An Alternative Approach To Computer System Security Monitoring And Enhancement Through System Call Sequence Analysis

Modern computer systems are plagued with stability and security problems: applications lose data, web servers are hacked, and systems crash under heavy load. Many of these problems or anomalies arise from rare program behavior caused by attacks or errors. A substantial percentage of the web-based attacks are due to buffer overflows. Many methods have been devised to detect and prevent anomalous situations that arise from buffer overflows. The current state-of-art of anomaly detection systems is relatively primitive and mainly depend on static code checking to take care of buffer overflow attacks. For protection, Stack Guards and I-leap Guards are also used in wide varieties.This dissertation proposes an anomaly detection system, based on frequencies of system calls in the system call trace. System call traces represented as frequency sequences are profiled using sequence sets. A sequence set is identified by the starting sequence and frequencies of specific system calls. The deviations of the current input sequence from the corresponding normal profile in the frequency pattern of system calls is computed and expressed as an anomaly score. A simple Bayesian model is used for an accurate detection.Experimental results are reported which show that frequency of system calls represented using sequence sets, captures the normal behavior of programs under normal conditions of usage. This captured behavior allows the system to detect anomalies with a low rate of false positives. Data are presented which show that Bayesian Network on frequency variations responds effectively to induced buffer overflows. It can also help administrators to detect deviations in program flow introduced due to errors.

Novetats Millennium 2009

Conferència emmarcada dins el 2on Workshop Biblioteca UdG: La Universitat de Girona davant els reptes del nou Espai Europeu d'Educació Superior, on s'exposen les últimes novetats del programa Millennium referent a les estadístiques, Url checker, materials booking, scheduler

Canvi de sistema del catàleg de la Biblioteca de la UdG: introducció a Millennium

Es parla del que va suposar canviar de sistema de gestió de biblioteques, de VTLS a Millennium. Es fa un resum de les actuacions precanvi, del calendari d'implementació i formació, les dates clau. I, per últim, es donen alguns exemples de catàlegs: University of California i la Universidad Complutense

The statistical estimation of throughput and turnaround functions for a university computer system /

Vita.

Run time support for the TUTOR language on a small computer system /

"UILU-ENG 77 1719."

Illiac III computer system manual : arithmetic units; volume 2 /

Author of vol. 1 is Daniel E. Atkins.

Illiac III computer system manual: taxicrinic processor,

At head of title: COO-2118-0001.

Application of the fault-tolerant deadline mechanism to a satellite on-board computer system /

"June 1980."

A computer simulation of a large scale academic computer system.

Thesis (M.S.)--University of Illinois.

Illiac III computer system manual: arithmetic units

"C00-1018-1194."

Illiac III computer system manual : taxicrinic processor, volume 2 /

"This work was supported by Contract AT(11-1)-1018 with the U.S. Atomic Energy Commission through September 30, 1970. Current support is under Contract AV(11-1)-2118 with the above agency."

Dynamic reconfiguration in a modular computer system /

"This report reproduces a thesis of the same title submitted to the Department of Electrical Engineering, Massachusetts Institute of Technology, in partial fulfillment of the requirements for the degree of Doctor of Philosophy, May 1971."--p. 3

Organizational maintenance repair parts and special tools list for battery computer system AN/GYK-29(V).

Includes index.

Direct support maintenance repair parts and special tools list for battery computer system AN/GYK-29(V).

Includes index.

The Computer System for the Estimation of the Realizability of the Crew Activity Algorithms

When designing specification on-board algorithm (the algorithm, realized on on-board digital computing machine, and algorithm to activity of the crew necessary to conduct the estimation their realizing. Presented computer system allows in interactive mode with user to value the temporary expenseses of the operator on processes decision making and their realizing, participations it in process of the spying.