1. EXECUTIVE SUMMARY

  • CVSS v3 9.8
  • ATTENTION: Exploitable remotely/low skill level to exploit
  • Vendor: GE
  • Equipment: Reason RT43X Clocks
  • Vulnerabilities: Code Injection, Use of Hard-coded Cryptographic Key

2. RISK EVALUATION

Successful exploitation of these vulnerabilities could allow an authenticated remote attacker to execute arbitrary code on the system or intercept and decrypt encrypted traffic.

3. TECHNICAL DETAILS

3.1 AFFECTED PRODUCTS

GE reports the vulnerabilities affect the following GNSS clocks: 

  • RT430, RT431 & RT434: All firmware versions prior to Version 08A06

3.2 VULNERABILITY OVERVIEW

3.2.1    IMPROPER CONTROL OF GENERATION OF (CODE INJECTION) CWE-94

A code injection vulnerability exists in one of the webpages that could allow an authenticated remote attacker to execute arbitrary code on the system. 

CVE-2020-25197 has been assigned to this vulnerability. A CVSS v3 base score of 9.8 has been calculated; the CVSS vector string is (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H).

3.2.2    USE OF HARD-CODED CRYPTOGRAPHIC KEY CWE-321

By having access to the hard-coded cryptographic key, attackers would be able to intercept and decrypt encrypted traffic through an HTTPS connection. 

CVE-2020-25193  has been assigned to this vulnerability. A CVSS v3 base score of 5.3 has been calculated; 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: Communications, Critical Manufacturing, Energy, Healthcare and Public Health, Transportation Systems, Water and Wastewater Systems
  • COUNTRIES/AREAS DEPLOYED: Worldwide
  • COMPANY HEADQUARTERS LOCATION: United States

3.4 RESEARCHER

Tom Westenberg of Thales UK reported these vulnerabilities to GE.

4. MITIGATIONS

GE strongly recommends users of Reason RT43X products update their units to firmware Version 08A06 or greater to resolve these issues. The firmware update addresses both vulnerabilities as described in the Reason RT43X 08A06 Release Notes.

GE recommends users evaluate current risk and implement appropriate network security mitigation measures as follows. The following mitigation actions do not ensure complete security but should be considered until the affected time synchronization product is upgraded:

  • Use strong network and physical security protection to prevent an attacker from reaching the local network where Reason RT43X clocks are normally installed. 
  • Block TCP/IP Ports 80 and 443 to block the HTTP/HTTPS access to web interface with Reason RT43X products, avoiding all the vulnerabilities. This TCP/IP port blocking should be limited to the Ethernet port interface where the Reason RT43X clock is connected (e.g., using Access Control List (ACL)). Otherwise, other HTTP/HTTPS applications may be affected.
  • Minimize network exposure for all control system devices and/or systems and ensure they are not accessible from the Internet.
  • Analyze security events to early detect unexpected traffic/communication.

Please see GE publication GES-2020-006 (login required) for more details on these issues.

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

  • 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.cisa.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.cisa.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-21-005-03