Dear all:
Until I read the article "PHP Session security" (http://www.webkreator.com/php/configuration/php-session-security.html) I haven't noticed how insecure PHP Sessions are. Basically there're 2 problems: *) It's possible to hijack a session if you know the SID (session id) 1) If you're on a shared server (cheap webhosting) other users can get the SIDs by doing "ls /tmp/sess_*" (/tmp/ is defined on session.save_path on the config file, so it may be different). 2) When a user clicks on an external link, the browser sends the REFERER url and sometimes it contains the SID (if session.use_trans_sid is enabled) PHP offers a security measure: with session.referer_check it will reject SIDs comming from other referers, but the referer url can be easily forged. *) Users can read session data from the session files, which are owned by the server process (every user which has an account on the webserver can read server owned files) (If you're intrested in the subject I would recommend to read full the article: http://www.webkreator.com/php/configuration/php-session-security.html) I have developed some functions to avoid this problems. They replace the standard session functions (using session_set_save_handler), so you only have to include the file at the beggining of your script and (afaik) you're safe :) This is the idea: Apart from the session cookie, I set another one (with the same name and the string '_sec' appended). On this cookie I set a random KEY. The name of the file which contains the session data is the md5 hash of the SID and the KEY together. This turns impossible to guess the session id by looking at the filenames. To hide the data inside the file, the serialized string is crypted using the KEY as password, so nobody can see the content of your user's sessions. You can find the code here: http://www.n3rds.com.ar/files/docs/php_sessions/sess_handler.txt Im looking for suggestions to make it 100% compatible with the standard session functions, and I would like to hear some thougts about the idea Martin Sarsale [EMAIL PROTECTED] __________________________________________________ Do You Yahoo!? Yahoo! Finance - Get real-time stock quotes http://finance.yahoo.com -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
