A lot of your problems are because you don't seem to have any idea how Java enterprise or web applications (of any kind) work with sessions - which is a totally separate issue from GWT. I suggest reading up on this prior to trying to use sophisticated frameworks like GWT/GAE. It is usually better to understand the basics of the underlying technology prior to using the most abstract ones.
1) You do not need to send any session id (unless you have some application token - to mitigate XSRF attacks for example). The web container will send the session id in the response header. This session id is kept in the browser memory. The browser maps the cookie id to the originating domain. When making requests to the originating domain, the browser automatically will put the session id in the request headers. Look at the response/request headers yourself. 2) You do not 'set a timeout' on a session id or touch it or whatever else you think you do. This is typically a server/domain configuration parameter. Prior to worrying about regenerating session ids during the course of a session - learn the basics. On Apr 27, 7:55 pm, John Denley <[email protected]> wrote: > OK, I think Im getting somewhere with all this, thanks so much for your > input Sri! > > Essentially all I need is an interim solution until GAE supports SSL. We are > actually not going to be storing data thats likely to be particularly > exciting for any hacker, the best they can hope for is a list of addresses > of people who use any one hairdresser in any one town! > > Regarding the "5 points" (Which I think we can now cut down to just one (the > use of sessions) going forward!) > > 1. I understand that any kind of encryption on the client is effectively > pointless without SSL, but its always going to be better than nothing! A > bit > like saying that hding your front door key under a rock in your neighbours > front garden is no different to leaving it in your front door........ > 2. I figured TLS was something like SSL, either way its not on GAE yet, > so I cant use it yet! > 3. My passwords are being salted and hashed > (jBcrypt<http://www.mindrot.org/projects/jBCrypt/>) > before being stored. > 4. & 5. Still not sure i get how sessions really work. Ill keep reading > and trying to figure it out. But surely at some point I still need to send > the session ID from the server to the client right? As far as I can tell so > far, the session ID is generated on the server, so the right thing to do it > set a timeout on that sessionID and "touch" it every time the user makes a > call to the server, making sure that the sessionID has not timed out. There > are mentions in various places that you should "refresh/regenerate" the > sessionID on a regular basis during a logged in session, to keep it > fresh..... > > On 27 April 2010 10:16, Sripathi Krishnan <[email protected]>wrote: > > > > > If you can recommend a security framework that works with App Engine and > >> custom URL's without SSL/HTTPS and has really good documentsation for > >> complete dummies then please do let me know.... > > > As far as I know, the above is impossible. You cannot have security without > > ssl. You cannot have a custom domain *and* ssl *and* GAE (because it is > > prohibitively expensive for google). And you have already starred the GAE > > issue that speaks about > > it<http://code.google.com/p/googleappengine/issues/detail?id=792>, > > so there really isn't anything new for me to add. > > If you cannot use google's authentication, and if you can't use any of the > > (not-so-secure) workarounds described in that issue, I am afraid there is no > > way you can use GAE. I'd recommend discussing this in GAE discussion thread > > to get ideas from people. Either that, or just wait till GAE starts > > supporting SSL. > > > Additional responses to your comments > > > 1. It doesn't matter what encryption method you use on client side; it > > may be the most secure algo on earth. The problem is with the key > > management. JS code needs the key to encrypt. And if it is in the JS > > code, > > an attacker will always be able to get it. Ofuscation is just a very > > minor > > hurdle, its easy to read through it. > > 2. TLS is transport layer > > security<http://en.wikipedia.org/wiki/Transport_Layer_Security>, > > which is essentially the new SSL. > > 3. On the server side as well - you should NOT encrypt passwords. > > Encryption means there is a way to decrypt and recover the password. If > > you > > can decrypt it, an attacker will find a way as well. The recommended way > > to > > store passwords is to Salt and Hash > > them<http://www.aspheute.com/english/20040105.asp> > > . > > 4. Sessions can loosely be described as 'per-user-server-side-hashmap'. > > The server automatically creates a cookie 'jsessionid' to track the > > user. So > > when you call request.getSession(), the container gets the session id > > from > > the jsessionid cookie and then gets the state corresponding to that > > sessionid. You should read more about this in the j2ee tutorial. > > 5. I'd recommend OWASPs guide to session > > management<http://www.owasp.org/index.php/Session_Management>. > > If you are interested in application security, OWASP is the best place to > > learn. > > > --Sri > > > On 27 April 2010 12:54, John Denley <[email protected]> wrote: > > >> Awesome response SRI, and with a bit of luck this will help all those > >> hundreds of people on here who are struggling with how to implement decent > >> security. > > >> Ive spent months wrestling with security, after finding out that Google > >> accounts doesnt have a good enough API for use with GWT/GAE.....and that > >> GAE > >> doesnt support SSL/HTTPS for custom URLs (eg in my casewww.ucanzoom.com) > > >> What struck me immediately is how easy it was for you to figure out what > >> my client side code was doing, esp given that GWT should be obfuscating the > >> code, which I thought would me making it pretty hard to actually "read my > >> source code"... > > >> Ill address your points individually and I would very much appreciate any > >> further feedback you are willing to give. > > >> 1. The client side encryption is just trying to make it as hard as > >> possible for "people like you";) to crack my password, ive had loads of > >> people say "theres no point doing client side encryption", but my > >> feeling is > >> that you have to do SOMETHING on the client side, even if it does only > >> take > >> a determined hacker half an hour to figure it out. At least im forcing > >> someone to consider whether or not its really worthwhile bothering to > >> spend > >> that time trying to crack my encryption. Even the fact that you have > >> referred to it as "some kind of encryption" makes me smile, as you are > >> right > >> in that I have created what i think is a pretty tough encryption. Id be > >> interested to hear what kinds of methods a determined hacker might use > >> to > >> crack it, as Im fairly happy that the only way to actually do that > >> would be > >> to examine the source code. I dont think that any kind of brute force > >> will > >> succeed, but Im reasonbly OK if brute force will work, as stated > >> earlier in > >> this response! Im not happy that you can find the "secret key" id > >> forgotten > >> to hide that... Ill get onto that ;) > >> 2. Ive never heard of TLS, but SSL is not currently available for > >> custom URLs on Google App Engine, which is why I cant use it. > >> Extracting the > >> password is something that worries me, however I am somewhat relying on > >> the > >> sessionID to provide a unique "connection" once the user has just > >> logged in > >> once (see some comments below on this) > >> 3. I am using a well recognised encryption algorithm on the server > >> side to actually store the passwords in Google App Engine Big table > >> (although Im reasonbly happy about the fact that Google datastore is > >> pretty > >> secure in its own right) > >> 4. I dont really understand session ID's and have not been able to > >> find a simple explaination anywhere on the web as to how they work. Im > >> not > >> actually planning on using cookies initially because of the potential > >> security issue. Is a session cookie automatically created? does it > >> store the > >> same sessionID as the server? > >> 5. how does the server know if im logged in or not? Actually, from > >> point 4, Im just guessing that you could store the session ID with a > >> timeout. Is that how it should be done? Checking it on the client side > >> is an > >> efficiency thing, no point in doing an RPC call if the client side > >> knows for > >> sure if the session is not logged in. The client side check is more of a > >> check that your logged out rather than a check that you are logged > >> in.... > > >> If you can recommend a security framework that works with App Engine and > >> custom URL's without SSL/HTTPS and has really good documentsation for > >> complete dummies then please do let me know.... > > >> Thank you SOO much for your input Sri, its really great to have had even > >> the feedback you have given me so far! > > >> John > > >> On 27 April 2010 04:46, Sripathi Krishnan > >> <[email protected]>wrote: > > >>> 1. You are doing some kind of encryption of passwords on the client > >>> side. Its a big mistake. Its easy to figure out how its being > >>> encrypted/hashed. In your case, the secret key is > >>> > >>> L87Y9*(yOFDMrsn};W/.XEPvSt]{uwl~,ozi34jQmT:@Rd)CZae2k|=6^I_+AG-[x01HBNpqUb? > >>> cJKV5fgh. > >>> The exact algorithm used for encryption is also extractable, just > >>> needs half > >>> an hour of determination. > >>> 2. Not using SSL/TLS is another big mistake. It is trivial for > >>> anybody to see the traffic an extract the password. Your custom > >>> password > >>> encryption algo (in 1 above) is not going to help at all. > >>> 3. I can't tell how you are storing passwords on the server side, but > >>> you must salt and hash your passwords. They must not be stored in a > >>> recoverable form. Also, use a strong hash function (SHA-1, for > >>> example). MD5 > >>> is broken, don't use it. And please do not create your own hash > >>> function, > >>> its not worth it. > >>> 4. Why do you have a RPC method getSessionID()? You don't need the > >>> sessionid in client side code. Just stick to the default session id > >>> that > >>> your application server provides. If you want to read the session > >>> identifier, pick it up from the cookie > >>> 5. I see there is a javascript check to see if the user is logged in > >>> or not. I hope you are doing it on the server side as well... Its > >>> useless to > >>> do the check on client side. > > >>> To summarize - please don't build authentication/authorization yourself. > >>> Its far easier and secure to use a framework. Once you get the basics > >>> right, > >>> go through the Security for GWT > >>> paper<http://groups.google.com/group/Google-Web-Toolkit/web/security-for-gw...>for > >>> additional information. > > >>> --Sri > > >>> On 27 April 2010 07:08, John V Denley <[email protected]>wrote: > > >>>> Ive > > ... > > read more » -- You received this message because you are subscribed to the Google Groups "Google Web Toolkit" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/google-web-toolkit?hl=en.
