Vulnerability identifier: #VU17264

Vulnerability risk: Low

CVSSv3.1: 2.7 [CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:N/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2018-18506

CWE-ID: CWE-200

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 gain access to sensitive information.

The vulnerability exists due to an error in proxy support implementation. When proxy auto-detection is enabled, if a web server serves a Proxy Auto-Configuration (PAC) file or if a PAC file is loaded locally, this PAC file can specify that requests to the localhost are to be sent through the proxy to another server. This behavior is disallowed by default when a proxy is manually configured, but when enabled could allow for attacks on services and tools that bind to the localhost for networked behavior if they are accessed through browsing.

A remote attacker can trick the victim to visit a specially crafted website and gain unauthorized access to services or resources, exposed on user's system.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Mozilla Firefox: 61.0 - 64.0.2

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External links
http://www.mozilla.org/en-US/security/advisories/mfsa2019-01/

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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.