Discovering Attackers Past Behavior to Generate Online Hyper-Alerts

To support information security, organizations deploy Intrusion Detection Systems (IDS) that monitor information systems and networks, generating alerts for every suspicious behavior. However, the huge amount of alerts that an IDS triggers and their low-level representation make the alerts analysis a challenging task. In this paper, we propose a new approach based on hierarchical clustering that supports intrusion alert analysis in two main steps. First, it correlates historical alerts to identify the most common strategies attackers have used. Then, it associates upcoming alerts in real time according to the strategies discovered in the first step. The experiments were performed using a real dataset from the University of Maryland. The results showed that the proposed approach could properly identify the attack strategy patterns from historical alerts, and organize the upcoming alerts into a smaller amount of meaningful hyper-alerts

FK 506 pre-treatment is associated with reduced levels of tumor necrosis factor and interleukin 6 following hepatic ischemia/reperfusion

Using a rat model, the effect of pre-treatment with FK 506 on hepatic ischemia/reperfusion injury was investigated. All control animals died within 72 h of the ischemia/reperfusion injury. Pre-treatment of the animals with FK 506 (0.3 mg/kg in 0.5 ml saline) administered intravenously improved survival. The most striking protection against fatal ischemia/reperfusion injury was achieved in rats that were given FK 506 6 and 24 h prior to the induction of the hepatic ischemic insult (70% and 80% 10-day survival rates, respectively). The hepatoprotective effect of FK 506 was assessed further in a second experiment in which the serum levels of tumor necrosis factor (TNF) and interleukin 6 (IL-6) were measured. These results suggest that a 60-min period of hepatic ischemia and subsequent reperfusion triggers the release of both TNF and IL-6, and that FK 506 pre-treatment (6 h before the ischemic episode) significantly inhibits the production and/or release of these two cytokines compared to untreated controls. These data provide additional information concerning the immunosuppressive and hepatoprotective activities of FK 506. Based upon these data, it is probable that FK 506 attenuates hepatic ischemia/reperfusion injury, at least in part, by reducing TNF and IL-6 levels. © 1993 Elsevier Scientific Publishers Ireland Ltd. All rights reserved