Vulnerability identifier: #VU9327

Vulnerability risk: Low

CVSSv3.1: 4.1 [CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2017-7840

CWE-ID: CWE-20

Exploitation vector: Network

Exploit availability: No

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

Vendor: Mozilla

Description

The vulnerability allows a remote attacker to bypass Self-XSS prevention mechanism.

JavaScript can be injected into an exported bookmarks file by placing JavaScript code into user-supplied tags in saved bookmarks. If the resulting exported HTML file is later opened in a browser this JavaScript will be executed. This could be used in social engineering and self-cross-site-scripting (self-XSS) attacks if users were convinced to add malicious tags to bookmarks, export them, and then open the resulting file.

Mitigation
Update to version Firefox 57.

Vulnerable software versions

Mozilla Firefox: 53.0 - 56.0.1

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External links
http://www.mozilla.org/en-US/security/advisories/mfsa2017-24/

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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.