MitM-attack in Mozilla Firefox ESR

1) Resource management error

EUVDB-ID: #VU49018

Risk: Low

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

CVE-ID: CVE-2020-26976

CWE-ID: CWE-399 - Resource Management Errors

Exploit availability: No

Description

The vulnerability allows a remote attacker to gain access to sensitive information.

The vulnerability exists due to improper management of internal resources within the application, when processing embedded elements with https/http protocols. When a HTTPS pages was embedded in a HTTP page, and there was a service worker registered for the former, the service worker could have intercepted the request for the secure page despite the iframe not being a secure context due to the (insecure) framing.

Mitigation

Install update from vendor's website

Vulnerable software versions

Firefox ESR: 60.0 - 78.6.1

CPE2.3

• cpe:2.3:a:mozilla:firefox_esr:60.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox_esr:60.0.1:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox_esr:60.0.2:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox_esr:60.1.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox_esr:60.2.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox_esr:60.2.1:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox_esr:60.2.2:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox_esr:*:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox_esr:60.5.0:*:*:*:*:*:*:*

External links

https://www.mozilla.org/en-US/security/advisories/mfsa2021-04/

Q & A

Can this vulnerability be exploited remotely?

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

How the attacker can exploit this vulnerability?

The attacker would have to trick the victim to visit a specially crafted website.

Is there known malware, which exploits this vulnerability?

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