Re: Microsoft Writing Secure Code

Damhuis Anton wrote:
> I have read the book "Designing Secure Web-based Applications", found it quite informative but also somewhat disappointing.
> 
> I was (at the time) looking for a book that assists with "writing secure code". Thus how code should be written, not the way code interfaces with security components.
> 
> Example:
> What is the best way to display User Details:
> 
> ~~Suedo code Begin ~~
> Option 1:
> If var_userLevel = USER then
>    ... display User info
> else
>   ... Display Admin Info
> end if
> 
> 
> 
> Option 2:
> If var_userLevel = ADMIN then
>    ... display Admin info
> else
>   ... Display User Info Info
> end if
> 
> 
> 
> Option 3:
> If var_userLevel = ADMIN then
>    ... display Admin info
> elseif var_userLevel = USER
>   ... Display User Info Info
> else
>   ... Capture Error
> end if
> 
> ~~Suedo code End~~
> 
> 
> 
> To me it is Option 3. Somewhat more work, but a lot more secure, then Option 1. If for some reason someone else writes the code to get the variable for var_userLevel , and that code is hackable, Option 3 will withstand the attack a lot better then Option 1. Option 2 in this case would also be better then Option 1, as Option 1 would display the Admin info for anybody other then user. Option 2 in this case would revert back to the lower level of access. Thus just structuring the If stament differently in Option 1 and 2, already makes the code more secure.
> 
> Also by logging all the errors in option 3's last "Else" statement one can look for any thing overlooked initially (and capture any unknown hacker attacks -although this is reactively)
> 

Hola Anton,

Another answer is "None of the above."  Based on your example, this is 
an archetypical application for Role-Based Access Control (RBAC).  In 
this case, the application makes distinctions among roles and the 
information that various roles can see and what various roles can do. 
Each role would have its own set of objects and behavio(u)rs that are 
invoked from a CASE statement (as opposed to a bunch of cascading IFs).

Cheers,

/g