I have installed my turnkey website , a photo rating website, since two years or so. We did add features to prevent the average internet users from taking the pics, like stoping the drag&drop, disabling right click, disabling print screen.
The website was working fine until recently, i dont know when or why exactly, the problem is when a new user sign up, the script change their password to something specific. so they are unable to login!

Any ideas on why or how to fix this?

Thank you.

Might be some malcious code is working behind the script, was there any modification to the script recently.

Did you change the server configuration, php settings?

I think Recently u change the server configuration may be u upgrade the server configuration so you need to some chanages server configuration file (php.ini)

I hope no need to change the source code

Interesting!. I think we have to fix this issue in step by step manner.

First when you insert the values of your sign up form , try to print the sql statement. It will give you idea as whats going into database. If you are using MD5 etc etc conferim that its correct as entered by user.

If this is correct check your database is same value is going into table or not. Then we can come to know where the issue is.