Vulnerability identifier: #VU46016

Vulnerability risk: Medium

CVSSv3.1: 6.5 [CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2020-15664

CWE-ID: CWE-399

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Mozilla Firefox
Client/Desktop applications / Web browsers
Firefox ESR
Client/Desktop applications / Web browsers

Vendor: Mozilla

Description

The vulnerability allows a remote attacker to bypass certain security restrictions.

The vulnerability exists due to the way Firefox handles prompts. By holding a reference to the eval() function from an about:blank window, a malicious webpage could have gained access to the InstallTrigger object which would allow them to prompt the user to install an extension. Combined with user confusion, this could result in an unintended or malicious extension being installed.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Mozilla Firefox: 60.0 - 79.0

Firefox ESR: 60.0 - 60.9.0, 68.0 - 68.11.0, 78.0 - 78.1.0

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External links
http://www.mozilla.org/en-US/security/advisories/mfsa2020-38/
http://www.mozilla.org/en-US/security/advisories/mfsa2020-37/
http://www.mozilla.org/en-US/security/advisories/mfsa2020-36/

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.