​Digi RealPort Protocol

1. EXECUTIVE SUMMARY

• ​CVSS v3 9.0
• ​ATTENTION: Exploitable remotely
• ​Vendor: Digi International, Inc.
• ​Equipment: Digi RealPort Protocol
• ​Vulnerability: Use of Password Hash Instead of Password for Authentication

2. RISK EVALUATION

​Successful exploitation of this vulnerability could allow the attacker to access connected equipment.

3. TECHNICAL DETAILS

3.1 AFFECTED PRODUCTS

​Digi International reports that the following products using Digi RealPort Protocol are affected:

• ​Digi RealPort for Windows: version 4.8.488.0 and earlier
• ​Digi RealPort for Linux: version 1.9-40 and earlier
• ​Digi ConnectPort TS 8/16: versions prior to 2.26.2.4
• ​Digi Passport Console Server: all versions
• ​Digi ConnectPort LTS 8/16/32: versions prior to 1.4.9
• ​Digi CM Console Server: all versions
• ​Digi PortServer TS: all versions
• ​Digi PortServer TS MEI: all versions
• ​Digi PortServer TS MEI Hardened: all versions
• ​Digi PortServer TS M MEI: all versions
• ​Digi PortServer TS P MEI: all versions
• ​Digi One IAP Family: all versions
• ​Digi One IA: all versions
• ​Digi One SP IA: all versions
• ​Digi One SP: all versions
• ​Digi WR31: all versions
• ​Digi WR11 XT: all versions
• ​Digi WR44 R: all versions
• ​Digi WR21: all versions
• ​Digi Connect ES: versions prior to 2.26.2.4
• ​Digi Connect SP: all versions

​Digi International reports that the following products do NOT use Digi RealPort Protocol are NOT affected:

• ​Digi 6350-SR: all versions
• ​Digi ConnectCore 8X products: all versions

3.2 VULNERABILITY OVERVIEW

3.2.1 ​USE OF PASSWORD HASH INSTEAD OF PASSWORD FOR AUTHENTICATION CWE-836

​Digi RealPort Protocol is vulnerable to a replay attack that may allow an attacker to bypass authentication to access connected equipment.

​CVE-2023-4299 has been assigned to this vulnerability. A CVSS v3 base score of 9.0 has been calculated; the CVSS vector string is (AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H).

3.3 BACKGROUND

• ​CRITICAL INFRASTRUCTURE SECTORS: Multiple Sectors
• ​COUNTRIES/AREAS DEPLOYED: Worldwide
• ​COMPANY HEADQUARTERS LOCATION: United States

3.4 RESEARCHER

​Reid Wightman of Dragos, Inc reported this vulnerability to Digi International.

4. MITIGATIONS

​Digi International recommends users acquire and install patches that they have made available for the following products:

• ​RealPort software for Windows: Fixed in 4.10.490
• ​Digi ConnectPort TS 8/16: Fixed in firmware version 2.26.2.4
• ​Digi ConnectPort LTS 8/16/32: Fixed in version 1.4.9
• ​Digi Connect ES: Fixed in firmware version 2.26.2.4

​For more information, see the customer notification document published by Digi International.

​Dragos recommends restricting access to Digi devices on TCP/771 (default) or TCP/1027 (if encryption is enabled, this is the default port). Only allow the workstations which initiate RealPort connections to communicate to the field equipment on those ports. Note that most of Digi's devices allow you to change the setting for which TCP port the RealPort service runs on, so end users should consult their device configuration and restrict access to the configured port if it is not the default.

​If using the system in 'reverse' mode, where the Digi device calls back to the Windows or Linux workstation, then Dragos recommends restricting access to the workstation on TCP/771 or TCP/1027 to known Digi RealPort devices on your network. This port may be configured by end users, so consult the workstation and device configurations to ensure coverage.

​CISA recommends users take defensive measures to minimize the risk of exploitation of this vulnerability. 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 at cisa.gov/ics. Several CISA products detailing cyber defense best 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 at cisa.gov/ics in the technical information paper, ICS-TIP-12-146-01B--Targeted Cyber Intrusion Detection and Mitigation Strategies.

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

​​No known public exploitation specifically targeting this vulnerability has been reported to CISA at this time. This vulnerability has a high attack complexity.