Vulnerabilities Firefox Thunderbird Allow Code Execution

Fortify Security Team
Mar 24, 2021

Multiple vulnerabilities have been discovered in Mozilla Firefox, Firefox Extended Support Release (ESR) and Mozilla Thunderbird, the most severe of which could allow for arbitrary code execution. Mozilla Firefox is a web browser used to access the Internet. Mozilla Firefox ESR is a version of the web browser intended to be deployed in large organizations. Mozilla Thunderbird is an email client. Successful exploitation of these vulnerabilities could allow for arbitrary code execution. Depending on the privileges associated with the user an attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. Users whose accounts are configured to have fewer user rights on the system could be less impacted than those who operate with administrative user rights.

THREAT INTELLIGENCE: There are currently no reports of these vulnerabilities being exploited in the wild.

SYSTEMS AFFECTED:

  • Mozilla Firefox versions prior to 87
  • Firefox ESR versions prior to 78.9
  • Mozilla Thunderbird versions prior to 78.9

RISK:
Government:

  • Large and medium government entities: High
  • Small government entities: High

Businesses:

  • Large and medium business entities: High
  • Small business entities: High

Home users: Low

TECHNICAL SUMMARY:

Multiple vulnerabilities have been discovered in Mozilla Firefox, and Firefox Extended Support Release (ESR), and Mozilla Thunderbird, the most severe of which could allow for arbitrary code execution. Details of these vulnerabilities are as follows:

  • A texture upload of a Pixel Buffer Object could have confused the WebGL code to skip binding the buffer used to unpack it, resulting in memory corruption and a potentially exploitable information leak or crash (CVE-2021-23981).
  • Using techniques that built on the slipstream research, a malicious webpage could have scanned both an internal network’s hosts as well as services running on the user’s local machine utilizing WebRTC connections (CVE-2021-23982).
  • By causing a transition on a parent node by removing a CSS rule, an invalid property for a marker could have been applied, resulting in memory corruption and a potentially exploitable crash (CVE-2021-23983).
  • A malicious extension could have opened a popup window lacking an address bar. The title of the popup lacking an address bar should not be fully controllable, but in this situation was. This could have been used to spoof a website and attempt to trick the user into providing credentials (CVE-2021-23984).
  • If an attacker is able to alter specific about:config values (for example malware running on the user’s computer), the Devtools remote debugging feature could have been enabled in a way that was unnoticeable to the user. This would have allowed a remote attacker (able to make a direct network connection to the victim) to monitor the user’s browsing activity and (plaintext) network traffic. This was addressed by providing a visual cue when Devtools has an open network socket (CVE-2021-23985).
  • A malicious extension with the ‘search’ permission could have installed a new search engine whose favicon referenced a cross-origin URL. The response to this cross-origin request could have been read by the extension, allowing a same-origin policy bypass by the extension, which should not have cross-origin permissions. This cross-origin request was made without cookies, so the sensitive information disclosed by the violation was limited to local-network resources or resources that perform IP-based authentication (CVE-2021-23986).
  • Mozilla developers and community members Matthew Gregan, Tyson Smith, Julien Wajsberg, and Alexis Beingessner reported memory safety bugs present in Firefox 86 and Firefox ESR 78.8. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code (CVE-2021-23987).
  • Mozilla developers Tyson Smith and Christian Holler reported memory safety bugs present in Firefox 86. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code (CVE-2021-23988)

Successful exploitation of these vulnerabilities could allow for arbitrary code execution. Depending on the privileges associated with the user an attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. Users whose accounts are configured to have fewer user rights on the system could be less impacted than those who operate with administrative user rights.

RECOMMENDATIONS:

We recommend the following actions be taken:

  • Apply appropriate updates provided by Mozilla to vulnerable systems immediately after appropriate testing.
  • Run all software as a non-privileged user (one without administrative privileges) to diminish the effects of a successful attack.
  • Remind users not to visit un-trusted websites or follow links provided by unknown or un-trusted sources.
  • Inform and educate users regarding the threats posed by hypertext links contained in emails or attachments especially from un-trusted sources.
  • Apply the Principle of Least Privilege to all systems and services.

REFERENCES:
Mozilla:
https://www.mozilla.org/en-US/security/advisories/mfsa2021-10/
https://www.mozilla.org/en-US/security/advisories/mfsa2021-11/
https://www.mozilla.org/en-US/security/advisories/mfsa2021-12/

CVE:
https://cve.mitre.org/cgi-bin/cvekey.cgi?keyword=CVE-2021-23981
https://cve.mitre.org/cgi-bin/cvekey.cgi?keyword=CVE-2021-23982
https://cve.mitre.org/cgi-bin/cvekey.cgi?keyword=CVE-2021-23983
https://cve.mitre.org/cgi-bin/cvekey.cgi?keyword=CVE-2021-23984
https://cve.mitre.org/cgi-bin/cvekey.cgi?keyword=CVE-2021-23985
https://cve.mitre.org/cgi-bin/cvekey.cgi?keyword=CVE-2021-23986
https://cve.mitre.org/cgi-bin/cvekey.cgi?keyword=CVE-2021-23987
https://cve.mitre.org/cgi-bin/cvekey.cgi?keyword=CVE-2021-23988

Recent Posts

Palo Alto PAN-OS Could Allow for Arbitrary Code Execution

A vulnerability has been discovered in Palo Alto PAN-OS that could allow for arbitrary code execution. PAN-OS is the software that runs on all Palo Alto Network firewalls. Successful exploitation of this vulnerability could allow for arbitrary code execution....

November 2021 – Patch Tuesday

Multiple vulnerabilities have been discovered in Microsoft products, the most severe of which could allow for arbitrary code execution in the context of the logged on user. Depending on the privileges associated with the user, an attacker could then install programs;...

Mozilla Firefox Could Allow for Arbitrary Code Execution

Multiple vulnerabilities have been discovered in Mozilla Firefox and Firefox Extended Support Release (ESR), the most severe of which could allow for arbitrary code execution. Mozilla Firefox is a web browser used to access the Internet. Mozilla Firefox ESR is a...

Google Chrome Could Allow for Arbitrary Code Execution

Multiple vulnerabilities have been discovered in Google Chrome, the most severe of which could allow for arbitrary code execution. Google Chrome is a web browser used to access the Internet. Successful exploitation of the most severe of these vulnerabilities could...

Cisco ASA and Firepower Threat Defense Allow for Security Bypass

A vulnerability has been discovered in Cisco Adaptive Security Appliance and Firepower Threat Defense, which could allow attackers to bypass security mechanisms on the system. Successful exploitation of this vulnerability could allow an unauthenticated remote attacker...

Apple Products Vulnerable to Arbitrary Code Execution

Multiple vulnerabilities have been discovered in Apple Products, the most severe of which could allow for arbitrary code execution. iOS is a mobile operating system for mobile devices, including the iPhone, iPad, and iPod touch. iPadOS is the successor to iOS 12 and...