Electrolink FM/DAB/TV Transmitter

1. EXECUTIVE SUMMARY

• CVSS v3 8.8
• ATTENTION: Exploitable remotely/low attack complexity/public exploits are available
• Vendor: Electrolink
• Equipment: FM/DAB/TV Transmitter
• Vulnerabilities: Authentication Bypass by Assumed-Immutable Data, Reliance on Cookies without Validation and Integrity Checking, Missing Authentication for Critical Function, Cleartext Storage of Sensitive Information

2. RISK EVALUATION

Successful exploitation of these vulnerabilities could allow an attacker to obtain full system access, keep the device from transmitting, escalate privileges, change credentials, and execute arbitrary code.

3. TECHNICAL DETAILS

3.1 AFFECTED PRODUCTS

The following Electrolink transmitters are affected:

• 10W, 100W, 250W, Compact DAB Transmitter
• 500W, 1kW, 2kW Medium DAB Transmitter
• 2.5kW, 3kW, 4kW, 5kW High Power DAB Transmitter
• 100W, 500W, 1kW, 2kW Compact FM Transmitter
• 3kW, 5kW, 10kW, 15kW, 20kW, 30kW Modular FM Transmitter
• 15W – 40kW Digital FM Transmitter
• BI, BIII VHF TV Transmitter
• 10W – 5kW UHF TV Transmitter

3.2 Vulnerability Overview

3.2.1 Authentication Bypass by Assumed-Immutable Data CWE-302

Electrolink transmitters are vulnerable to an authentication bypass vulnerability affecting the login cookie. An attacker can set an arbitrary value except ‘NO’ to the login cookie and have full system access.

3.2.2 Authentication Bypass by Assumed-Immutable Data CWE-302

The application is vulnerable to an unauthenticated parameter manipulation that allows an attacker to set the credentials to blank giving her access to the admin panel. Also vulnerable to account takeover and arbitrary password change.

3.2.3 Reliance on Cookies without Validation and Integrity Checking CWE-565

The application suffers from a privilege escalation vulnerability. An attacker logged in as guest can escalate his privileges by poisoning the cookie to become administrator.

3.2.4 Reliance on Cookies without Validation and Integrity Checking CWE-565

The device allows an unauthenticated attacker to bypass authentication and modify the cookie to reveal hidden pages that allows more critical operations to the transmitter.

3.2.5 Missing Authentication for Critical Function CWE-306

An unauthenticated attacker can reset the board and stop transmitter operations by sending a specially-crafted GET request to the command.cgi gateway, resulting in a denial-of-service scenario.

3.2.6 Missing Authentication for Critical Function CWE-306

The devices allow access to an unprotected endpoint that allows MPFS file system binary image upload without authentication. The MPFS2 file system module provides a light-weight read-only file system that can be stored in external EEPROM, external serial flash, or internal flash program memory. This file system serves as the basis for the HTTP2 web server module, but is also used by the SNMP module and is available to other applications that require basic read-only storage capabilities. This can be exploited to overwrite the flash program memory that holds the web server’s main interfaces and execute arbitrary code.

3.2.7 Cleartext Storage of Sensitive Information CWE-312

Electrolink transmitters store credentials in clear-text. Use of these credentials could allow an attacker to access the system.

3.3 BACKGROUND

• CRITICAL INFRASTRUCTURE SECTORS: Communications Sector
• COUNTRIES/AREAS DEPLOYED: Worldwide
• COMPANY HEADQUARTERS LOCATION: Italy

3.4 RESEARCHER

Gjoko Krstic publicly reported these vulnerabilities on the internet after an unsuccessful attempt to contact Electrolink directly.

4. MITIGATIONS

Electrolink has not responded to requests to work with CISA to mitigate these vulnerabilities. Users of the affected products are encouraged to contact Electrolink for additional information.

CISA recommends users take defensive measures to minimize the risk of exploitation of these vulnerabilities, such as:

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

No known public exploitation specifically targeting these vulnerabilities has been reported to CISA at this time.

5. UPDATE HISTORY

• April 16, 2024: Initial Publication

https://www.cisa.gov/news-events/ics-advisories/icsa-24-107-02