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Multiple Vulnerabilities in Mozilla Firefox and Thunderbird Could Allow for Arbitrary Code Execution

MS-ISAC ADVISORY NUMBER:

2021-051

DATE(S) ISSUED:

04/20/2021

OVERVIEW:

Multiple vulnerabilities have been discovered in Mozilla Firefox/Firefox ESR/Thunderbird, the most severe of which could allow for arbitrary code execution. Mozilla Firefox is a web browser that is 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 87.0
  • Mozilla Firefox ESR versions prior to 78.9
  • Mozilla Thunderbird versions prior to 78.7

RISK:

Government:
  • Large and medium government entities: HIGH
  • Small government entities: MEDIUM
Businesses:
  • Large and medium business entities: HIGH
  • Small business entities: MEDIUM
Home Users:
LOW

TECHNICAL SUMMARY:

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

  • Internal network hosts probing vulnerability exist when slipstream techniques and malicious webpage are combined. (CVE-2021-23961)
  • A memory corruption and out of bounds write vulnerability exist when WebGL framebuffer is not initialized early enough. (CVE-2021-23994)
  • An arbitrary code execution vulnerability exist when Responsive Design Mode is enabled. (CVE-2021-23995)
  • Content outside webpage viewport vulnerability exist when 3D CSS and Javascript are combined. (CVE-2021-23996)
  • Arbitrary code execution vulnerability exist when using font cache. (CVE-2021-23997)
  • A spoofing vulnerability exist when an HTTP page could have inherited a secure lock icon from an HTTPS page. (CVE-2021-23998)
  • A privilege-escalation vulnerability exist when a Blob url is loaded through some unusual user interaction or by privileged user. (CVE-2021-23999)
  • An information disclosure vulnerability exist when requestPointerLock() is applied to the incorrect tab. (CVE-2021-24000)
  • Session history manipulation vulnerability exist when infrastructure is not restricted to testing-only configurations. (CVE-2021-24001)
  • A command-execution vulnerability exist when clicked on a FTP url containing encoded newline characters (%0A and %0D). (CVE-2021-24002)
  • HTML injection vulnerability exist with no Content Security Policy (CVE-2021-29944)
  • A denial-of-service vulnerability exist when WebAssembly JIT miscalculates the size of a return type. (CVE-2021-29945)
  • A security-bypass vulnerability exist when it bypasses port blocking restrictions when used in the Alt-Svc header. (CVE-2021-29946)
  • Memory corruption vulnerability (CVE-2021-29947)
  • A race condition vulnerability exist when reading from disk while verifying signatures (CVE-2021-29948)

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 patches 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:

Information Hub : Advisories


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