---------------------------------------------------------------------- IRM Security Advisory No. 015 File system path disclosure on TYPO3 Web Content Manager Vulnerablity Type / Importance: Information Leakage / Medium Problem discovered: January 13th 2006 Vendor contacted: January 13th 2006 Advisory published: January 19th 2006 ---------------------------------------------------------------------- Abstract: TYPO3 is a free Open Source content management system for enterprise purposes on the web and in intranets. It offers full flexibility and extendability while featuring an accomplished set of ready-made interfaces, functions and modules. Description: IRM has discovered an information leakage vulnerability in TYPO3 that allows remote users to disclose the file system path of the application when requesting certain files. The following files were found to disclose the application path: http://hostname/typo3/t3lib/thumbs.php http://hostname/tslib/showpic.php http://hostname/t3lib/stddb/tables.php Technical details: The issue is due to the application failing to properly determine its own physical path and therefore trying to 'require()' a wrong class file. From init.php, line 71: define('PATH_thisScript',str_replace('//','/', str_replace('\\','/', (php_sapi_name()=='cgi'||php_sapi_name()=='isapi' ||php_sapi_name()=='cgi-fcgi')&&($_SERVER['ORIG_PATH_TRANSLATED']?$_SERVER[' ORIG_PATH_TRANSLATED']:$_SERVER['PATH_TRANSLATED'])? ($_SERVER['ORIG_PATH_TRANSLATED']?$_SERVER['ORIG_PATH_TRANSLATED']:$_SERVER[ 'PATH_TRANSLATED']):($_SERVER['ORIG_SCRIPT_FILENAME']?$_SERVER['ORIG_SCRIPT_ FILENAME']:$_SERVER['SCRIPT_FILENAME'])))); From the PHP manual: "You can define a constant by using the define()-function. Once a constant is defined, it can never be changed or undefined" The vulnerable files listed above fail to include init.php and the 'PATH_thisScript' variable is locally calculated: define('PATH_thisScript',str_replace('//','/', str_replace('\\','/', (php_sapi_name()=='cgi'||php_sapi_name()=='isapi' ||php_sapi_name()=='cgi-fcgi')&&($_SERVER['ORIG_PATH_TRANSLATED']?$_SERVER[' ORIG_PATH_TRANSLATED']:$_SERVER['PATH_TRANSLATED'])? ($_SERVER['ORIG_PATH_TRANSLATED']?$_SERVER['ORIG_PATH_TRANSLATED']:$_SERVER[ 'PATH_TRANSLATED']):($_SERVER['ORIG_SCRIPT_FILENAME']?$_SERVER['ORIG_SCRIPT_ FILENAME']:$_SERVER['SCRIPT_FILENAME'])))); define('PATH_site', ereg_replace('[^/]*.[^/]*$','',PATH_thisScript)); define('PATH_t3lib', PATH_site.'t3lib/'); define('PATH_tslib', PATH_site.'tslib/'); At this point, constants 'PATH_t3lib' and 'PATH_tslib' contain wrong values and any 'require()' function using these constants will not work and will disclose the file system path. Tested Versions: Version 3.7.1 Vendor & Patch Information: Contact was initially made via the TYPO3 bug reporting system on January 13th 2006. On January 14th a patch for the issue was published on the site (http://bugs.typo3.org/view.php?id=2248) Workarounds: IRM are not aware of any workarounds for this issue. Credits: Research & Advisory: Rodrigo Marcos Disclaimer: All information in this advisory is provided on an 'as is' basis in the hope that it will be useful. Information Risk Management Plc is not responsible for any risks or occurrences caused by the application of this information. A copy of this advisory may be found at: http://www.irmplc.com/advisories.htm ---------------------------------------------------------------------- Information Risk Management Plc. Kings Building, Smith Square, London, United Kingdom SW1P 3JJ +44 (0)207 808 6420
