The vulnerabilities that plague computers cause endless grief to users. Slammer compromised millions of hosts in minutes; a hit-list worm would take under a second. Recently proposed techniques respond better than manual approaches, but require expensive instrumentation, which limits deployment. Although spreading "antibodies" (e.g. signatures) ameliorates this limitation, hosts depending on antibodies are defenseless until inoculation; to the fastest hit-list worms this delay is crucial. Additionally, most recently proposed techniques cannot provide recovery to provide continuous service after an attack.

Diagnosing production run failures is a challenging yet importanttask. Most previous work focuses on offsite diagnosis, i.e.development site diagnosis with the programmers present. This is insufficient for production-run failures as: (1) it is difficult to reproduce failures offsite for diagnosis; (2) offsite diagnosis cannot provide timely guidance for recovery or security purposes; (3)it is infeasible to provide a programmer to diagnose every production run failure; and (4) privacy concerns limit the release of information(e.g. coredumps) to programmers.

The hyperlink induced topic search algorithm, which is a method of link analysis, primarily developed for retrieving information from the Web, is extended in this paper, in order to evaluate one aspect of quality in an object-oriented model. Considering the number of discrete messages exchanged between classes, it is possible to identify "God" classes in the system, elements which imply a poorly designed model. The principal eigenvectors of matrices derived from the adjacency matrix of a modified class diagram, are used to identify and quantify heavily loaded portions of an object-oriented design that deviate from the principle of distributed responsibilities. The non-principal eigenvectors are also employed in order to identify possible reusable components in the system. The methodology can be easily automated as illustrated by a Java program that has been developed for this purpose.