| 1. |
- Krüger, Kristin, et al.
(author)
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Randomization as Mitigation of Directed Timing Inference Based Attacks on Time-Triggered Real-Time Systems with Task Replication
- 2021
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In: Leibniz Transactions on Embedded Systems. - 2199-2002.
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Journal article (peer-reviewed)abstract
- Time-triggered real-time systems achieve deterministic behavior using schedules that are constructed offline, based on scheduling constraints. Their deterministic behavior makes time-triggered systems suitable for usage in safety-critical environments, like avionics. However, this determinism also allows attackers to fine-tune attacks that can be carried out after studying the behavior of the system through side channels, targeting safety-critical victim tasks. Replication -- i.e., the execution of task variants across different cores -- is inherently able to tolerate both accidental and malicious faults (i.e. attacks) as long as these faults are independent of one another. Yet, targeted attacks on the timing behavior of tasks which utilize information gained about the system behavior violate the fault independence assumption fault tolerance is based on. This violation may give attackers the opportunity to compromise all replicas simultaneously, in particular if they can mount the attack from already compromised components. In this paper, we analyze vulnerabilities of time-triggered systems, focusing on safety-certified multicore real-time systems. We introduce two runtime mitigation strategies to withstand directed timing inference based attacks: (i) schedule randomization at slot level, and (ii) randomization within a set of offline constructed schedules. We evaluate these mitigation strategies with synthetic experiments and a real case study to show their effectiveness and practicality.
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| 2. |
- Thakur, Chandni, et al.
(author)
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Assessment of Hydrological Changes in Godavari River Basin Under the Impacts of El-Niño
- 2024
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In: Proceedings of the International Association of Hydrological Sciences (PIAHS). - : Copernicus Publications. - 2199-899X. ; 385, s. 203-209
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Journal article (peer-reviewed)abstract
- El Niño–Southern Oscillation (ENSO) is the most prominent driver of the inter-annual variability of Indian summer monsoon rainfall (ISMR). This study focuses on understanding the hydrological variations in Godavari River Basin (GRB) due to the weakening of ISMR during El Niño years (1980–2008), using the variable infiltration capacity (VIC) model. The entire basin was discretized into 1325 uniform grids of resolution 0.15°×0.15° (about 16.65 km), and hydrological parameters of the basin were analysed at each grid level for various El Niño events. Based on the Oceanic Niño Index (ONI), obtained from National Oceanic and Atmospheric Administration (NOAA), El Niño events occurred in the past were subclassified into weak (2004 and 2006), moderate (1986, 1994 and 2002), strong (1987 and 1991) and very strong (1982, 1987) events. For this study, VIC model was run for the period 1980–2008 and a composite of El Niño and normal years (1981, 1985, 1989, 1990, 1992, 1993, 1996, 2001 and 2003) was prepared to assess the impacts of El Niño events on the hydrology of GRB. Our results showed a negative correlation of precipitation, abstractions and soil moisture with the increasing magnitude of El Niño events. The quantum of precipitation was reduced during El Niño years compared to normal years, which showed the basin's exposure to more frequent droughts during El Niño events.
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