Vulnerability Description
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. This vulnerability affects Thunderbird < 52.8, Thunderbird ESR < 52.8, Firefox < 60, and Firefox ESR < 52.8.
CVSS Score
HIGH
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Mozilla | Firefox | < 52.8.0 |
| Mozilla | Thunderbird | < 52.8.0 |
| Mozilla | Thunderbird Esr | < 52.8.0 |
| Microsoft | Windows 10 | - |
References
- http://www.securityfocus.com/bid/104136Third Party AdvisoryVDB Entry
- http://www.securitytracker.com/id/1040896Third Party AdvisoryVDB Entry
- https://bugzilla.mozilla.org/show_bug.cgi?id=1447080Issue TrackingPermissions RequiredThird Party Advisory
- https://www.mozilla.org/security/advisories/mfsa2018-11/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2018-12/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2018-13/Vendor Advisory
- http://www.securityfocus.com/bid/104136Third Party AdvisoryVDB Entry
- http://www.securitytracker.com/id/1040896Third Party AdvisoryVDB Entry
- https://bugzilla.mozilla.org/show_bug.cgi?id=1447080Issue TrackingPermissions RequiredThird Party Advisory
- https://www.mozilla.org/security/advisories/mfsa2018-11/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2018-12/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2018-13/Vendor Advisory
FAQ
What is CVE-2018-5174?
CVE-2018-5174 is a vulnerability with a CVSS score of 7.5 (HIGH). 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 potentiall...
How severe is CVE-2018-5174?
CVE-2018-5174 has been rated HIGH with a CVSS base score of 7.5/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2018-5174?
Check the references section above for vendor advisories and patch information. Affected products include: Mozilla Firefox, Mozilla Thunderbird, Mozilla Thunderbird Esr, Microsoft Windows 10.