TLP:CLEAR
MS-ISAC CYBERSECURITY ADVISORY

MS-ISAC ADVISORY NUMBER:
2022-139

DATE(S) ISSUED:
12/14/2022

SUBJECT:
A Vulnerability in Fortinet's FortiOS Could Allow for Arbitrary Code Execution

OVERVIEW:
A vulnerability has been discovered in Fortinet's FortiOS, which could allow for arbitrary code Execution. FortiOS is the Fortinet’s proprietary Operation System which is utilized across multiple product lines. 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:
Fortinet is aware of instances where there is an exploitation against the vulnerability.

SYSTEMS AFFECTED:

  • FortiOS version 7.2.0 through 7.2.2
  • FortiOS version 7.0.0 through 7.0.8
  • FortiOS version 6.4.0 through 6.4.10
  • FortiOS version 6.2.0 through 6.2.11
  • FortiOS-6K7K version 7.0.0 through 7.0.7
  • FortiOS-6K7K version 6.4.0 through 6.4.9
  • FortiOS-6K7K version 6.2.0 through 6.2.11
  • FortiOS-6K7K version 6.0.0 through 6.0.14

 

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

DESCRIPTION:
A vulnerability has been discovered in Fortinet's FortiOS which could allow for arbitrary code execution. Details of this vulnerability are as follows: 

TacticInitial Access  (TA0001):

Technique: Exploit Public Facing Application (T1190):

  • CVE-2022-42475 - A heap-based buffer overflow vulnerability [CWE-122] in FortiOS SSL-VPN may allow a remote unauthenticated attacker to execute arbitrary code or commands via specifically crafted requests.

Successful exploitation of this vulnerability 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; 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.

ACTIONS:
We recommend the following actions be taken:

  • Apply the stable channel update provided by Fortinet to vulnerable systems immediately after appropriate testing. (M1051: Update Software)
    • Safeguard 7.1 : Establish and Maintain a Vulnerability Management Process: Establish and maintain a documented vulnerability management process for enterprise assets. Review and update documentation annually, or when significant enterprise changes occur that could impact this Safeguard.
    • Safeguard 7.2 : Establish and Maintain a Remediation Process: Establish and maintain a risk-based remediation strategy documented in a remediation process, with monthly, or more frequent, reviews.
    • Safeguard 7.4: Perform Automated Application Patch Management: Perform application updates on enterprise assets through automated patch management on a monthly, or more frequent, basis.
    • Safeguard 7.6 : Perform Automated Vulnerability Scans of Externally-Exposed Enterprise Assets: Perform automated vulnerability scans of externally-exposed enterprise assets using a SCAP-compliant vulnerability scanning tool. Perform scans on a monthly, or more frequent, basis.
    • Safeguard 7.7 : Remediate Detected Vulnerabilities: Remediate detected vulnerabilities in software through processes and tooling on a monthly, or more frequent, basis, based on the remediation process.
    • Safeguard 12.1 Ensure Network Infrastructure is Up-to-Date: Ensure network infrastructure is kept up-to-date. Example implementations include running the latest stable release of software and/or using currently supported network-as-a-service (NaaS) offerings. Review software versions monthly, or more frequently, to verify software support.
    • Safeguard 18.1 : Establish and Maintain a Penetration Testing Program: Establish and maintain a penetration testing program appropriate to the size, complexity, and maturity of the enterprise. Penetration testing program characteristics include scope, such as network, web application, Application Programming Interface (API), hosted services, and physical premise controls; frequency; limitations, such as acceptable hours, and excluded attack types; point of contact information; remediation, such as how findings will be routed internally; and retrospective requirements.
    • Safeguard 18.2 : Perform Periodic External Penetration Tests: Perform periodic external penetration tests based on program requirements, no less than annually. External penetration testing must include enterprise and environmental reconnaissance to detect exploitable information. Penetration testing requires specialized skills and experience and must be conducted through a qualified party. The testing may be clear box or opaque box.
    • Safeguard 18.3 : Remediate Penetration Test Findings: Remediate penetration test findings based on the enterprise’s policy for remediation scope and prioritization.
  • Apply the Principle of Least Privilege to all systems and services. Run all software as a non-privileged user (one without administrative privileges) to diminish the effects of a successful attack. (M1026: Privileged Account Management)
    • Safeguard 4.7: Manage Default Accounts on Enterprise Assets and Software: Manage default accounts on enterprise assets and software, such as root, administrator, and other pre-configured vendor accounts. Example implementations can include: disabling default accounts or making them unusable.
    • Safeguard 5.3 : Disable Dormant Accounts: Delete or disable any dormant accounts after a period of 45 days of inactivity, where supported.
    • Safeguard 5.5: Establish and Maintain an Inventory of Service Accounts: Establish and maintain an inventory of service accounts. The inventory, at a minimum, must contain department owner, review date, and purpose. Perform service account reviews to validate that all active accounts are authorized, on a recurring schedule at a minimum quarterly, or more frequently.
    • Safeguard 6.1 : Establish an Access Granting Process: Establish and follow a process, preferably automated, for granting access to enterprise assets upon new hire, rights grant, or role change of a user.
    • Safeguard 6.2 : Establish an Access Revoking Process: Establish and follow a process, preferably automated, for revoking access to enterprise assets, through disabling accounts immediately upon termination, rights revocation, or role change of a user. Disabling accounts, instead of deleting accounts, may be necessary to preserve audit trails.
    • Safeguard 6.8: Define and Maintain Role-Based Access Control: Define and maintain role-based access control, through determining and documenting the access rights necessary for each role within the enterprise to successfully carry out its assigned duties. Perform access control reviews of enterprise assets to validate that all privileges are authorized, on a recurring schedule at a minimum annually, or more frequently.
  • Restrict execution of code to a virtual environment on or in transit to an endpoint system. (M1048: Application Isolation and Sandboxing)
    • Safeguard 16.8:  Separate Production and Non-Production Systems:  Maintain separate environments for production and non-production systems.
  • Vulnerability scanning is used to find potentially exploitable software vulnerabilities to remediate them. (M1016: Vulnerability Scanning)
    • Safeguard 7.1: Establish and Maintain a Vulnerability Management Process: Establish and maintain a documented vulnerability management process for enterprise assets. Review and update documentation annually, or when significant enterprise changes occur that could impact this Safeguard.
    • Safeguard 7.2: Establish and Maintain a Remediation Process: Establish and maintain a risk-based remediation strategy documented in a remediation process, with monthly, or more frequent, reviews.
    • Safeguard 7.6: Perform Automated Vulnerability Scans of Externally-Exposed Enterprise Assets: Perform automated vulnerability scans of externally-exposed enterprise assets using a SCAP-compliant vulnerability scanning tool. Perform scans on a monthly, or more frequent, basis.
    • Safeguard 7.7: Remediate Detected Vulnerabilities: Remediate detected vulnerabilities in software through processes and tooling on a monthly, or more frequent, basis, based on the remediation process.
    • Safeguard 16.13: Conduct Application Penetration Testing: Conduct application penetration testing. For critical applications, authenticated penetration testing is better suited to finding business logic vulnerabilities than code scanning and automated security testing.Penetration testing relies on the skill of the tester to manually manipulate an application as an authenticated and unauthenticated user.
    • Safeguard 18.1: Establish and Maintain a Penetration Testing Program: Establish and maintain a penetration testing program appropriate to the size, complexity, and maturity of the enterprise. Penetration testing program characteristics include scope, such as network, web application, Application Programming Interface (API), hosted services, and physical premise controls; frequency; limitations, such as acceptable hours, and excluded attack types; point of contact information; remediation, such as how findings will be routed internally; and retrospective requirements.
    • Safeguard 18.2: Perform Periodic External Penetration Tests: Perform periodic external penetration tests based on program requirements, no less than annually. External penetration testing must include enterprise and environmental reconnaissance to detect exploitable information. Penetration testing requires specialized skills and experience and must be conducted through a qualified party. The testing may be clear box or opaque box.
    • Safeguard 18.3: Remediate Penetration Test Findings: Remediate penetration test findings based on the enterprise’s policy for remediation scope and prioritization.
  • Use capabilities to detect and block conditions that may lead to or be indicative of a software exploit occurring. (M1050: Exploit Protection)
    • Safeguard 10.5:  Enable Anti-Exploitation Features: Enable anti-exploitation features on enterprise assets and software, where possible, such as Microsoft® Data Execution Prevention (DEP), Windows® Defender Exploit Guard (WDEG), or Apple® System Integrity Protection (SIP) and Gatekeeper™.
    • Safeguard 13.10:  Performing Application Layer Filtering:  Perform application layer filtering. Example implementations include a filtering proxy, application layer firewall, or gateway.
  • Inform and educate users regarding the threats posed by hypertext links contained in emails or attachments especially from un-trusted sources. Remind users not to visit un-trusted websites or follow links provided by unknown or un-trusted sources. (M1017: User Training)
    • Safeguard 14.1: Establish and Maintain a Security Awareness Program: Establish and maintain a security awareness program. The purpose of a security awareness program is to educate the enterprise’s workforce on how to interact with enterprise assets and data in a secure manner. Conduct training at hire and, at a minimum, annually. Review and update content annually, or when significant enterprise changes occur that could impact this Safeguard.
    • Safeguard 14.2: Train Workforce Members to Recognize Social Engineering Attacks: Train workforce members to recognize social engineering attacks, such as phishing, pre-texting, and tailgating.

 

 

REFERENCES:

Fortinet:

https://fortiguard.fortinet.com/psirt/FG-IR-22-398

 

CVE:

https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-42475

 

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