WOOT '19 Workshop Program

All sessions will be held in Grand Ballroom FGH unless otherwise noted.

Papers are available for download below to registered attendees now and to everyone beginning Monday, August 12, 2019. Paper abstracts are available to everyone now. Copyright to the individual works is retained by the author[s].

Downloads for Registered Attendees
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Attendee Files 
WOOT '19 Attendee List (PDF)
WOOT '19 Paper Archive (ZIP)

Monday, August 12

8:00 am–9:00 am

Continental Breakfast

Grand Ballroom Foyer

9:00 am–9:15 am

Opening Remarks and Awards

Program Co-Chairs: Alex Gantman, Qualcomm, and Clémentine Maurice, CNRS, IRISA

9:15 am–10:15 am

Invited Talk

Trends and Challenges in the Vulnerability Mitigation Landscape

Matt Miller, Microsoft

The software vulnerability landscape has changed dramatically over the past 20+ years. During this period, we’ve gone from easy-to-exploit stack buffer overruns to complex-and-expensive chains of multiple exploits. To better understand this evolution, this presentation will describe the vulnerability mitigation strategy Microsoft has been pursuing and will show how this strategy has influenced vulnerability and exploitation trends over time. This retrospective will form the basis for discussing some of the vulnerability mitigation challenges that exist today and the strategic shifts that Microsoft is exploring to address those challenges.

10:15 am–10:45 am

Break with Refreshments

Grand Ballroom Foyer

10:45 am–12:45 pm

Going Sideways

Session Chair: Daniel Gruss, Graz University of Technology

Taking a Look into Execute-Only Memory

Marc Schink and Johannes Obermaier, Fraunhofer Institute for Applied and Integrated Security (AISEC)

Available Media

The development process of microcontroller firmware often involves multiple parties. In such a scenario, the Intellectual Property (IP) is not protected against adversarial developers which have unrestricted access to the firmware binary. For this reason, microcontroller manufacturers integrate eXecute-Only Memory (XOM) which shall prevent an unauthorized read-out of third-party firmware during development. The concept allows execution of code but disallows any read access to it. Our security analysis shows that this concept is insufficient for firmware protection due to the use of shared resources such as the CPU and SRAM. We present a method to infer instructions from observed state transitions in shared hardware. We demonstrate our method via an automatic recovery of protected firmware. We successfully performed experiments on devices from different manufacturers to confirm the practicability of our attack. Our research also reveals implementation flaws in some of the analyzed devices which enables an adversary to bypass the read-out restrictions. Altogether, the paper shows the insufficient security of the XOM concept as well as several implementations.

Cross-Router Covert Channels

Adar Ovadia, Rom Ogen, Yakov Mallah, Niv Gilboa, and Yossi Oren, Ben-Gurion University of the Negev

Available Media

Many organizations protect secure networked devices from non-secure networked devices by assigning each class of devices to a different logical network. These two logical networks, commonly called the host network and the guest network, use the same router hardware, which is designed to isolate the two networks in software.

In this work we show that logical network isolation based on host and guest networks can be overcome by the use of cross-router covert channels. Using specially-crafted network traffic, these channels make it possible to leak data between the host network and the guest network, and vice versa, through the use of the router as a shared medium. We performed a survey of routers representing multiple vendors and price points, and discovered that all of the routers we surveyed are vulnerable to at least one class of covert channel. Our attack can succeed even if the attacker has very limited permissions on the infected device, and even an iframe hosting malicious JavaScript code can be used for this purpose. We provide several metrics for the effectiveness of such channels, based on their pervasiveness, rate and covertness, and discuss possible ways of identifying and preventing these leakages.

Two methods for exploiting speculative control flow hijacks

Andrea Mambretti, Northeastern University; Alexandra Sandulescu, Matthias Neugschwandtner, Alessandro Sorniotti, and Anil Kurmus, IBM Research - Zurich

Available Media

Touted as the buffer overflows of the age, Spectre and Meltdown have created significant interest around microarchitectural vulnerabilities and have been instrumental for the discovery of new classes of attacks. Yet, to-date, real-world exploits are rare since they often either require gadgets that are difficult to locate, or they require the ability of the attacker to inject code. In this work, we uncover two new classes of gadgets with very few restrictions on their structure, making them suitable for real-world exploitation. We demonstrate -- through PoCs -- their suitability to leak one bit and one byte respectively per successful attack, achieving high success rates and low noise on the constructed side-channel. We test our attack PoC on various kernels with default mitigations enabled, showing how they are insufficient to protect against them. We also show that hardening the configuration of mitigations successfully prevents exploitation, making a case for their wider adoption.

How Sharp is SHARP ?

Dixit Kumar, Chavhan Sujeet Yashavant, and Biswabandan Panda, IIT Kanpur; Vishal Gupta, Manipal University Jaipur and IIT Kanpur

Available Media

Cross-core last-level cache based side-channel attacks are becoming practical, affecting all forms of computing devices like mobiles, desktops, servers, and cloud based systems. Mitigating last-level cache based side channel attacks has become an active area of research and many proposals target to mitigate cross-core based conflict attacks. Secure Cache Hierarchy Aware Replacement Policy (SHARP) is one of the recent proposals that mitigate the conflict attacks by changing the underlying last-level cache replacement policy. Though SHARP is an elegant proposal; there are many subtle points, which were not part of the original SHARP proposal that appeared in the ISCA ’17. Through this paper, we discuss and debate the subtle issues that are left unanswered in the original SHARP paper.

12:45 pm–2:00 pm

Monday Luncheon

Terra Courtyard

2:00 pm–3:00 pm

Invited Talk

Behind CGC: A DARPA Cyber Grand Challenge White Team Retrospective

Paul Makowski, Narf Industries

DARPA hosted the final event for the Cyber Grand Challenge (CGC) at DEF CON 24 (August 2016), culminating a multi-year effort undertaken by teams spanning academia, industry and government. The goal of the challenge was to create automatic defensive systems capable of reasoning about flaws, formulating patches and deploying the patches on a network in real time. The Challenge was a catalyst for advances in autonomous program analysis, patch synthesis, verification, and much more. Tools and data produced for the CGC continue to aid state of the art advances today. In this talk I'll provide a behind-the-scenes retrospective of DARPA’s CGC: designing challenges with the goal of advancing autonomous program analysis, hardening infrastructure and game mechanics to ensure agreement between game performance and program goals, data-mining the CGC Final Event (CFE) for televised stories, and the lasting impact of the Challenge. The views, opinions, and/or findings expressed are those of the author(s) and should not be interpreted as representing the official views or policies of the Department of Defense or the U.S. Government.

3:00 pm–3:30 pm

Break with Refreshments

Grand Ballroom Foyer

3:30 pm–5:30 pm

Breaking and Entering

Session Chair: Natalie Silvanovich, Google

Defeating Cisco Trust Anchor: A Case-Study of Recent Advancements in Direct FPGA Bitstream Manipulation

Jatin Kataria, Rick Housley, Joseph Pantoga, and Ang Cui, Red Balloon Security

Available Media

Field-programmable gate arrays (FPGAs) are widely used in real-time, data-intensive, and mission critical system designs. In the space of trusted computing, FPGA-based security modules have appeared in a number of widely used security conscious devices. The Cisco Trust Anchor module (TAm) is one such example that is deployed in a significant number of enterprise network switches, routers, and firewalls. We discuss several novel direct FPGA bitstream manipulation techniques that exploit the relative simplicity of input and output pin configuration structures.

We present an analysis of the efficacy of Cisco TAm and discuss both the high-level architectural flaws of the TAm as well as implementation specific vulnerabilities in a TAm protected Cisco router. By combining techniques presented in this paper with other recent advancements in FPGA bitstream manipulation, we demonstrate the feasibility of reliable remote exploitation of all Cisco TAms implemented using Xilinx Spartan-6 FPGAs. The TAm exploit described in this paper allows the attacker to fully bypass all Trust Anchor functionality, including hardware-assisted secure boot, and to stealthily inject persistent malicious implants within both the TAm FPGA and the application processor. Lastly, we discuss the applicability of our bitstream manipulation techniques to other FPGA-based devices and propose several practical mitigations.

RISC-V: #AlphanumericShellcoding

Hadrien Barral and Rémi Géraud-Stewart, DIENS, École normale supérieure, CNRS, PSL University, Paris, France; Georges-Axel Jaloyan, DIENS, École normale supérieure, CNRS, PSL University, Paris, France/CEA, DAM, DIF, F-91297 Arpajon, France; David Naccache, DIENS, École normale supérieure, CNRS, PSL University, Paris, France

Artifact Evaluated - Passed
Available Media

We explain how to design RISC-V shellcodes capable of running arbitrary code, whose ASCII binary representation use only letters a-zA-Z, digits 0-9, and either of the three characters: #,/,'.

Vacuums in the Cloud: Analyzing Security in a Hardened IoT Ecosystem

Fabian Ullrich, Jiska Classen, Johannes Eger, and Matthias Hollick, Secure Mobile Networking Lab, TU Darmstadt, Germany

Available Media

With the advent of robot vacuum cleaners, mobile sensing platforms entered millions of homes. These gadgets not only put "eyes and ears" into formerly private spaces, but also communicate gathered information into the cloud. Furthermore, they reside inside the customer's local network. Hence, they are a prime target for attacks and if compromised become a privacy and security nightmare. Vendors are aware of robots being a target of interest; they employ various security mechanisms against tampering with devices and recorded data in the cloud.

In this paper, the Neato BotVac Connected and Vorwerk Kobold VR300 ecosystems are analyzed and the robot firmware is reverse engineered. To achieve the latter, a technique to bypass the devices' secure boot process is presented revealing the firmware, which is then dissected to evaluate device-specific secret key generation and to trace vulnerabilities. We present flaws in the secret key generation and provide insight on the occurrence and exploitation of a buffer overflow, which give an attacker complete control not only in the local network but also via the robots' cloud interface. Eventually, multiple attacks based on the findings are described and security implications are discussed. We shared our findings with the vendors, who further increased their otherwise commendable security mechanisms, and hope more vendors can take away valuable lessons from this highly complex Internet of Things (IoT) ecosystem.

Unicorefuzz: On the Viability of Emulation for Kernelspace Fuzzing

Dominik Maier, Benedikt Radtke, and Bastian Harren, TU Berlin

Artifact Evaluated - Passed
Available Media

Fuzzing uncovers an ever-growing number of critical vulnerabilities. Despite the simple concept—execute the target until it crashes—setting up fuzz tests can pose complex challenges. This is especially true for code that cannot run as part of a userland process on desktop operating systems—for example device drivers and kernel components. In this paper, we explore the use of CPU emulation to fuzz arbitrary parsers in kernelspace with coverage-based feedback. We propose and open-source Unicorefuzz and explain merits and pitfalls of emulation-based fuzzing approaches. The viability of the approach is evaluated against artificial Linux kernel modules, the Open vSwitch network virtualization component as well as bugs originally uncovered by syzcaller. Emulator-based fuzzing of kernel code is not very complex to set up and can even be used to fuzz operating systems and devices for which no source code is available.

5:45 pm–6:45 pm

Monday Happy Hour

Terra Courtyard

Sponsored by Carnegie Mellon University Privacy Engineering
Mingle with other attendees while ­enjoying snacks and beverages. Attendees of all co-located events taking place on Monday are welcome.

Tuesday, August 13

8:00 am–9:00 am

Continental Breakfast

Grand Ballroom Foyer

9:00 am–10:00 am

Invited Talk

Computer Security for Victims of Intimate Partner Violence

Thomas Ristenpart, Cornell Tech

In this talk I will survey our work on understanding and improving technology’s role in intimate partner violence (IPV). IPV is a widespread social ill affecting about one in four women and one in ten men at some point in their lives. In interviews with survivors and the professionals that work with them in New York City, our research has provided the most granular view to date of technology abuse in IPV contexts. Abusers install spyware on mobile devices, compromise victim accounts, exploit social media for harassment, and much more. We complemented this qualitative work with first-of-their-kind measurement studies that discovered a large ecosystem of online resources aimed at helping abusers, including a variety of apps usable as IPV spyware.

Unfortunately, abusers require little technology expertise to mount devastating attacks. Instead, the context of IPV undermines the assumptions underlying traditional security mechanisms such as passwords and malware detection, and, more broadly, we believe traditional approaches to computer security are not yet up to the task of helping IPV victims. We have therefore initiated work on building up a theory and practice of clinical computer security, in which trained technology professionals meet with victims to help diagnose digital insecurities and advise on potential remediations. I will discuss our ongoing field work prototyping clinical services, including deployment of a new spyware detection tool in New York City, and conclude with a discussion of other domains where clinical computer security may prove useful.

This is covering joint work with: Rahul Chatterjee, Nicola Dell, Peri Doerfler, Sam Havron, Karen Levy, Damon McCoy, Diana Minchala, Hadas Orgad, and Jackeline Palmer.

10:00 am–10:30 am

Break with Refreshments

Grand Ballroom Foyer

10:30 am–12:30 pm

Town Called Malice

Session Chair: Alex Gantman, Qualcomm

A better zip bomb

David Fifield

Awarded Best Paper!

Artifact Evaluated - Passed
Available Media

We show how to construct a non-recursive zip bomb that achieves a high compression ratio by overlapping files inside the zip container. "Non-recursive" means that it does not rely on a decompressor's recursively unpacking zip files nested within zip files: it expands fully after a single round of decompression. The output size increases quadratically in the input size, reaching a compression ratio of over 28 million (10 MB → 281 TB) at the limits of the zip format. Even greater expansion is possible using 64-bit extensions. The construction uses only the most common compression algorithm, DEFLATE, and is compatible with most zip parsers.

D-TIME: Distributed Threadless Independent Malware Execution for Runtime Obfuscation

Jithin Pavithran, Milan Patnaik, and Chester Rebeiro, Indian Institute of Technology Madras

Artifact Evaluated - Passed
Available Media

An important aspect of malware design is to be able to evade detection. This is increasingly difficult to achieve with powerful runtime detection techniques based on behavioural and heuristic analysis. In this paper, we propose D-TIME, a new distributed threadless independent malware execution framework to evade runtime detection.

D-TIME splits a malware executable into small chunks of instructions and executes one chunk at a time in the context of an infected thread. It uses a Microsoft Windows feature called Asynchronous Procedure Call (APC) to facilitate chunk invocation; shared memory to coordinate between chunk executions; and a novel Semaphore based Covert Broadcasting Channel (SCBC) for communication between various chunk executions. The small size of the chunks along with the asynchronous nature of the execution makes runtime detection difficult, while the coordinated execution of the chunks leads to the intended malign action. D-TIME is designed to be self-regenerating ensuring high resilience of the system.

We evaluate D-TIME on a Microsoft Windows system with six different malware and demonstrate its undetectability with 10 different anti-virus software. We also study the CPU usage and its influence on Performance Counters.

Breaking Turtles All the Way Down: An Exploitation Chain to Break out of VMware ESXi

Hanqing Zhao, Chaitin Security Research Lab; Georgia Institute of Technology; Yanyu Zhang, Chaitin Security Research Lab; Kun Yang, Tsinghua University; Taesoo Kim, Georgia Institute of Technology

Available Media

VMware ESXi is an enterprise-class, bare-metal hypervisor dedicated to providing the state-of-the-art private-cloud infrastructures. Accordingly, the design and implementation of ESXi is of our community’s interest, yet lacking a thorough evaluation of its security internals. In this paper, we give a comprehensive analysis of the guest-to-host attack surfaces of ESXi and its recent security mitigation (i.e., the vSphere sandbox). In particular, we introduce an effective and reliable approach to chain multiple vulnerabilities for exploitation and demonstrate our approach by leveraging two new bugs (i.e., uninitialized stack usages), namely, CVE-2018-6981 and CVE-2018-6982. Our exploit chain is the first public demonstration of a virtual machine escape against VMware ESXi.

Alternative (ab)uses for HTTP Alternative Services

Trishita Tiwari and Ari Trachtenberg, Boston University

Available Media

The HTTP Alternative Services header (Alt-Svc) was introduced in 2013 in a bid to streamline load balancing, protocol optimizations, and client segmentation, and it has since been subsequently implemented in almost all mobile and desktop browsers. We show that the major implementations of the header are independently susceptible to a variety of stealthy abuse. Indeed, we demonstrate how Alternative Services may be leveraged to scan ports blacklisted by browsers, probe firewalled hosts, and mount Distributed Denial of Service attacks. These services may also be misused to bypass popular phishing and malware protection services like Safe Browsing, and also online site checkers like VirusTotal, URLVoid, Sucuri and IPVoid. In the privacy realm, the Alt-Svc header may be abused for user tracking: at the network layer by Internet Service Providers (ISPs), and at the application layer by first and third party websites (where we bypass third-party tracking protections on Firefox, Chrome and Brave). In a similar manner, the header may be used by transiently connected ISPs to exfiltrate parts of a victim's browser history. Our attacks work, to varying extents, on Firefox, Tor, Chrome, and Brave browser, and have been disclosed accordingly--so far, one of our vulnerabilities been patched by Mozilla as CVE-2019-11728. We conclude with proposed mitigations for some of these abuses.

12:30 pm–12:45 pm

Guest Presentation

Rode0day: A Year of Bug-Finding Evaluations

Andrew Fasano, Northeastern University

Why are some bugs so hard to find? Why are some bug-finding tools more effective than others? How can we improve bug-finding tools? In May 2018, we launched Rode0day, a monthly bug-finding competition designed to answer these questions. In our first year of competitions, we injected thousands of synthetic bugs into more than 50 programs, evaluated 35 bug-finders as they searched for bugs, and collected information on when teams found bugs as well as properties of the bugs themselves. In this talk we will present our analysis of this data and use it identify strengths and weaknesses of tools, discuss what properties of an injected bug make it easy or hard, and suggest ways of improving bug-finders.

12:45 pm–2:00 pm

Tuesday Luncheon

Terra Courtyard

2:00 pm–3:00 pm

Invited Talk

Shooting Cryptographic Fish in a Barrel

Nadia Heninger, University of California, San Diego

Cryptography has traditionally been considered to be one of the strong points of computer security. However, a number of the public-key cryptographic algorithms that we use are fragile in the face of implementation mistakes or misunderstandings. In this talk, I will survey "weapons of math destruction" that have been surprisingly effective in finding broken cryptographic implementations the wild.

3:00 pm–4:00 pm

Crypto Means...

Who Spent My EOS? On the (In)Security of Resource Management of EOS.IO

Sangsup Lee, Daejun Kim, Dongkwan Kim, Sooel Son, and Yongdae Kim, KAIST

Available Media

EOS is a popular cryptocurrency, whose market cap is over seven billion USD. Its ecosystem operates in the EOS.IO system, which is devised to speed up the slow transaction rate of previous blockchain technologies. Whereas many previous studies have investigated the security issues of Bitcoin and Ethereum, the security of EOS.IO has thus far drawn little attention despite its popularity. Even the studies that have addressed the security of EOS and its underlying blockchain system mostly focused on implementational bugs in the core of the EOS.IO system or in smart contracts, rather than addressing the fundamental problems stemming from the EOS.IO design.

To address this void in the previous literature, we investigate the design architecture of EOS.IO. Based on this investigation, we introduce four attacks whose root causes stem from the unique characteristics of EOS.IO, including intentionally slowing down the block creation time—which can disrupt the essential functions of its blockchain and incapacitate the entire EOS.IO system. In addition, we find that an adversary can partially freeze the execution of a target smart contract or maliciously consume all the resources of a target user with crafted requests. We report all the identified threats to the EOS.IO foundation, one of which is confirmed to be fatal. Finally, we discuss possible mitigations against the proposed attacks.

Distributed Password Hash Computation on Commodity Heterogeneous Programmable Platforms

Branimir Pervan and Josip Knezovic, University of Zagreb Faculty of Electrical Engineering and Computing; Katja Pericin, ReversingLabs Ltd.

Artifact Evaluated - Passed
Available Media

In this paper, we present the Cool Cracker Cluster cCc: a heterogeneous distributed system for parallel, energy-efficient, and high-speed bcrypt password hash computation. The cluster consists of up to 32 heterogeneous nodes with Zynq-7000-based SoCs featuring a dual-core, general-purpose ARM processor coupled with FPGA programmable logic. Each node uses our custom bcrypt accelerator which executes the most costly parts of the hash computation in programmable logic.

We integrated our bcrypt implementation into John the Ripper, an open source password cracking software. Message Passing interface (MPI) support in John the Ripper is used to form a distributed cluster. We tested the cluster, trying different configurations of boards (Zedboards and Pynq boards), salt randomness, and cost parameters finding out that password cracking scales linearly with the number of nodes. In terms of performance (number of computed hashes per second) and energy efficiency (performance per Watt), cCc outperforms current systems based on high-end GPU cards, namely Nvidia Tesla V100, by a factor of 2.72 and 5 respectively.

4:00 pm–4:30 pm

Break with Refreshments

Grand Ballroom Foyer

4:30 pm–5:30 pm

Let's Get Physical

Session Chair: Yossi Oren, Ben Gurion University of the Negev

MIN()imum Failure: EMFI Attacks against USB Stacks

Colin O'Flynn, Dalhousie University

Available Media

Electromagnetic Fault Injection (EMFI) allows generation of faults in a target device without needing to physically modify the target. This paper uses EMFI to recover secret data from two devices without opening the enclosure of the devices, making the attack possible without leaving any physical evidence. This is demonstrated on two devices: a Trezor bitcoin wallet and a Solo Key open-source FIDO2 authentication key.

The specific vulnerable code attacked with EMFI is part of the USB stack. The attack allows a host-provided value of wLength to be used in reading back up to 64~Kbyte of memory from the target device. Examples of this vulnerability are given for three popular general-purpose RTOSes.

To assist with evaluation of this attack, the open-source PhyWhisperer-USB hardware is also introduced. This tool provides hardware USB decoding and pattern matching to allow cycle-accurate fault injection timing.

Automatic Wireless Protocol Reverse Engineering

Johannes Pohl and Andreas Noack, University of Applied Sciences Stralsund

Artifact Evaluated - Passed
Available Media

Internet of Things manufacturers often implement their own wireless protocols in order to save licensing fees. Deviating from standard, however, sometimes paves the way for critical attacks such as stolen cars or house breaks without physical traces. For a security analysis of such proprietary protocols, researchers use Software Defined Radios and dedicated demodulation tools. But when reverse engineering is necessary, researchers are left alone and need to find protocol fields manually in a time-consuming and tedious process.

We contribute a framework designed for field inference of wireless protocols. In contrast to previous research, our algorithm operates on the physical layer and, moreover, takes wireless specifics such as Received Signal Strength Indicators into account. Furthermore, the algorithm is robust against errors that are common in wireless communication. Our contribution not only performs a bootstrap of completely unknown protocols but also considers prior knowledge such as participant addresses or known field positions in order to increase accuracy. An implementation is published as part of the open source software Universal Radio Hacker and is a first step towards a default security analysis for proprietary wireless protocols similar like a port-scan is for traditional security.

6:00 pm–7:00 pm

Tuesday Happy Hour

Terra Courtyard

Sponsored by Intel
Mingle with other attendees while ­enjoying snacks and beverages. Attendees of USENIX Security '19 and all co-located events are welcome.