RE: J2EE EJB privacy leak and DOS.

From: Alan Rouse (ARouseat_private)
Date: Tue Oct 15 2002 - 08:36:45 PDT

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    Without more details, it sounds to me as if an attacker would first have
    to deploy her own code in the EJB server, before she could attack the
    target user's objects.  If the attacker has that capability, can't she
    accomplish the same end with or without this vulnerability?
    
    Or is there a way to exploit this without the attacker having power to
    deploy her own code?
    
    -----Original Message-----
    From: Sylvia [mailto:sbt13at_private] 
    Sent: Monday, October 14, 2002 1:43 AM
    To: bugtraqat_private
    Subject: J2EE EJB privacy leak and DOS.
    
    
    Hi,
    
    I've contacted Sun twice about this, and they've not responded to me.
    
    The EJB security model associates roles with users, and controls their 
    access to object methods based on those roles.
    
    Where the object is a stateful session object, any user can access it, 
    provided they have the necessary roles. This is true even if the object
    was 
    created by a different user. This means that information private to one 
    user can be accessed by another. There is also a DOS available because
    any 
    user can destroy the object.
    
    The EJB client is not meant to change its security association, but
    neither 
    of the implementations I've tested enforce this. The EJB specification
    does 
    not actually require the server to do so.
    
    To access the object, a user's client needs to know the IOR. However, on
    
    the implementations I've tested, IORs are allocated in a trivial way
    that 
    makes it simple to derive new valid IORs from an existing valid one.
    
    Sylvia.
    



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