SAE IT-systems FW-50 Remote Telemetry Unit (RTU)
Act Now9.1ICS-CERT ICSA-20-126-02May 5, 2020
Attack VectorNetwork
Auth RequiredNone
ComplexityLow
User InteractionNone needed
Summary
The FW-50 RTU 5 Series CPU-5B contains input injection vulnerabilities (CWE-79 and CWE-22) in the web server. These vulnerabilities allow an attacker to execute remote code through malicious input or traverse the device's file system to access protected files. The web server does not adequately validate or sanitize user-supplied input before processing it.
What this means
What could happen
An attacker with network access to the RTU's web interface could run arbitrary code on the device or read sensitive files and configuration data that would normally be protected. This could allow unauthorized changes to telemetry settings, data exfiltration, or disruption of remote monitoring capabilities for water or power distribution systems.
Who's at risk
Water utilities and electric utilities operating SAE IT-systems FW-50 Remote Telemetry Units (RTUs) are affected. These devices are typically used for remote monitoring and control of distributed infrastructure such as pump stations, distribution lines, and remote substations. Any organization relying on this RTU model for telemetry collection should assess their exposure immediately.
How it could be exploited
An attacker sends malicious input (HTML, path traversal, or command injection) through the web server interface on the RTU. The web server does not properly validate or sanitize the input, allowing the attacker to execute arbitrary code on the CPU or access the device's file system to read configuration files, credentials, or system data.
Prerequisites
- Network access to port 80/443 on the RTU web server
- No authentication required to exploit the web server input injection vulnerability
- Web server port must be enabled (default condition)
Remotely exploitable over networkNo authentication requiredLow complexity attackHigh CVSS score (9.1)Critical severityAffects telemetry/monitoring systemsNo patch available from vendor
Exploitability
Low exploit probability (EPSS 0.5%)
Affected products (1)
ProductAffected VersionsFix Status
FW-50 RTU 5 Series CPU-5B: Hardware Revision 2; CPLD Revision 6Hardware Revision 2; CPLD Revision 6No fix yet
Remediation & Mitigation
0/4
Do now
0/3WORKAROUNDDisable the project web server port on the FW-50 RTU if the web interface is not required for normal operations
HARDENINGImplement network segmentation to isolate the RTU behind a firewall, blocking inbound traffic from the business network and Internet to the RTU's web server port
HARDENINGRestrict network access to the RTU to only authorized engineering workstations or SCADA master stations using firewall ACLs or network access control lists
Schedule — requires maintenance window
0/1Patching may require device reboot — plan for process interruption
HOTFIXReplace the CPU-5B card with a new hardware unit and reprogram it with the latest version of setIT software from SAE IT-systems
CVEs (2)
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