1. EXECUTIVE SUMMARY

  • CVSS v3 9.8
  • ATTENTION: Exploitable remotely/low skill level to exploit
  • Vendor: Mitsubishi Electric
  • Equipment: GOT2000 Series
  • Vulnerabilities: Improper Restriction of Operations within the Bounds of a Memory Buffer, Session Fixation, NULL Pointer Dereference, Improper Access Control, Argument Injection, Resource Management Errors
     

2. RISK EVALUATION

Successful exploitation of these vulnerabilities could allow a remote attacker to cause a denial-of-service condition or remote code execution.

3. TECHNICAL DETAILS

3.1 AFFECTED PRODUCTS

The following models of GOT2000 CoreOS Version -Y and earlier are affected:

  • GT27 model
  • GT25 model
  • GT23 model

3.2 VULNERABILITY OVERVIEW

3.2.1    IMPROPER RESTRICTION OF OPERATIONS WITHIN THE BOUNDS OF A MEMORY BUFFER CWE-119

The vulnerability could allow a malicious attacker to crash the device, which could lead to remote code execution.

CVE-2020-5595 has been assigned to this vulnerability. A CVSS v3 base score of 9.8 has been assigned; the CVSS vector string is (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H).

3.2.2    SESSION FIXATION CWE-384

The vulnerability could allow a malicious attacker to cause a denial-of-service of TCP connection.

CVE-2020-5596 has been assigned to this vulnerability. A CVSS v3 base score of 7.5 has been assigned; the CVSS vector string is (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).

3.2.3    NULL POINTER DEREFERENCE CWE-476

The vulnerability could allow a malicious attacker to cause a denial-of-service condition and crash the device.

CVE-2020-5597 has been assigned to this vulnerability. A CVSS v3 base score of 7.5 has been assigned; the CVSS vector string is (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).

3.2.4    IMPROPER ACCESS CONTROL CWE-284

The vulnerability could allow a malicious attacker authentication to access sensitive resources, cause a denial-of-service condition, and crash the device.

CVE-2020-5598 has been assigned to this vulnerability. A CVSS v3 base score of 9.8 has been assigned; the CVSS vector string is (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H).

3.2.5    IMPROPER NEUTRALIZATION OF ARGUMENT DELIMITERS IN A COMMAND (‘ARGUMENT INJECTION’) CWE-88

The vulnerability could allow an attacker to cause a denial-of-service condition.

CVE-2020-5599 has been assigned to this vulnerability. A CVSS v3 base score of 7.1 has been assigned; the CVSS vector string is (AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H).

3.2.6    RESOURCE MANAGEMENT ERRORS CWE-399

The vulnerability could allow an attacker to obtain sensitive information.

CVE-2020-5600 has been assigned to this vulnerability. A CVSS v3 base score of 5.3 has been assigned; the CVSS vector string is (AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N).
 

3.3 BACKGROUND

  • CRITICAL INFRASTRUCTURE SECTORS: Multiple
  • COUNTRIES/AREAS DEPLOYED: Worldwide
  • COMPANY HEADQUARTERS LOCATION: Japan

3.4 RESEARCHER

Mitsubishi Electric PSIRT reported these vulnerabilities to CISA.

4. MITIGATIONS

Mitsubishi recommends users follow the steps below to update CoreOS to the latest version:

  1. Install the MELSOFT GT Designer3 (2000) Version 1.240A or later on your personal computer.
  2. Start the MELSOFT GT Designer3 and copy CoreOS of Version -Z or later to SD card.
  3. Insert the SD card removed from the personal computer to the target products and update to the latest version of CoreOS.

Please contact your local Mitsubishi sales office about MELSOFT GT Designer3 (2000).

CISA recommends users take defensive measures to minimize the risk of exploitation of this vulnerability. Specifically, users should:

  • Minimize network exposure for all control system devices and/or systems, and ensure that they are not accessible from the Internet.
  • Locate control system networks and remote devices behind firewalls, and isolate them from the business network.
  • When remote access is required, use secure methods, such as Virtual Private Networks (VPNs), recognizing that VPNs may have vulnerabilities and should be updated to the most current version available. Also recognize that VPN is only as secure as the connected devices.

CISA reminds organizations to perform proper impact analysis and risk assessment prior to deploying defensive measures.

CISA also provides a section for control systems security recommended practices on the ICS webpage on us-cert.gov. Several recommended practices are available for reading and download, including Improving Industrial Control Systems Cybersecurity with Defense-in-Depth Strategies.

Additional mitigation guidance and recommended practices are publicly available on the ICS webpage on us-cert.gov in the Technical Information Paper, ICS-TIP-12-146-01B–Targeted Cyber Intrusion Detection and Mitigation Strategies.

Organizations observing any suspected malicious activity should follow their established internal procedures and report their findings to CISA for tracking and correlation against other incidents.

No known public exploits specifically target these vulnerabilities.

Source:

https://us-cert.cisa.gov/ics/advisories/icsa-20-189-02