apply clem comments

PhD/research_proposal/introduction.tex

@@ -14,7 +14,7 @@
 
 
 
-A wide variety of solutions are available to protect embedded.
+A wide variety of solutions are available to protect embedded systems.
 No solution can claim to protect against all possible attacks, and multiple layers of prevention, detection, and mitigation mechanisms are often required to protect a system as best as possible.
 Each solution presents different domains of application, requirements, and capabilities that are important to understand to reduce the attack surface.
 
@@ -25,26 +25,26 @@ If the \gls{ids} only considers local resources (e.g. CPU load, RAM data, disks
 \glspl{hids} have access to relevant local data, but they require to install software on the target --- either for collection only or for local analysis --- or dedicated components in communication with the target.
 This requirement represents a flaw for two main reasons.
 First, the host machine may be compromised, allowing the attacker to bypass the detection by feeding forged data to the \gls{ids}, shutting it down, or forging the detection result.
-Second, the operation of the \gls{hids} may interfere with the critical operation of the system (for example, if the \gls{hids} misbehave and block other operations).
-For these reasons, \gls{hids} may be challenging to implement on a wide range of embedded systems and lack the reliability of an external solution.
+Second, the operation of the \gls{hids} may interfere with the critical operation of the system (for example, if the \gls{hids} misbehaves and blocks other operations).
+For these reasons, \glspl{hids} may be challenging to implement on a wide range of embedded systems and lack the reliability of an external solution.
 
 One other main class of \gls{ids} takes a different approach to solving some of these issues.
-\gls{nids} consider the communication between machines in a network to detect intrusions.
+\glspl{nids} consider the communication between machines in a network to detect intrusions.
 This solution does not require installing individual software on each machine and can detect network-level intrusions. 
-However, \gls{nids} present their own drawbacks.
+However, \glspl{nids} present their own drawbacks.
 First, machine-specific attacks can remain undetected as only network information is accessible.
 Then, they require the installation of dedicated equipment to collect network traffic.
-Finally, modern traffic encryption practices will limit the \gls{nids} to sender-receiver pattern analysis unless traffic flows unencrypted, which can raise privacy issues.
+Finally, modern traffic encryption practices will limit \glspl{nids} to sender-receiver pattern analysis unless traffic flows unencrypted, which can raise privacy issues.
 
 The current \gls{ids} scene appears to present a tradeoff between the granularity of detection and isolation from the protected machine.
 What about the case of protecting a machine against a local intrusion without the possibility of installing additional software?
 How can an \gls{ids} protect a machine against attackers bypassing the secure boot verification and booting a completely different \gls{os}?
-Following the discovery of a vulnerability on a \gls{scs}, how can the detection mechanism evolve without requiring the re-certification of the whole system?
+Following the discovery of a vulnerability on a \gls{scs}, how can the detection mechanism evolve without requiring the recertification of the whole system?
 These use cases can seem niche, but they represent a reality for many purpose-built embedded systems with minimal \gls{os}. 
 Systems like network switches, \gls{rtu}, \gls{wap} rarely allow additional software installation and yet perform critical tasks.
 In these cases, neither local resources nor network information can be leveraged for local attack detection.
 Moreover, any industry that relies on \gls{scs} have strict regulations (e.g. DO-178C for aerospace systems in Canada, ISO 26262 for automotive system, ISO 16142 for medical devices) that guarantee the safety of every equipment.
-Modifying an existing system to add intrusion detection capabilities is expensive as it requires the re-validation of the whole system.
+Modifying an existing system to add intrusion detection capabilities is expensive as it requires the revalidation of the whole system.
 
 A third under-exploited source of information for embedded systems activity is the side-channels.
 The side-channels are all the physical emissions that a machine involuntarily generates.
@@ -52,7 +52,7 @@ For example, the sound of a fan, the temperature of a CPU, or the power consumpt
 
 \begin{figure}[H]
     \centering
-    \includegraphics[width=\linewidth]{images/side_channel}
+    \includegraphics[width=0.95\linewidth]{images/side_channel.pdf}
     \caption{Main side-channels from a typical embedded systems.}
     \label{fig:side_channel}
 \end{figure}
@@ -70,16 +70,17 @@ This proposal is organized as follows: Section~\ref{sec:related-work} presents a
 The idea of side-channel-based analysis traces back to the seminal work by Paul C. Kocher.
 He introduced \gls{dpa} to find secret keys used by cryptographic protocols in tamper-resistant devices~\cite{kocher1999differential}.
 This led to a field of research focusing on side-channel analysis that has grown ever since.
-A wide variety of side-channels have since been leveraged to recover information from a system such as power consumption \cite{brier2004correlation,mangard2008power}, electromagnetic fields~\cite{sayakkara2019survey}, acoustic emanations~\cite{7479068, alevi2015keyboard}, thermal dissipations~\cite{9727162} or, on the non-physical side, cache~\cite{page2003defending}.
+A wide variety of side-channels have since been leveraged to recover information from a system such as power consumption \cite{brier2004correlation,mangard2008power}, electromagnetic fields~\cite{sayakkara2019survey}, acoustic emanations~\cite{7479068, halevi2015keyboard}, thermal dissipations~\cite{9727162} or, on the non-physical side, cache~\cite{page2003defending}.
+
 
 Among them, power consumption is the most common and widely studied side-channel because of its numerous advantages.
-Power consumption leaks information about the activity of an embedded system with little inertia --- i.e., it can transmit high-frequency information contrary to thermal ---, is easy to measure with low-cost equipment at specific points in a machine --- contrary to electromagnetic fields or sound --- and is guaranteed to be present in any system.
+Power consumption leaks information about the activity of an embedded system with little inertia --- i.e., it can transmit high-frequency information contrary to thermal ---, is easy to reliably measure with low-cost equipment --- contrary to electromagnetic fields or sound --- and is guaranteed to be present in any system.
 This combination of properties allows for a granular detection of a system activity, even at the instruction level.
 %Quisquater et al.~\cite{quisquater2002automatic} present an approach to identify instructions with the use of self-organizing maps, power analysis and analysis of electromagnetic traces.\agd{this citation comes out of nowhere}
 %Eisenbarth et al.~\cite{eisenbarth2010building} propose a methodology for recovering the instruction flow of microcontrollers using its power consumption.\agd{this citation comes out of nowhere}
 
 
-Even though the information potential of side-channel analysis enables powerful attacks, it also enables defensive capabilities.
+Even though the information-gathering capability of side-channel analysis enables powerful attacks, it also enables defensive capabilities.
 Zhai et al.~\cite{zhai2015method} propose a self-organizing maps approach that uses features extracted from an embedded processor to detect abnormal behaviour in embedded devices. 
 Different teams at Georgia Tech University leveraged power and electromagnetic backscattering \cite{8701559, jorgensen2022efficient} to detect hardware trojans and counterfeit integrated circuits.
 Due to its non-intrusive and architecture-agnostic nature, power fingerprinting has a wide range of applications from energy production systems \cite{6378346}, Software Defined Radio compliance assessments \cite{5379826}, or applications activity on mobile devices \cite{8057232}.
@@ -90,12 +91,12 @@ In this work, they use the power consumption of a given embedded system to ident
 The team builds on their previous technique and presents a new one~\cite{Moreno2018} using the power consumption of embedded systems for non-intrusive online run-time monitoring through anomaly detection.
 They use a signals and systems analysis approach to identify anomalies using the power consumption of a system and showcase this by identifying buffer overflow attacks on their system. 
 Msgna et al.~\cite{msgna2014verifying} propose a technique for using the instruction-level power consumption of a system to verify the integrity of the software components of a system with no prior knowledge of the software code.
-In~\cite{kur2009improving}, Kur et al. perform power analysis of smart cards based on the JavaCard platform to help identify vulnerable operations, obtain bytecode instruction information, and also propose a framework to replace vulnerable operations with safe alternatives.\\
+In~\cite{kur2009improving}, Kur et al. perform power analysis of smart cards based on the JavaCard platform to help identify vulnerable operations, obtain bytecode instruction information, and also propose a framework to replace vulnerable operations with safe alternatives.
 
-Side-channel information's non-intrusiveness and difficult-to-forge nature make it an ideal input for \gls{ids} systems.
-Van Aubel et al.~\cite{van2018side} proposed using electromagnetic information to protect \gls{ics} by detecting changes in software flow.
+Side-channel information's non-intrusiveness and difficult-to-forge nature makes it an ideal input for \glspl{ids}.
+Van Aubel et al.~\cite{van2018side} proposed using electromagnetic information to protect \glspl{ics} by detecting changes in software flow.
 Xun et al.~\cite{10016748} use the voltage signal of a vehicle CAN bus to detect anomalies without extensive documentation from the manufacturer.
-On a different kind of embedded systems, Liang et al. propose a framework to leverage side-channel information in additive manufacturing where traditional \gls{ids} would fail.
+On a different kind of embedded systems, Liang et al. propose a framework to leverage side-channel information in additive manufacturing where traditional \glspl{ids} would fail.
 
 In more recent literature, there is a trend towards using \gls{ml} for side-channel analysis to enhance the security of systems.
 Michele Giovanni Calvi~\cite{calvi2019runtime} offers a solution for run-time monitoring of an entire cyber-physical system treated as a black box.