Georgia Tech at USENIX Security 2018

Atlanta   |   Aug. 15, 2018

Four new cybersecurity discoveries were presented by the Georgia Institute of Technology (Georgia Tech) at the 27th USENIX Security Symposium (USENIX '18) in Baltimore.

Georgia Tech submitted recent research in the areas of web applications, information tracking, and new attacks against cryptographic methods. The highly competitive conference includes universities from Asia, Europe, the Middle East and North America, as well as work by scientists at industry giants Google, Microsoft, Samsung, Siemens and others. Just 100 projects by 125 organizations were accepted.

Professor Taesoo Kim served on the conference's program committee, and organized the Malware Track. His research team also earned the "Distinguished Paper Award" for their work that created a new fuzzing technique called QSYM that is finer, faster and found 14x more bugs than other popular fuzzing tools.

In one project presented at USENIX, researchers from Georgia Tech helped close a security vulnerability that could have allowed hackers to steal encryption keys from a popular security package by briefly listening in on unintended “side channel” signals from smartphones. The side channel attack -- dubbed "One & Done" -- is believed to be the first to retrieve the secret exponent of an encryption key in a modern version of OpenSSL without relying on the cache organization and/or timing.

“This is something that could be done at an airport to steal people’s information without arousing suspicion and makes the so-called ‘coffee shop attack’ much more realistic,” said Milos Prvulovic, associate chair of Georgia Tech’s School of Computer Science. “The designers of encryption software now have another issue that they need to take into account because continuous snooping over long periods of time would no longer be required to steal this information.”

The work was supported in part by the National Science Foundation, the Defense Advanced Research Projects Agency (DARPA), and the Air Force Research Laboratory (AFRL).

USENIX is organized by the Advanced Computing Systems Association. It was founded in 1975 under the name "Unix Users Group," to study and develop Unix and similar systems. The USENIX Association today is a nonprofit professional organization that makes research and conference proceedings freely available under an open-access policy.


Research by Georgia Tech


Track 1: Web Applications

Rampart: Protecting Web Applications from CPU-Exhaustion Denial-of-Service Attacks

In collaboration with University of Texas at Dallas and the University of California, Santa Barbara

Wei Meng, Chinese University of Hong Kong (alumnus - Georgia Tech); Chenxiong Qian, Georgia Tech; Shuang Hao, University of Texas at Dallas; Kevin Borgolte, Giovanni Vigna, and Christopher Kruegel, University of California, Santa Barbara; Wenke Lee, Georgia Tech

Denial-of-Service (DoS) attacks pose a severe threat to the availability of web applications. Traditionally, attackers have employed botnets or other amplification techniques to exhaust a targeted web server, and, consequently, prevent it from responding to legitimate visitor requests. However, more recently, highly sophisticated DoS attacks have emerged in which a single, carefully crafted request results in significant resource consumption and ties up a web application for a non-negligible amount of time. Unfortunately, these attacks require only a few requests to overwhelm the target, which makes them difficult to detect -- even with state-of-the-art detection systems.

In this paper, we present "Rampart," which is a defense that protects web applications from sophisticated CPU-exhaustion DoS attacks. Rampart detects and stops sophisticated CPU-exhaustion DoS attacks using statistical methods and function-level program profiling. Furthermore, it synthesizes and deploys filters to block subsequent attacks, and it adaptively updates them to minimize any potentially negative impact on legitimate users.

We implemented Rampart as an extension to the PHP Zend engine. Rampart has negligible performance overhead and it can be deployed for any PHP application without having to modify the application’s source code. To evaluate Rampart’s effectiveness and efficiency, we demonstrate that it protects two of the most popular web applications, WordPress and Drupal, from real-world and synthetic CPU-exhaustion DoS attacks. We also show that Rampart preserves web server performance with a low false-positive rate and a low false-negative rate.



Track 2: Attacks on Crypto & Crypto Libraries

One&Done: A Single-Decryption EM-Based Attack on OpenSSL’s Constant-Time Blinded RSA

Monjur Alam, Haider Adnan Khan, Moumita Dey, Nishith Sinha, Robert Callan, Alenka Zajic, and Milos Prvulovic, Georgia Tech

This paper presents the first side-channel-attack approach that, without relying on the cache organization and/or timing, retrieves the secret exponent from a single decryption on arbitrary ciphertext in a modern (current version of OpenSSL) fixed-window constant-time implementation of RSA. Specifically, the attack recovers the exponent’s bits during modular exponentiation from analog signals that are unintentionally produced by the processor as it executes the constant-time code that constructs the value of each “window” in the exponent, rather than the signals that correspond to squaring/multiplication operations and/or cache behavior during multiplicand table lookup operations. The approach is demonstrated using electromagnetic (EM) emanations on two mobile phones and an embedded system, and after only one decryption in a fixed-window RSA implementation, it recovers enough bits of the secret exponents to enable very efficient (within seconds) reconstruction of the full, private RSA key.

Since the value of the ciphertext is irrelevant to our attack, the attack succeeds even when the ciphertext is unknown and/or when message randomization (blinding) is used. Our evaluation uses signals obtained by demodulating the signal from a relatively narrow band (40 MHz) around the processor’s clock frequency (around 1GHz), which is within the capabilities of compact sub-$1,000 software-defined radio (SDR) receivers.

Finally, we propose a mitigation where the bits of the exponent are only obtained from an exponent in integer-sized groups (tens of bits) rather than obtaining them one bit at a time. This mitigation is effective because it forces the attacker to attempt recovery of tens of bits from a single brief snippet of signal, rather than having a separate signal snippet for each individual bit. This mitigation has been submitted to OpenSSL and was merged into its master source code branch prior to the publication of this paper.

QSYM : A Practical Concolic Execution Engine Tailored for Hybrid Fuzzing

Insu Yun, Sangho Lee, and Meng Xu, Georgia Tech; Yeongjin Jang, Oregon State University (alumnus - Georgia Tech); Taesoo Kim, Georgia Tech

Recently, hybrid fuzzing has been proposed to address the limitations of fuzzing and concolic execution by combining both approaches. The hybrid approach has shown its effectiveness in various synthetic benchmarks such as DARPA Cyber Grand Challenge (CGC) binaries, but it still suffers from scaling to find bugs in complex, real-world software. We observed that the performance bottleneck of the existing concolic executor is the main limiting factor for its adoption beyond a small-scale study.

To overcome this problem, we design a fast concolic execution engine, called QSYM, to support hybrid fuzzing. The key idea is to tightly integrate the symbolic emulation with the native execution using dynamic binary translation, making it possible to implement more fine-grained, so faster, instruction-level symbolic emulation. Additionally, QSYM loosens the strict soundness requirements of conventional concolic executors for better performance, yet takes advantage of a faster fuzzer for validation, providing unprecedented opportunities for performance optimizations, e.g., optimistically solving constraints and pruning uninteresting basic blocks.

Our evaluation shows that QSYM does not just outperform state-of-the-art fuzzers (i.e., found 14× more bugs than VUzzer in the LAVA-M dataset, and outperformed Driller in 104 binaries out of 126), but also found 13 previously unknown security bugs in eight real-world programs like Dropbox Lepton, ffmpeg, and OpenJPEG, which have already been intensively tested by the state-of-the-art fuzzers, AFL and OSS-Fuzz.

Pictured Above: USENIX Security Program Co-Chairs Adrienne Porter Felt of Google (L) and William Enck of North Carolina State University (R) present the 2018 "Distinguished Paper Award" to Meng Xu, Sangho Lee, Insu Yun, Taesoo Kim, and Yeongjin Jang of Georgia Tech.



Track 3: Information Tracking

Enabling Refinable Cross-Host Attack Investigation with Efficient Data Flow Tagging and Tracking

Yang Ji, Sangho Lee, Mattia Fazzini, Joey Allen, Evan Downing, Taesoo Kim, Alessandro Orso, and Wenke Lee, Georgia Tech

Investigating attacks across multiple hosts is challenging. The true dependencies between security-sensitive files, network endpoints, or memory objects from different hosts can be easily concealed by dependency explosion or undefined program behavior (e.g., memory corruption). Dynamic information flow tracking (DIFT) is a potential solution, but, existing DIFT techniques only track information flow within a single host and lack an efficient mechanism to maintain and synchronize the data-flow tags globally across multiple hosts.

In this paper, we propose "RTAG," an efficient, data-flow tagging and tracking mechanism that enables practical cross-host attack investigations. RTAG is based on three novel techniques. First, by using a record-and-replay technique, it decouples the dependencies between different data-flow tags from the analysis, enabling lazy synchronization between independent and parallel DIFT instances of different hosts. Second, it takes advantage of system call-level provenance information to calculate and allocate the optimal tag map in terms of memory consumption. Third, it embeds tag information into network packets to track cross-host data flows -- requiring less than 0.05% network bandwidth overhead. Evaluation results show that RTAG is able to recover the true data flows of realistic cross-host attack scenarios. Performance wise, RTAG reduces the memory consumption of DIFT-based analysis by up to 90% and decreases the overall analysis time by 60%–90% compared with previous investigation systems.


About Cybersecurity at Georgia Tech

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The Institute for Information Security & Privacy (IISP) at Georgia Tech is a coordinating body for cybersecurity research; as a gateway to faculty, students, and scientists at Georgia Tech, and as a central location for collaboration around six, critical research thrusts: AttributionCyber-physical systems, Policy, Privacy Engineering, Risk, and Trust. By leveraging intellectual capital from across Georgia Tech and its external partners, we address vital solutions for national defense, economic continuity, and individual freedom. Working in partnership with the IISP, government and industry partners can help move Georgia Tech's cybersecurity research into deployable solutions that close the innovation gap with immediate application in the world. For research or partnership opportunities, contact: Gloria Griessman




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