Path Traversal in AWS XMS

2013-03-06T00:00:00
ID HTB23147
Type htbridge
Reporter High-Tech Bridge
Modified 2013-03-19T00:00:00

Description

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