#VU8623 Blob and data URLs bypass phishing and malware protection warnings in Mozilla Firefox - CVE-2017-7814

Vulnerability identifier: #VU8623

Vulnerability risk: Medium

CVSSv4.0: 1.2 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2017-7814

CWE-ID: CWE-451

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 phishing and malware protection warnings.

File downloads encoded with blob: and data: URL elements bypassed normal file download checks though the Phishing and Malware Protection feature and its block lists of suspicious sites and files. This would allow malicious sites to lure users into downloading executables that would otherwise be detected as suspicious.

Mitigation
Update to version 56.0.

Vulnerable software versions

Mozilla Firefox: 48.0 - 55.0.3

---

External links
https://www.mozilla.org/en-US/security/advisories/mfsa2017-21/

---

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.