Re: Reviewing security parameters

[exon <exon () home se>]

Simon Lemieux wrote:
> Hi there,
>   I just composed a login page for my administration of my website.
>
> I just wanted to make sure I had taken everything in consideration when 
> programming that php script.  My main focus is, of course, security.
>
> At first a login variable is initialized with "guest" in it.  If the 
> whole script fails or if the user was not granted access, it will return 
> "guest".  It is then the duty of the index.php (that called my login 
> script) to check what login was returned and take action if it was 
> "guest", like refusing all access.  But as you see the script is also 
> designed to let a guest come in and still use some things.
>
> Guest access is denied on my administration page of course.
>
> The script checks if it was run using SSL.  If not it will automatically 
> return the "guest" user and will print a link to the same page with 
> https://...  So it always authenticate users with SSL.
>
> Also, the inputs the user will send to login are the forms _REQUESTs 
> that contains login and password and then the input become a COOKIE 
> which contains a random ID.  All these inputs are checked to see if they 
> are trustable; they must contain only letters and numbers, I've also 
> allowed some punctuation but no " or '...
>
> The Cookie ID is a string of 32 characters given randomly and stored in 
> a login database with the user's IP address and user ID.
>
> So I check to see if both ID and IP matches the user's.
>
> At any point if the Cookie contains wrong information or if it contains 
> untrustable characters, the user is disconnected (ie. all login records 
> are closed and user will have to re-auth).
>
> Logins, disconnection, bad login/passwords, untrustable characters are 
> reported in a Log database.
>
> Do you guys think this script is safe?
If you post it I might be able to tell you. If you don't, then there's 
no way of telling if the script is safe or not. It sounds like you're 
thinking in a good direction, but until I see the code I can't really be 
of more help than that.

> Thanks,
>   Simon
You're welcome.


/Andreas