RE: J2EE EJB privacy leak and DOS.

["Alan Rouse" <ARouse () n2bb com>]

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:sbt13 () cryogenic net] 
Sent: Monday, October 14, 2002 1:43 AM
To: bugtraq () securityfocus com
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.