SB2021110325 - Ubuntu update for firefox

Description

This security bulletin contains information about 6 secuirty vulnerabilities.

1) Security features bypass (CVE-ID: CVE-2021-38503)

The vulnerability allows a remote attacker to bypass implemented security restrictions.

The vulnerability exists due to the iframe sandbox rules were not correctly applied to XSLT stylesheets. A remote attacker can load use an iframe to bypass restrictions such as executing scripts or navigating the top-level frame.

2) Use-after-free (CVE-ID: CVE-2021-38504)

The vulnerability allows a remote attacker to compromise vulnerable system.

The vulnerability exists due to a use-after-free error when interacting with an HTML input element's file picker dialog with webkitdirectory set. A remote attacker can trick the victim to open a specially crafted website, trigger a use-after-free error and execute arbitrary code on the system.

Successful exploitation of the vulnerability may allow an attacker to compromise vulnerable system.

3) Insufficient UI Warning of Dangerous Operations (CVE-ID: CVE-2021-38506)

The vulnerability allows a remote attacker to perform spoofing attacks.

The vulnerability exists due to Firefox could have entered fullscreen mode without notification or warning to the user. A remote attacker can perform spoofing attacks on the browser UI.

4) Security features bypass (CVE-ID: CVE-2021-38507)

The vulnerability allows a remote attacker to bypass implemented security restrictions.

The vulnerability exists in the Opportunistic Encryption feature of HTTP2, which 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 from port 443 to port 8443, causing the browser to treat the content of port 8443 as same-origin with HTTP. As a result, a remote attacker can bypass Same-Origin-Policy on services hosted on other ports.

5) Improper Restriction of Rendered UI Layers or Frames (CVE-ID: CVE-2021-38508)

The vulnerability allows a remote attacker to perform spoofing attack.

The vulnerability exists due to Firefox displays the 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.

6) Improper Restriction of Rendered UI Layers or Frames (CVE-ID: CVE-2021-38509)

The vulnerability allows a remote attacker to perform spoofing attack.

The vulnerability exists due to incorrect processing of an unusual sequence of attacker-controlled events. A remote attacker can display a Javascript alert() dialog with arbitrary (although unstyled) contents over top of arbitrary webpage of the attacker's choosing.

Remediation

Install update from vendor's website.

References

• https://ubuntu.com/security/notices/USN-5131-1