Security: Session Identifier Not Updated in tcl

Question

I\'m working on open-source application \"Project-Open\" and during the scanning I got the following vulnerability:

[Medium] Session Identifier Not Updated
Issue         


        

Answer 1

There is a fix in OpenACS 5.9 that addresses your scanning reports. Please see the following discussion on OpenACS.org for reference.

http://www.openacs.org/forums/message-view?message_id=5332821

Answer 2

The problem that the OWASP report is talking about is the inability to migrate a session to use a new ID, making it easier for an attacker to discover the ID and reuse it. The protection against this is to change the session ID from time to time (no, I don't know how often!) and that Java code is involved in doing just that.

A session is represented as a token stored in the browser, usually in a cookie (and this is what cookies are designed to do). That token is then used to look up the database record corresponding to the session, which holds serializations of the key/value mappings in the session. It's a simple mechanism, but very powerful. The Java code for doing all this will be fairly complex behind the scenes because of the serialization, etc., but Tcl values are (usually, and always for built-in types) naturally serializable and so should prove much less of a problem in this; copying a session to a new key could be done without having to deserialize in the first place.

The exact code for doing this depends on the framework in use. I don't know what ]project-open[ uses, so that's as far as we can drill right now. You need to talk to other people actually working on PO…

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For all that, the best way would be to make the key given to clients not be the primary key, so that you can change the session key without having to delete things. Just have a session key column (with an index!) and you'll be able to make things work fine. This is a more sophisticated approach though; it might not be practical to implement in your environment..