Hyoungjun Koo

Despite decades of research on software diversification, only address space layout randomization has seen widespread adoption. Code randomization, an effective defense against return-oriented programming exploits, has remained an academic exercise mainly due to i) the lack of a transparent and streamlined deployment model that does not disrupt existing software distribution norms, and ii) the inherent incompatibility of program variants with error reporting, whitelisting, patching, and other ope

Traffic differentiation---giving better (or worse) performance to certain classes of Internet traffic---is a well-known but poorly understood traffic management policy. There is active discussion on whether and how ISPs should be allowed to differentiate Internet traffic, but little data about current practices to inform this discussion. Previous work attempted to address this problem for fixed line networks; however, there is currently no solution that works in the more challenging mobile envir

With legitimate code becoming an attack surface due to the proliferation of code reuse attacks, software debloating is an effective mitigation that reduces the amount of instruction sequences that may be useful for an attacker, in addition to eliminating potentially exploitable bugs in the removed code. Existing debloating approaches either statically remove code that is guaranteed to not run (e.g., non-imported functions from shared libraries), or rely on profiling with realistic workloads to p

Binary code similarity detection (BCSD) serves as a basis for a wide spectrum of applications, including software plagiarism, malware classification, and known vulnerability discovery. However, the inference of contextual meanings of a binary is challenging due to the absence of semantic information available in source codes. Recent advances leverage the benefits of a deep learning architecture into a better understanding of underlying code semantics and the advantages of the Siamese architectur

The concept of destructive code reads is a new defensive strategy that prevents code reuse attacks by coupling fine-grained address space layout randomization with a mitigation for online knowledge gathering that destroys potentially useful gadgets as they are disclosed by an adversary. The intuition is that by destroying code as it is read, an adversary is left with no usable gadgets to reuse in a control-flow hijacking attack. In this paper, we examine the security of this new mitigation. We s

Today, a web browser plays a crucial role in offering a broad spectrum of web experiences. The most popular browser, Chromium, has become an extremely complex application to meet ever-increasing user demands, exposing unavoidably large attack vectors due to its large code base. Code debloating attracts attention as a means of reducing such a potential attack surface by eliminating unused code. However, it is very challenging to perform sophisticated code removal without breaking needed functiona

Code diversification is an effective mitigation against return-oriented programming attacks, which breaks the assumptions of attackers about the location and structure of useful instruction sequences, known as "gadgets". Although a wide range of code diversification techniques of varying levels of granularity exist, most of them rely on the availability of source code, debug symbols, or the assumption of fully precise code disassembly, limiting their practical applicability for the protection of

A series of thermoplastic elastomer (TPE) systems with an ABA-type triblock structure, derived from renewable resources, were prepared using an eco-friendly approach, subsequently developed to demonstrate industrial applications ranging from pressure-sensitive adhesive (PSA) to elastomer, and structurally broken by degradation process. First, α,ω-dihydroxy poly(δ-hexalactone)s (PHLs) as a rubbery block (B), which could be derived from vegetable-oil, were precisely synthesized with target M n val

Reverse engineering of a stripped binary has a wide range of applications, yet it is challenging mainly due to the lack of contextually useful information within. Once debugging symbols (e.g., variable names, types, function names) are discarded, recovering such information is not technically viable with traditional approaches like static or dynamic binary analysis. We focus on a function symbol name recovery, which allows a reverse engineer to gain a quick overview of an unseen binary. The key

A wide range of binary analysis applications, such as bug discovery, malware analysis and code clone detection, require recovery of contextual meanings on a binary code. Recently, binary analysis techniques based on machine learning have been proposed to automatically reconstruct the code representation of a binary instead of manually crafting specifics of the analysis algorithm. However, the existing approaches utilizing machine learning are still specialized to solve one domain of problems, re

A function recognition problem serves as a basis for further binary analysis and many applications. Although common challenges for function detection are well known, prior works have repeatedly claimed a noticeable result with a high precision and recall. In this paper, we aim to fill the void of what has been overlooked or misinterpreted by closely looking into the previous datasets, metrics, and evaluations with varying case studies. Our major findings are that i) a common corpus like GNU util

A smart contract is a self-executing program on a blockchain to ensure an immutable and transparent agreement without the involvement of intermediaries. Despite its growing popularity for many blockchain platforms like Ethereum, no technical means is available even when a smart contract requires to be protected from being copied. One promising direction to claim a software ownership is software watermarking. However, applying existing software watermarking techniques is challenging because of th

Decompilation is a process of converting a low-level machine code snippet back into a high-level programming language such as C. It serves as a basis to aid reverse engineers in comprehending the contextual semantics of the code. In this respect, commercial decompilers like Hex-Rays have made significant strides in improving the readability of decompiled code over time. While previous work has proposed the metrics for assessing the readability of source code, including identifiers, variable name

The ease of reproducibility of digital artifacts raises a growing concern in copyright infringement; in particular, for a software product. Software watermarking is one of the promising techniques to verify the owner of licensed software by embedding a digital fingerprint. Developing an ideal software watermark scheme is challenging because i) unlike digital media watermarking, software watermarking must preserve the original code semantics after inserting software watermark, and ii) it requires

The recovery of contextual meanings on a machine code is required by a wide range of binary analysis applications, such as bug discovery, malware analysis, and code clone detection. To accomplish this, advancements on binary code analysis borrow the techniques from natural language processing to automatically infer the underlying semantics of a binary, rather than replying on manual analysis. One of crucial pipelines in this process is instruction normalization, which helps to reduce the number