Login logistics

Question

I'm writing a suite of applications that all require login to a server. It's come together quite nicely, but I've run into a logistic snag. The nature of the applications require that they be closed and launched again later with some frequency. It is very annoying to have to login every time one of the applications needs to launch.

I'm trying to think of a secure way of perhaps having the login information stored on the local user's machine. Is there a good way to even go about that? Permissions protected config files? The registry? How does Firefox store its passwords? Have you ever had to do something like this?

The suite is more of a protocol than anything, all the applications are written in a variety of languages (Python, C#, Java, etc) and run on a variety of operating systems (Windows, Linux, OSX, etc). I'm not really looking for code examples, but more just general approaches to this problem. Is it wise to have locally stored passwords? How can you have a session login for a suite with such disparate components? Right now I use application.rc config files stored locally to each application, but they are plain text and far from secure.

Answer 1

Typically, this sort of thing is done by use of a "cookie"; a key which (securely) indicates that the user has successfully previously logged in to the server resource. This is how most web sites manage login information, and Firefox (all browsers, really) store the cookies that the browsers set on the user login. A few important things about cookies: they should be encrypted, to assure that malicious programs cannot generate one and thereby bypass the login process, they should match to server-kept resources (same reason), and they should age out, so that while you can maintain login information on a site for a while, your login information is not permanent (which is another security hole).

Answer 2

I'm going with Jeff on this one and assuming that since you mention the registry, you're referring to Windows. I'm also going to assume that you're talking about a desktop application (otherwise you could just use the builtin browser cookies to store the user's session).

Off the top of my head, I'd engineer the application so that when the user logs in to the server, the server returns a unique session id that identifies the authenticated user. I would then store than id along with an salted/encryped timestamp (which gives you the option of expiring the cached credentials).

The storage mechanism is up to you. You could store them in the HKEY_LOCAL_USERS section of the windows registry, or the Application Data folder in Windows. Both give you the option of user segmented storage.

Answer 3

Personally I would use an encrypted local config file with some sort of an ID value of the machine (motherboard ID, Chip ID, HD ID etc) as part of the encryption key so that the config file cant be just copied from one machine to another. I would also include the date and time so you can expire it when you decide it gets stale.

Alternatively, you can create a host exe or launcher that does the log in and then goes to sleep and wake it up each time you want to launch a new application. The host exe would take the application as a parameter and decide whether or not to ask for login credentials (usually when the first app is started and then keep the login user and an encrypted password in memory. When the host exe has exited the login info is forgotten and when you start up again the cycle starts over.)

Answer 4

Hi,

Tomcat 6 supports persistence/replication of sessions, so you should care about choosing the manager and configure it ;-)

More info: http://tomcat.apache.org/tomcat-6.0-doc/config/manager.html