Bug 1576274 (CVE-2018-5174)

Summary:	CVE-2018-5174 Mozilla: Windows Defender SmartScreen UI runs with less secure behavior for downloaded files in Windows 10 April 2018 Update
Product:	[Other] Security Response	Reporter:	Doran Moppert <dmoppert>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED NOTABUG	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	cschalle, gecko-bugs-nobody, jhorak, security-response-team, stransky
Target Milestone:	---	Keywords:	Security
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Hardware:	All
OS:	Linux
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Last Closed:	2019-06-10 10:22:14 UTC	Type:	---
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oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
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Bug Depends On:
Bug Blocks:	1573375

Description Doran Moppert 2018-05-09 07:15:47 UTC

In the Windows 10 April 2018 Update, Windows Defender SmartScreen honors the `SEE_MASK_FLAG_NO_UI` flag associated with downloaded files and will not show any UI. Files that are unknown and potentially dangerous will be allowed to run because SmartScreen will not prompt the user for a decision, and if the user is offline all files will be allowed to be opened because Windows won’t prompt the user to ask what to do. Firefox incorrectly sets this flag when downloading files, leading to less secure behavior from SmartScreen. 

*Note: this issue only affects Windows 10 users running the April 2018 update or later. It does not affect other Windows users or other operating systems.*



External Reference:

https://www.mozilla.org/en-US/security/advisories/mfsa2018-11/#CVE-2018-5174

Comment 1 Doran Moppert 2018-05-09 07:15:49 UTC

Acknowledgments:

Name: the Mozilla project
Upstream: Jimmy