Exu - A System for Secure Delegation of
Authority on an Insecure Network
Karl Ramm - Massachusetts Institute of Technology
Michael Grubb - Duke University
Abstract
Administration of a large and complex system poses several
problems: Usually, some tasks must be delegated due to lack of
qualified or trusted staff, and some tasks must be automated. In
many cases, some parts of the task might need special
credentials, such as Kerberos tickets or AFS tokens, that may not
necessarily be easily available to the person executing the task.
The problem is that most systems divide users into two groups:
haves and have nots, and provide no mechanism for finer-grained
access control. In addition, the tasks executed must be
carefully recorded for possible later auditing. Earlier
solutions, such as the setuid bit, Moira, ADM, and sysctl, can be
used to accomplish this, either in a limited or dangerous (in the
case of setuid) fashion. Exu proposes to solve the problem via
secure, authenticated connection to a server with full
authentication that can cause things to happen in real time.
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