Mozilla Firefox ESR < 91.3

critical Nessus Plugin ID 154817

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Synopsis

A web browser installed on the remote Windows host is affected by multiple vulnerabilities.

Description

The version of Firefox ESR installed on the remote Windows host is prior to 91.3. It is, therefore, affected by multiple vulnerabilities as referenced in the mfsa2021-49 advisory.

- The iframe sandbox rules were not correctly applied to XSLT stylesheets, allowing an iframe to bypass restrictions such as executing scripts or navigating the top-level frame. (CVE-2021-38503)

- When interacting with an HTML input element's file picker dialog with <code>webkitdirectory</code> set, a use-after-free could have resulted, leading to memory corruption and a potentially exploitable crash.
(CVE-2021-38504)

- Microsoft introduced a new feature in Windows 10 known as Cloud Clipboard which, if enabled, will record data copied to the clipboard to the cloud, and make it available on other computers in certain scenarios.
Applications that wish to prevent copied data from being recorded in Cloud History must use specific clipboard formats; and Firefox before versions 94 and ESR 91.3 did not implement them. This could have caused sensitive data to be recorded to a user's Microsoft account. This bug only affects Firefox for Windows 10+ with Cloud Clipboard enabled. Other operating systems are unaffected. (CVE-2021-38505)

- Through a series of navigations, Firefox could have entered fullscreen mode without notification or warning to the user. This could lead to spoofing attacks on the browser UI including phishing.
(CVE-2021-38506)

- The Opportunistic Encryption feature of HTTP2 (RFC 8164) allows a connection to be transparently upgraded to TLS while retaining the visual properties of an HTTP connection, including being same-origin with unencrypted connections on port 80. However, if a second encrypted port on the same IP address (e.g. port 8443) did not opt-in to opportunistic encryption; a network attacker could forward a connection from the browser to port 443 to port 8443, causing the browser to treat the content of port 8443 as same-origin with HTTP. This was resolved by disabling the Opportunistic Encryption feature, which had low usage.
(CVE-2021-38507)

- By displaying a form validity message in the correct location at the same time as a permission prompt (such as for geolocation), the validity message could have obscured the prompt, resulting in the user potentially being tricked into granting the permission. (CVE-2021-38508)

- Due to an unusual sequence of attacker-controlled events, a Javascript <code>alert()</code> dialog with arbitrary (although unstyled) contents could be displayed over top an uncontrolled webpage of the attacker's choosing. (CVE-2021-38509)

- The executable file warning was not presented when downloading .inetloc files, which, due to a flaw in Mac OS, can run commands on a user's computer. Note: This issue only affected Mac OS operating systems. Other operating systems are unaffected. (CVE-2021-38510)

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

Solution

Upgrade to Mozilla Firefox ESR version 91.3 or later.

Plugin Details

Severity: Critical

ID: 154817

File Name: mozilla_firefox_91_3_esr.nasl

Version: 1.7

Type: local

Agent: windows

Family: Windows

Published: 11/2/2021

Updated: 3/17/2022

Supported Sensors: Frictionless Assessment Agent, Frictionless Assessment AWS, Frictionless Assessment Azure, Nessus Agent, Nessus

Risk Information

VPR

Risk Factor: High

Score: 7.3

CVSS v2

Risk Factor: High

Base Score: 7.5

Temporal Score: 5.5

Vector: CVSS2#AV:N/AC:L/Au:N/C:P/I:P/A:P

CVSS Score Source: CVE-2021-38503

CVSS v3

Risk Factor: Critical

Base Score: 10

Temporal Score: 8.7

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C

Vulnerability Information

CPE: cpe:/a:mozilla:firefox_esr

Required KB Items: Mozilla/Firefox/Version

Exploit Ease: No known exploits are available

Patch Publication Date: 11/2/2021

Vulnerability Publication Date: 11/2/2021

Reference Information

CVE: CVE-2021-38503, CVE-2021-38504, CVE-2021-38505, CVE-2021-38506, CVE-2021-38507, CVE-2021-38508, CVE-2021-38509, CVE-2021-38510

IAVA: 2021-A-0527-S

Detections

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