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Accountable Javascript Code Delivery
Full text linkThe Internet is a major distribution platform for
web applications, but there are no effective transparency and
audit mechanisms in place for the web. Due to the ephemeral
nature of web applications, a client visiting a website has no
guarantee that the code it receives today is the same as yesterday,
or the same as other visitors receive. Despite advances in web
security, it is thus challenging to audit web applications before
they are rendered in the browser. We propose Accountable JS,
a browser extension and opt-in protocol for accountable delivery
of active content on a web page. We prototype our protocol,
formally model its security properties with the TAMARIN Prover,
and evaluate its compatibility and performance impact with case
studies including WhatsApp Web, AdSense and Nimiq.
Accountability is beginning to be deployed at scale, with
Meta’s recent announcement of Code Verify available to all 2
billion WhatsApp users, but there has been little formal analysis
of such protocols. We formally model Code Verify using the
TAMARIN Prover and compare its properties to our Accountable
JS protocol. We also compare Code Verify’s and Accountable JS
extension’s performance impacts on WhatsApp Web
TALUS: Reinforcing TEE Confidentiality with Cryptographic Coprocessors
Full text linkPlatforms are nowadays typically equipped with trusted execution environments (TEEs), such as Intel SGX or ARM TrustZone. However, recent microarchitectural attacks on TEEs repeatedly broke their confidentiality guarantees, including the leakage of long-term cryptographic secrets. These systems are typically also equipped with a cryptographic coprocessor, such as a TPM or Google Titan. These coprocessors offer a unique set of security features focused on safeguarding cryptographic secrets. Still, despite their simultaneous availability, the integration between these technologies is practically nonexistent, which prevents them from benefitting from each other’s strengths.
In this paper, we propose TALUS , a general design and a set of three main requirements for a secure symbiosis between TEEs and cryptographic coprocessors. We implement a proof-of-concept of TALUS based on Intel SGX and a hardware TPM. We show that with TALUS, the long-term secrets used in the SGX life cycle can be moved to the TPM. We demonstrate that our design is robust even in the presence of transient execution attacks, preventing an entire class of attacks due to the reduced attack surface on the shared hardware
Poster: From Hashes to Ashes – A Comparison of Transcription Services
No full textIn recent years, semi-structured interviews gained more and more importance in cyber-security research. Transcribing audio recordings of such interviews is a crucial step in qualitative data analysis, but it is also a work-intensive and time-consuming task. While outsourcing presents a common option, maintaining research quality requires precise transcriptions – a task further compounded by technical jargon and established expressions in the research field.
In this study, we compare different transcription services and evaluate their outcome quality within the context of cybersecurity. Our findings provide insights for researchers navigating the complex landscape of transcription services, offering informed choices to enhance the accuracy and validity of qualitative data analysis
Not Yet Another Digital ID: Privacy-Preserving Humanitarian Aid Distribution
No full textHumanitarian aid-distribution programs help bring physical goods (e.g., food, blankets) to people in need. Traditional paper-based solutions to support aid distribution do not scale to large populations and are hard to secure. Existing digital solutions solve these issues, at the cost of collecting large amount of personal information. Failing to protect aid recipients' privacy can result on harms for them and enables surveillance in the long run. In collaboration with the International Committee of the Red Cross, we build a safe aid-distribution system in this paper. We first systematize the requirements such a system should satisfy and then propose a decentralized solution based on the use of tokens. Our design provides strong scalability and accountability, at the same time, ensures privacy by design. We provide two instantiations of our design, on a smart card and on a smartphone. We formally prove the security and privacy properties of our design, and empirically show that the two instantiations can scale to hundreds of thousands of recipients
Space Odyssey: An Experimental Software Security Analysis of Satellites
Full text linkSatellites are an essential aspect of our modern society and have contributed significantly to the way we live today, most notable through modern telecommunications, global positioning, and Earth observation. In recent years, and especially in the wake of the New Space Era, the number of satellite deployments has seen explosive growth. Despite its critical importance, little academic research has been con- ducted on satellite security and, in particular, on the security of onboard firmware. This lack likely stems from by now outdated assumptions on achieving security by obscurity, effectively preventing meaningful research on satellite firmware.
In this paper, we first provide a taxonomy of threats against satellite firmware. We then conduct an experimental security analysis of three real-world satellite firmware images. We base our analysis on a set of real-world attacker models and find several security-critical vulnerabilities in all analyzed firmware images. The results of our experimental security assessment show that modern in-orbit satellites suffer from different software security vulnerabilities and often a lack of proper access protection mechanisms. They also underline the need to overcome prevailing but obsolete assumptions. To substantiate our observations, we also performed a survey of 19 professional satellite developers to obtain a comprehensive picture of the satellite security landscape
Hammulator: Simulate Now - Exploit Later
Full text linkRowhammer, first considered a reliability issue, turned out to be a significant threat to the security of systems. Hence, several mitigation techniques have been proposed to prevent the exploitation of the Rowhammer effect. Consequently, attackers developed more sophisticated hammering and exploitation techniques to circumvent mitigations. Still, the development and testing of Rowhammer exploits can be a tedious process, taking multiple hours to get the bit flip at the correct location.
In this paper, we propose Hammulator, an open-source rapid-prototyping framework for Rowhammer exploits. We simulate the Rowhammer effect using the gem5 simulator and DRAMsim3 model, with a parameterizable implementation that allows researchers to simulate various types of systems. Hammulator enables faster and more deterministic bit flips, facilitating the development of Rowhammer proof-of-concept exploits and defenses. We evaluate our simulator by reproducing 2 open-source Rowhammer exploits. We also evaluate 2 previously proposed mitigations, PARA and TRR, in our simulator. Additionally, our micro- and macrobenchmarks show that our simulator has a small average overhead in the range of 6.96 % to 10.21 %. Our results show that Hammulator can be used to compare Rowhammer exploits objectively by providing a consistent testing environment. Hammulator and all experiments and evaluations are open source, hoping to ease the research on Rowhammer
Pushed by Accident: A Mixed-Methods Study on Strategies of Handling Secrets in Source Code Repositories
Full text linkVersion control systems for source code, such as Git, are key tools in modern software development. Many developers use services like GitHub or GitLab for collaborative software development. Many software projects include code secrets such as API keys or passwords that need to be managed securely. Previous research and blog posts found that developers struggle with secure code secret management and accidentally leaked code secrets to public Git repositories. Leaking code secrets to the public can have disastrous consequences, such as abusing services and systems or making sensitive user data available to attackers. In a mixed-methods study, we surveyed 109 developers with version control system experience. Additionally, we conducted 14 in-depth semi-structured interviews with developers who experienced secret leakage in the past. 30.3% of our participants encountered code secret leaks in the past. Most of them face several challenges with secret leakage prevention and remediation. Based on our findings, we discuss challenges, such as estimating the risks of leaked secrets, and the needs of developers in remediating and preventing code secret leaks, such as low adoption requirements. We conclude with recommendations for developers and source code platform providers to reduce the risk of secret leakage
Collide+Power: Leaking Inaccessible Data with Software-based Power Side Channels
Full text linkDifferential Power Analysis (DPA) measures single-bit differences between data values used in computer systems by statistical analysis of power traces. In this paper, we show that the mere co-location of data values, e.g., attacker and victim data in the same buffers and caches, leads to power leakage in modern CPUs that depends on a combination of both values, resulting in a novel attack, Collide+Power. We systematically analyze the power leakage of the CPU's memory hierarchy to derive precise leakage models enabling practical end-to-end attacks. These attacks can be conducted in software with any signal related to power consumption, e.g., power consumption interfaces or throttling-induced timing variations. Leakage due to throttling requires 133.3 times more samples than direct power measurements. We develop a novel differential measurement technique amplifying the exploitable leakage by a factor of 8.778 on average, compared to a straightforward DPA approach. We demonstrate that Collide+Power leaks single-bit differences from the CPU's memory hierarchy with fewer than 23000 measurements. Collide+Power varies attacker-controlled data in our end-to-end DPA attacks. We present a Meltdown-style attack, leaking from attacker-chosen memory locations, and a faster MDS-style attack, which leaks 4.82 bit/h. Collide+Power is a generic attack applicable to any modern CPU, arbitrary memory locations, and victim applications and data. However, the Meltdown-style attack is not yet practical, as it is limited by the state of the art of prefetching victim data into the cache, leading to an unrealistic real-world attack runtime with throttling of more than a year for a single bit. Given the different variants and potentially more practical prefetching methods, we consider Collide+Power a relevant threat that is challenging to mitigate
CryptoBap: A Binary Analysis Platform for Cryptographic Protocols
Full text linkWe introduce CryptoBap, a platform to verify weak secrecy and authentication for the (ARMv8 and RISC-V) machine code of cryptographic protocols. We achieve this by first transpiling the binary of protocols into an intermediate representation and then performing a crypto-aware symbolic execution to automatically extract a model of the protocol that represents all its execution paths. Our symbolic execution resolves indirect jumps and supports bounded loops using the loop-summarization technique, which we fully automate. The extracted model is then translated into models amenable to automated verification via ProVerif and CryptoVerif using a third-party toolchain. We prove the soundness of the proposed approach and used CryptoBap to verify multiple case studies ranging from toy examples to real-world protocols, TinySSH, an implementation of SSH, and WireGaurd, a modern VPN protocol
Hardware-Software Codesign for Mitigating Spectre
Full text linkSpectre attacks exploit control- and data-flow (mis)prediction on modern processors to transiently leak program secrets. Comprehensively mitigating Spectre leakage is hard, and doing so while preserving the program’s performance is even harder: no existing Spectre mitigations are widely deployed due to their high overhead or high complexity. We claim that a comprehensive, efficient, and low-complexity mitigation for Spectre attacks requires engaging in software-compiler-hardware co-design. In our talk, we will pitch such a co-designed Spectre mitigation that will be widely deployable at a low cost in security-critical applications. As a first step towards this goal, we have developed Serberus, a comprehensive and proven-correct Spectre mitigation for constant-time code that targets existing hardware. We are currently exploring lightweight hardware support to improve Serberus’ performance in other application domains