With millions of apps available to users, the mobile app market is rapidly becoming very crowded. Given the intense competition, the time to market is a critical factor for the success and profitability of an app. In order to shorten the development cycle, developers often focus their efforts on the unique features and workflows of their apps and rely on third-party Open Source Software (OSS) for the common features. Unfortunately, despite their benefits, careless use of OSS can introduce significant legal and security risks, which if ignored can not only jeopardize security and privacy of end users, but can also cause app developers high financial loss. However, tracking OSS components, their versions, and interdependencies can be very tedious and error-prone, particularly if an OSS is imported with little to no knowledge of its provenance. We therefore propose OSSPolice, a scalable and fully-automated tool for mobile app developers to quickly analyze their apps and identify free software license violations as well as usage of known vulnerable versions of OSS. OSSPolice introduces a novel hierarchical indexing scheme to achieve both high scalability and accuracy, and is capable of efficiently comparing similarities of app binaries against a database of hundreds of thousands of OSS sources (billions of lines of code). We populated OSSPolice with 60K C/C++ and 77K Java OSS sources and analyzed 1.6M free Google Play Store apps. Our results show that 1) over 40K apps potentially violate GPL/AGPL licensing terms, and 2) over 100K of apps use known vulnerable versions of OSS. Further analysis shows that developers violate GPL/AGPL licensing terms due to lack of alternatives, and use vulnerable versions of OSS despite efforts from companies like Google to improve app security. OSSPolice is available on GitHub.

The openness and extensibility of Android have made it a popular platform for mobile devices and a strong candidate to drive the Internet-of-Things. Unfortunately, these properties also leave Android vulnerable, attracting attacks for profit or fun. To mitigate these threats, numerous issue-specific solutions have been proposed. With the increasing number and complexity of security problems and solutions, we believe this is the right moment to step back and systematically re-evaluate the Android security architecture and security practices in the ecosystem. We organize the most recent security research on the Android platform into two categories: the software stack and the ecosystem. For each category, we provide a comprehensive narrative of the problem space, highlight the limitations of the proposed solutions, and identify open problems for future research. Based on our collection of knowledge, we envision a blueprint for engineering a secure, next-generation Android ecosystem.

Mobile application developers rely heavily on opensource software (OSS) to offload common functionalities such as the implementation of protocols and media format playback. Over the past years, several vulnerabilities have been found in popular open-source libraries like OpenSSL and FFmpeg. Mobile applications that include such libraries inherit these flaws, which make them vulnerable. Fortunately, the open-source community is responsive and patches are made available within days. However, mobile application developers are often left unaware of these flaws. The App Security Improvement Program (ASIP) is a commendable effort by Google to notify application developers of these flaws, but recent work has shown that many developers do not act on this information. Our work addresses vulnerable mobile applications through automatic binary patching from source patches provided by the OSS maintainers and without involving the developers. We propose novel techniques to overcome difficult challenges like patching feasibility analysis, source-code-to-binary-code matching, and in-memory patching. Our technique uses a novel variabilityaware approach, which we implement as OSSPATCHER. We evaluated OSSPATCHER with 39 OSS and a collection of 1,000 Android applications using their vulnerable versions. OSSPATCHER generated 675 function-level patches that fixed the affected mobile applications without breaking their binary code. Further, we evaluated 10 vulnerabilities in popular apps such as Chrome with public exploits, which OSSPATCHER was able to mitigate and thwart their exploitation.

organizations that rely on open-source interpreted programming languages for different internal and external applications. Attackers can infiltrate well-defended organization by simply subverting the software supply chain of registries. For example, eslint-scope [4], a package with millions of weekly downloads in Npm, was compromised to steal credentials from developers. Similarly, rest-client [5], which has over one hundred million downloads in RubyGems, was compromised to leave a Remote-Code-Execution (RCE) backdoor on web servers. These attacks demonstrate how miscreants can covertly gain access to a wide-range of organizations by carrying out a software supply chain attack. Security researchers [7] are aware of these attacks and have proposed several solutions to address the rise of malicious software in registries. Zimmermann et al. [8] systematically studied 609 known security issues and revealed a large attack surface in the Npm ecosystem. BreakApp [9], on the other hand, isolates untrusted packages, which addresses credential theft and prevents access to sensitive data, but does not stop cryptocurrency mining or backdoors. Additionally, many solutions [10]-[12] assume inherent trust and focus on finding bugs in packages rather than malicious packages. To make matters worse, some attacks are very sinister and use social engineering techniques [13], [14] to disguise themselves by first publishing a "useful" package, then waiting until it is used by their target to update it and include malicious payloads. Although, many security researchers are actively investigating attacks on registries and proposing solutions, these approaches seem to be ad-hoc and one-off solutions. A better approach is to understand the extent of the software supply chain abuse and how miscreants are taking advantage of them. The approach must be grounded to allow an objective comparison between the different registry ecosystem. To this end, we propose a framework that highlights key functionality, security mechanisms, stakeholders, and remediation techniques to comparatively analyze different registry ecosystems. We use our framework to look at what features registries provide, what security principles are enforced, how is trust delegated between different parties, and what remediation and contingency plans registries have in place for post-attack. We leverage our findings to provide practical action items that registry maintainers can enforce using pre-existing tools and security principles that will improve the security of the overall package management ecosystem. Using well-known program analysis techniques, we build MALOSS, a custom pipeline tailored for interpreted languages that we use to empirically study the security of package managers. We make this pipeline Abstract-Package managers have become a vital part of the modern software development process. They allow developers to reuse third-party code, share their own code, minimize their codebase, and simplify the build process. However, recent reports showed that package manag...

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With the fast development of Internet, the size of routing tables in the backbone routers keeps a rapid growth in recent years. An effective solution to control the memory occupation of the ever-increased huge routing table is the Forwarding Information Base (FIB) compression. Existing optimal FIB compression algorithm ORTC suffers from high computational complexity and poor update performance, due to the loss of essential structure information during its compression process. To address this problem, we present two sub-optimal FIB compression algorithms --EAR-fast and EAR-slow, respectively, based on our proposed Election and Representative (EAR) algorithm which is an optimal FIB compression algorithm. The two suboptimal algorithms preserve the structure information, and support fast incremental updates while reducing computational complexity. Experiments on an 18-month real data set show that compared with ORTC, the proposed EAR-fast algorithm requires only 9.8% compression time and 37.7% memory space, but supports faster update while prolonging the recompression interval remarkably. All these performance advantages come at a cost of merely a 1.5% loss in compression ratio compared with the theoretical optimal ratio.

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Over 55% of the world's websites run on Content Management Systems (CMS). Unfortunately, this huge user population has made CMS-based websites a high-profile target for hackers. Worse still, the vast majority of the website hosting industry has shifted to a "backup and restore" model of security, which relies on error-prone AV scanners to prompt users to roll back to a pre-infection nightly snapshot. This research had the opportunity to study these nightly backups for over 300,000 unique production websites. In doing so, we measured the attack landscape of CMS-based websites and assessed the effectiveness of the backup and restore protection scheme. To our surprise, we found that the evolution of tens of thousands of attacks exhibited clear long-lived multi-stage attack patterns. We now propose TARDIS, an automated provenance inference technique, which enables the investigation and remediation of CMS-targeting attacks based on only the nightly backups already being collected by website hosting companies. With the help of our industry collaborator, we applied TARDIS to the nightly backups of those 300K websites and found 20,591 attacks which lasted from 6 to 1,694 days, some of which were still yet to be detected.