5 ms·

Security needs less implications and more explicit answers. Besides, there is more to business logic than simple (or complex) access control. More than one Fac

by bonaldi 15y ago

Security needs less implications and more explicit answers. Besides, there is more to business logic than simple (or complex) access control. More than one Facebook game has discovered to their cost the problems of trusting the score the client is sending to you. Or take discounts: if I want to give 10% off for orders over £20, where does that rule live? If it's on the client, well, what stops the client changing that to 90% off? Perhaps you ACL the order table and only allow access to a non-client facing instance. The client sends an order to that, which verifies it and sends it on if approved? Well, fine, but that's a server, and one of the main pitches here is "No servers! No server code."

buu700 15y ago
Sure, those are fine examples of use cases that fall outside the general category of applications which don't require server-side data validation. You're using "security" to mean something totally different now (protection of your data from other users v. prevention of you modifying your own data in unexpected ways). My point before was that most applications just don't have that concern of limiting what users can do to their own data, at least for the MVP, because in most applications that will only affect the user herself.
- bonaldi 15y ago
  It all amounts to the same thing: no server means putting your trust in the client. Which you should never do. You don't trust who the client says they are (authentication), you don't trust what the client says they can do (authorisation), you don't trust what they're giving you (validation), It's not something you bolt on later. You have to bake this in from the start, because even the simplest operations depend on it. Posting a comment? Great: are you allowed to post? Who are you posting as? Is there HTML in your post?
  - buu700 15y ago
    You don't trust who the client says they are I shouldn't trust a hashed username and password? How are server-based systems more secure? you don't trust what the client says they can do That's a non-issue if it's handled by ACLs on the server. you don't trust what they're giving you Like I mentioned before, though, for most applications you can trust what they're giving you. Sure, Amazon isn't going to ask the client how much an iPad costs and WoW isn't going to ask the client for the player's stats, but why should an application like Facebook care to verify whether you want to modify your own settings or send a friend request / wall post / whatever? If you attempt to perform an unexpected action (say, post to the wall of someone who's blocked you), the other user's client application logic (which is beyond your control) can still handle the junk data gracefully and simply. Also, later on (when you have more developer time to spare), if you want to for whatever reason, you can easily just deploy a server-side "garbage collector" of sorts to regularly clean up the database without disrupting client-side flow. It's not something you bolt on later. It can be, provided that it's only in the form of new features rather than fixing something which was insecurely implemented to start with. (For example, maybe the MVP is free but the next iteration is freemium and requires server-side price validation.)
    - bonaldi 15y ago
      I shouldn't trust a hashed username and password? How are server-based systems more secure? How are you going to verify the password without a server? Passwords are a server-based system. That's a non-issue if it's handled by ACLs on the server. ACLs fine-grained enough to handle modern security scenarios are going to be just as complex as doing traditional validation. Any non-trivial sites are quickly going to get way more complex than just doing it the old-fashioned way. So why bother? why should an application like Facebook care to verify whether you want to modify your own settings or send a friend request? Because privacy is mission-critical for Facebook, and an exploit that allows me to send a friend request to myself as you is an unmitigated disaster for them. And trivial to do in a mostly-client world. Beyond trivial if I have access to the other client, which I am one browser bug or open wifi access point away from having. It can be, provided that it's only in the form of new features And those new features are going to be written in what? Since your MVP's framework doesn't support server-side logic, you're now splitting your code in three. Now you're either in maintenance or rewrite hell, just as you're taking off. That's not one of the good problems to have, it's one of the stupid problems you should have avoided by laying the right foundations at the start.
      - buu700 15y ago
        How are you going to verify the password without a server? Only a dreadfully insecure system would choose to compare plain text passwords over the standard practice of hashing. It makes no difference if the hash is done client-side or server-side; if anything, even with SSL it's more secure to keep the plain text password removed from the network. ACLs fine-grained enough to handle modern security scenarios are going to be just as complex as doing traditional validation. How so? If I can manage my Facebook privacy settings graphically, any developer can manage ACLs in a DB schema graphically. No reason to unnecessarily clutter up code and deal with pointless architectural issues. Because privacy is mission-critical for Facebook, and an exploit that allows me to send a friend request to myself as you is an unmitigated disaster for them. And trivial to do in a mostly-client world. Beyond trivial if I have access to the other client, which I am one browser bug or open wifi access point away from having. Uh, what? If you have access to someone else's account then the game is already lost; no backend can solve that. Since your MVP's framework doesn't support server-side logic, you're now splitting your code in three. Now you're either in maintenance or rewrite hell, just as you're taking off. ...What? Who says whatever framework I use won't support server-side logic? Even vanilla JavaScript or jQuery is fine for AJAX calls. Not sure where you're getting "rewrite hell" from, but you must really hate the client APIs provided by Google, Yahoo, Facebook, and Microsoft.

by bonaldi 15y ago

buu700 15y ago

Sure, those are fine examples of use cases that fall outside the general category of applications which don't require server-side data validation. You're using "security" to mean something totally different now (protection of your data from other users v. prevention of you modifying your own data in unexpected ways). My point before was that most applications just don't have that concern of limiting what users can do to their own data, at least for the MVP, because in most applications that will only affect the user herself.

bonaldi 15y ago
It all amounts to the same thing: no server means putting your trust in the client. Which you should never do. You don't trust who the client says they are (authentication), you don't trust what the client says they can do (authorisation), you don't trust what they're giving you (validation), It's not something you bolt on later. You have to bake this in from the start, because even the simplest operations depend on it. Posting a comment? Great: are you allowed to post? Who are you posting as? Is there HTML in your post?
- buu700 15y ago
  You don't trust who the client says they are I shouldn't trust a hashed username and password? How are server-based systems more secure? you don't trust what the client says they can do That's a non-issue if it's handled by ACLs on the server. you don't trust what they're giving you Like I mentioned before, though, for most applications you can trust what they're giving you. Sure, Amazon isn't going to ask the client how much an iPad costs and WoW isn't going to ask the client for the player's stats, but why should an application like Facebook care to verify whether you want to modify your own settings or send a friend request / wall post / whatever? If you attempt to perform an unexpected action (say, post to the wall of someone who's blocked you), the other user's client application logic (which is beyond your control) can still handle the junk data gracefully and simply. Also, later on (when you have more developer time to spare), if you want to for whatever reason, you can easily just deploy a server-side "garbage collector" of sorts to regularly clean up the database without disrupting client-side flow. It's not something you bolt on later. It can be, provided that it's only in the form of new features rather than fixing something which was insecurely implemented to start with. (For example, maybe the MVP is free but the next iteration is freemium and requires server-side price validation.)
  - bonaldi 15y ago
    I shouldn't trust a hashed username and password? How are server-based systems more secure? How are you going to verify the password without a server? Passwords are a server-based system. That's a non-issue if it's handled by ACLs on the server. ACLs fine-grained enough to handle modern security scenarios are going to be just as complex as doing traditional validation. Any non-trivial sites are quickly going to get way more complex than just doing it the old-fashioned way. So why bother? why should an application like Facebook care to verify whether you want to modify your own settings or send a friend request? Because privacy is mission-critical for Facebook, and an exploit that allows me to send a friend request to myself as you is an unmitigated disaster for them. And trivial to do in a mostly-client world. Beyond trivial if I have access to the other client, which I am one browser bug or open wifi access point away from having. It can be, provided that it's only in the form of new features And those new features are going to be written in what? Since your MVP's framework doesn't support server-side logic, you're now splitting your code in three. Now you're either in maintenance or rewrite hell, just as you're taking off. That's not one of the good problems to have, it's one of the stupid problems you should have avoided by laying the right foundations at the start.
    - buu700 15y ago
      How are you going to verify the password without a server? Only a dreadfully insecure system would choose to compare plain text passwords over the standard practice of hashing. It makes no difference if the hash is done client-side or server-side; if anything, even with SSL it's more secure to keep the plain text password removed from the network. ACLs fine-grained enough to handle modern security scenarios are going to be just as complex as doing traditional validation. How so? If I can manage my Facebook privacy settings graphically, any developer can manage ACLs in a DB schema graphically. No reason to unnecessarily clutter up code and deal with pointless architectural issues. Because privacy is mission-critical for Facebook, and an exploit that allows me to send a friend request to myself as you is an unmitigated disaster for them. And trivial to do in a mostly-client world. Beyond trivial if I have access to the other client, which I am one browser bug or open wifi access point away from having. Uh, what? If you have access to someone else's account then the game is already lost; no backend can solve that. Since your MVP's framework doesn't support server-side logic, you're now splitting your code in three. Now you're either in maintenance or rewrite hell, just as you're taking off. ...What? Who says whatever framework I use won't support server-side logic? Even vanilla JavaScript or jQuery is fine for AJAX calls. Not sure where you're getting "rewrite hell" from, but you must really hate the client APIs provided by Google, Yahoo, Facebook, and Microsoft.