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Desktop operating systems, including macOS, Windows 10, and Linux, are adopting the application-based security model pervasive in mobile platforms. In Linux, this transition is part of the movement towards two distribution-independent application platforms: Flatpak and Snap. This paper provides the first analysis of sandbox policies defined for Flatpak and Snap applications, covering 283 applications contained in both platforms. First, we find that 90.1% of Snaps and 58.3% of Flatpak applications studied are contained by tamperproof sandboxes. Further, we find evidence that package maintainers actively attempt to define least-privilege application policies. However, defining policy is difficult and error-prone. When studying the set of matching applications that appear in both Flatpak and Snap app stores, we frequently found policy mismatches: e.g., the Flatpak version has a broad privilege (e.g., file access) that the Snap version does not, or vice versa. This work provides confidence that Flatpak and Snap improve Linux platform security while highlighting opportunities for improvement.
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μSCOPE: A Methodology for Analyzing Least-Privilege Compartmentalization in Large Software Artifacts
By prioritizing simplicity and portability, least-privilege engineering has been an afterthought in OS design, resulting in monolithic kernels where any exploit leads to total compromise. μSCOPE (“microscope”) addresses this problem by automatically identifying opportunities for least-privilege separation. μSCOPE replaces expert-driven, semi-automated analysis with a general methodology for exploring a continuum of security vs. performance design points by adopting a quantitative and systematic approach to privilege analysis. We apply the μSCOPE methodology to the Linux kernel by (1) instrumenting the entire kernel to gain comprehensive, fine-grained memory access and call activity; (2) mapping these accesses to semantic information; and (3) conducting separability analysis on the kernel using both quantitative privilege and overhead metrics. We discover opportunities for orders of magnitude privilege reduction while predicting relatively low overheads—at 15% mediation overhead, overprivilege in Linux can be reduced up to 99.8%—suggesting fine-grained privilege separation is feasible and laying the groundwork for accelerating real privilege separation.
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- PAR ID:
- 10319345
- Date Published:
- Journal Name:
- 24th International Symposium on Research in Attacks, Intrusions and Defenses
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Conference Paper:
- https://doi.org/10.1145/3471621.3471839
