I am trying to use php to allow my users to change their password through my website. They can change it in my database but not on the secure directory that the website files are stored in. The host server has disabled exec(), system(), and passthru() "for security reasons". Is there some other way I can send a passwd command to the shell so that when a user changes his password it is changed both in the database and on the server?

If it's disabled for security reasons and you want to force it, then doesn't that constitute deliberately weakening security? How about indirect changes? Say you include a database field "has_changed" which serves as a flag that gets set when a user changes his pass. You add a non-root background process that at intervals queries the database for the "has_changed" flag, logs what its doing, extracts the username and pass to a temp file if the username is validated and known and resets the field. Then add a more privileged process that logs what its doing, reads the temp file, checks the username, validates the pass for the usual suspects, backups the old pass and then changes it. Now PHP makes crappy programming easy to do so this relies on a) nobody coming up with a qualitatively safer alternative, b) good security posture of the box and c) you being a responsable PHP programmer who *knows* and acts on A Guide to Building Secure Web Applications.

Great idea! I'll have to check on how privileged a process I can run. Also, being a newbie to php (I just picked it up from a book) I've never heard of A Guide to Building Secure Web Applications. But I'll check it out. Thanks!