: High-Tech Bridge Security Research Lab ( https://www.htbridge.com/advisory/ ) 

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Advisory Details:

High-Tech Bridge Security Research Lab discovered path traversal vulnerability in AWS XMS, which can be exploited to read contents of arbitrary files.


1) Path Traversal in AWS XMS: CVE-2013-2474

The vulnerability exists due to insufficient filtration of "what" HTTP GET parameter passed to "/importer.php" script before using it in PHP "file()" function. A remote attacker can read contents of arbitrary files on the target system.

The vulnerable script sets "text/javascript" Content-Type for the output data, which makes exploitation of the vulnerability via a web browser inconvenient. Exploitation via telnet or wget utilities is easier. 

The following PoC (Proof of Concept) code uses wget utility to download source code of "/default.php" file, which contains application configuration data and administrator’s credentials:


wget http://[host]/importer.php?what=defaults.php%00.js


To bypass protections against NULL-byte injection (implemented in PHP 5.3.4 and later versions) or enabled "magic_quotes_gpc", alternative techniques based on path normalization and length restrictions can be used.

The second PoC code uses a large amount of '/' symbols (4096 is sufficient for the majority of platforms) to bypass the restrictions and get source code of the "/default.php" file:


wget http://[host]/importer.php?what=defaults.php///////...//////.js


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Solution:

Upgrade to AWS XMS 2.6

More Information:
http://www.aws-dms.com/temp.php?use=templates/download.xml#xms-2.6

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References:

[1] High-Tech Bridge Advisory HTB23147 - https://www.htbridge.com/advisory/HTB23147 - Path Traversal in AWS XMS.
[2] AWS XMS - http://www.aws-dms.com/ - XMS is an online visual web development enviroment and framework, providing a web application base, with multi language support, based on XML.
[3] Common Vulnerabilities and Exposures (CVE) - http://cve.mitre.org/ - international in scope and free for public use, CVE® is a dictionary of publicly known information security vulnerabilities and exposures.
[4] Common Weakness Enumeration (CWE) - http://cwe.mitre.org - targeted to developers and security practitioners, CWE is a formal list of software weakness types. 

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Disclaimer: The information provided in this Advisory is provided "as is" and without any warranty of any kind. Details of this Advisory may be updated in order to provide as accurate information as possible. The latest version of the Advisory is available on web page [1] in the References.