In collaboration with IBM

CyberRank: Knowledge Elicitation for Risk Assessment of Database Security

H Grushka-Cohen, O Sofer, O Biller, B Shapira, L Rokach

Proceedings of the 25th ACM International on Conference on Information and Knowledge Management

Security systems for databases produce numerous alerts about
anomalous activities and policy rule violations. Prioritizing these
alerts will help security personnel focus their efforts on the most
urgent alerts. Currently, this is done manually by security experts
that rank the alerts or define static risk scoring rules. Existing
solutions are expensive, consume valuable expert time, and do not
dynamically adapt to changes in policy.
Adopting a learning approach for ranking alerts is complex due to
the efforts required by security experts to initially train such a
model. The more features used, the more accurate the model is
likely to be, but this will require the collection of a greater amount
of user feedback and prolong the calibration process. In this paper,
we propose CyberRank, a novel algorithm for automatic preference
elicitation that is effective for situations with limited experts’ time
and outperforms other algorithms for initial training of the system.
We generate synthetic examples and annotate them using a model
produced by Analytic Hierarchical Processing (AHP) to bootstrap
a preference learning algorithm. We evaluate different approaches
with a new dataset of expert ranked pairs of database transactions,
in terms of their risk to the organization. We evaluated using
manual risk assessments of transaction pairs, CyberRank outperforms all other methods for cold start scenario with error reduction of 20%.