Abstract
While private browsing is a standard feature, its implementation has been inconsistent among the major browsers. More seriously, it often fails to provide the adequate or even the intended privacy protection. For example, as shown in prior research, browser extensions and addons often undermine the goals of private browsing. In this paper, we first present our systematic study of private browsing. We developed a technical approach to identify browser traces left behind by a private browsing session, and showed that Chrome and Firefox do not correctly clear some of these traces. We analyzed the source code of these browsers and discovered that the current implementation approach is to decide the behaviors of a browser based on the current browsing mode (i.e., private or public); but such decision points are scattered throughout the code base. This implementation approach is very problematic because developers are prone to make mistakes given the complexities of browser components (including extensions and add-ons). Based on this observation, we propose a new and general approach to implement private browsing. The main idea is to overlay the actual filesystem with a sandbox filesystem when the browser is in private browsing mode, so that no unintended leakage is allowed and no persistent modification is stored. This approach requires no change to browsers and the OS kernel because the layered sandbox filesystem is implemented by interposing system calls. We have implemented a prototype system called UCOGNITO on Linux. Our evaluations show that UCOGNITO, when applied to Chrome and Firefox, stops all known privacy leaks identified by prior work and our current study. More importantly, UCOGNITO incurs only negligible performance overhead: e.g., 0%-2.5% in benchmarks for standard JavaScript and webpage loading.
Original language | English (US) |
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Title of host publication | CCS 2015 - Proceedings of the 22nd ACM SIGSAC Conference on Computer and Communications Security |
Publisher | Association for Computing Machinery |
Pages | 438-449 |
Number of pages | 12 |
ISBN (Electronic) | 9781450338325 |
DOIs | |
State | Published - Oct 12 2015 |
Event | 22nd ACM SIGSAC Conference on Computer and Communications Security, CCS 2015 - Denver, United States Duration: Oct 12 2015 → Oct 16 2015 |
Publication series
Name | Proceedings of the ACM Conference on Computer and Communications Security |
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Volume | 2015-October |
ISSN (Print) | 1543-7221 |
Conference
Conference | 22nd ACM SIGSAC Conference on Computer and Communications Security, CCS 2015 |
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Country/Territory | United States |
City | Denver |
Period | 10/12/15 → 10/16/15 |
Funding
We thank Frank Wang and the anonymous reviewers for their helpful feedback, as well as our operations staff for their proofreading efforts. This research was supported by the NSF award CNS-1017265, CNS-0831300, CNS-1149051 and DGE-1500084, by the ONR under grant N000140911042 and N000141512162, by the DHS under contract N66001-12-C-0133, by the United States Air Force under contract FA8650-10-C-7025, by the DARPA Transparent Computing program under contract DARPA-15-15-TC-FP-006, and by the ETRI MSIP/IITP[B0101-15-0644]. Any opinions, findings, conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the NSF, ONR, DHS, United States Air Force or DARPA.
Keywords
- Browser implementation
- Filesystem sandbox
- Private browsing
ASJC Scopus subject areas
- Software
- Computer Networks and Communications