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Information flow tracking was proposed more than 40 years ago to address the limitations of access control mechanisms to guarantee the confidentiality and integrity of information flowing within a system, but has not yet been widely applied in practice for security solutions. Here, we survey and systematize literature on dynamic information flow tracking (DIFT) to discover challenges and opportunities to make it practical and effective for security solutions. We focus on common knowledge in the literature and lingering research gaps from two dimensions— (i) the layer of abstraction where DIFT is implemented (software, software/hardware, or hardware) and (ii) the security goal (confidentiality and/or integrity). We observe that two major limitations hinder the practical application of DIFT for on-the-fly security applications: (i) high implementation overhead and (ii) incomplete information flow tracking (low accuracy). We posit, after review of the literature, that addressing these major impedances via hardware parallelism can potentially unleash DIFT’s great potential for systems security, as it can allow security policies to be implemented in a built-in and standardized fashion. Furthermore, we provide recommendations for the next generation of practical and efficient DIFT systems with an eye towards hardware-supported implementations. 

Dynamic Information Flow Tracking (DIFT), also called Dynamic Taint Analysis (DTA), is a technique for tracking the information as it flows through a program's execution. Specifically, some inputs or data get tainted and then these taint marks (tags) propagate usually at the instruction-level. While DIFT has been a fundamental concept in computer and network security for the past decade, it still faces open challenges that impede its widespread application in practice; one of them being the indirect flow propagation dilemma: should the tags involved in an indirect flow, e.g., in a control or address dependency, be propagated? Propagating all these tags, as is done for direct flows, leads to overtainting (all taintable objects become tainted), while not propagating them leads to undertainting (information flow becomes incomplete). In this paper, we analytically model that decisioning problem for indirect flows, by considering various tradeoffs including undertainting versus overtainting, importance of heterogeneous code semantics and context. Towards tackling this problem, we design MITOS, a distributed-optimization algorithm, that: decides about the propagation of indirect flows by properly weighting all these tradeoffs, is of low-complexity, is scalable, is able to flexibly adapt to different application scenarios and security needs of large distributed systems. Additionally, MITOS is applicable to most DIFT systems that consider an arbitrary number of tag types, and introduces the key properties of fairness and tag-balancing to the DIFT field. To demonstrate MITOS's applicability in practice, we implement and evaluate MITOS on top of an open-source DIFT, and we shed light on the open problem. We also perform a case-study scenario with a real in-memory only attack and show that MITOS improves simultaneously (i) system's spatio-temporal overhead (up to 40%), and (ii) system's fingerprint on suspected bytes (up to 167\%) compared to traditional DIFT, even though these metrics usually conflict. 

Attacks which combine software vulnerabilities and hardware vulnerabilities are emerging security problems. Although the runtime verification or remote attestation can determine the correctness of a system, existing methods suffer from inflexible security policy setup and high performance overheads. Meanwhile, they rarely focus on addressing the threat in the RISC-V architecture, which provides an open Instruction Set Architecture (ISA) of the processsor. In this paper, we propose a comprehensive software and hardware co-verification method to protect the entire RISC-V system in the runtime. The proposed method adopts the Dynamic Information Flow Tracking (DIFT) framework to implement a new Verifier and Prover security architecture for supporting runtime software and hardware coverification. We realize a FPGA prototype on the Rocket-Chip, an RISC-V open-source processor core. The framework is implemented as a co-processor which do not change the architecture of main processor core and the new security architecture can be integrated with other RISC-V processors. 

As computing devices become more commonplace in every day life, we have seen an increase of possible attacks on commercial devices and critical infrastructure. As a result, both academia and industry have proposed solutions to mitigate or outright eliminate the ever expanding set of viable targets. Initially, this resulted in an influx of software-based defenses against these emerging threats. Unfortunately, it was found that software solutions could be bypassed with more advanced attacks and often resulted in high performance overhead. As such, hardware-assisted security defenses have been developed to provide improved security while keeping performance overhead to manageable levels, especially for IoT devices. In this paper, we will provide a survey of prominent hardware-assisted security defenses. We will enumerate the attacks these defenses aim to protect, as well as their effectiveness. We will also discuss the implications in both performance and system design. A comparison between approaches that target the same set of issues, and possible directions for future research will be presented. 

By 2018, it is no secret to the global networking community: Internet of Things (IoT) devices, usually controlled by IoT applications and applets, have dominated human lives. It has been shown that popular applet platforms (including If This Then That (IFTTT)) are susceptible to attacks that try to exfiltrate private photos, leak user location, etc. As new attacks might show up very frequently, tracking them fast and in an efficient and scalable manner is a daunting task due to the limited (e.g., memory, energy) resources at the IoT/mobile device and the large network size. Towards that direction, in this paper we propose a decentralized Dynamic Information Flow Tracking (DDIFT) framework that overcomes these challenges, better adapts to the IoT context, and further, is able to illuminate IoT applet attacks. In doing so, we leverage the synergy between: (i) a dynamic information flow tracking module that considers the application of tags with different types along with provenance information and runs in the mobile device at a fast timescale, (ii) a forensics analysis module running in the cloud at a slow timescale, (iii) distributed optimization to optimize various functionalities of the above modules as well as their interaction. We show that our framework is able to detect IoT applet attacks with higher accuracy (on average 81% improvement for different URL upload attack scenarios) and decreases resource wastage (on average 71% less memory usage under different integrity attack scenarios) compared to traditional DIFT, opening new horizons for IoT privacy and security. 

By 2018, it is no secret to the global networking community: Internet of Things (IoT) devices, usually controlled by IoT applications and applets, have dominated human lives. It has been shown that popular applet platforms (including If This Then That (IFTTT)) are susceptible to attacks that try to exfiltrate private photos, leak user location, etc. As new attacks might show up very frequently, tracking them fast and in an efficient and scalable manner is a daunting task due to the limited (e.g., memory, energy) resources at the IoT/mobile device and the large network size. Towards that direction, in this paper we propose a decentralized Dynamic Information Flow Tracking (DDIFT) framework that overcomes these challenges, better adapts to the IoT context, and further, is able to illuminate IoT applet attacks. In doing so, we leverage the synergy between: (i) a dynamic information flow tracking module that considers the application of tags with different types along with provenance information and runs in the mobile device at a fast timescale, (ii) a forensics analysis module running in the cloud at a slow timescale, (iii) distributed optimization to optimize various functionalities of the above modules as well as their interaction. We show that our framework is able to detect IoT applet attacks with higher accuracy (on average 81% improvement for different URL upload attack scenarios) and decreases resource wastage (on average 71% less memory usage under different integrity attack scenarios) compared to traditional DIFT, opening new horizons for IoT privacy and security.