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PHOENIX CONTACT: BLUEMARK X1 / LED / CLED printers utilizing the Siemens Nucleus RTOS TCP/IP Stack

Act Now9.8VDE-2021-059Jan 11, 2022
Attack VectorNetwork
Auth RequiredNone
ComplexityLow
User InteractionNone needed
Summary

The TCP/IP stack in the Nucleus RTOS and its networking component (Nucleus NET) contain multiple critical vulnerabilities. BLUEMARK X1, LED, and CLED printers utilize this flawed stack and are susceptible to 8 of the 13 discovered vulnerabilities. These devices are discontinued and no patches will be released. Vulnerabilities include buffer overflows, integer underflows, and memory access violations that could allow remote attackers to execute code without authentication.

What this means
What could happen
An attacker with network access could exploit multiple vulnerabilities in the TCP/IP stack to gain unauthorized control of the printer, potentially disrupting label/marking operations or accessing sensitive data processed by the device.
Who's at risk
Organizations operating BLUEMARK X1, LED, or CLED industrial printers used for product marking and labeling in manufacturing, packaging, or utility operations should be concerned. These devices are commonly found in electrical equipment assembly, wire marking, and component labeling workflows.
How it could be exploited
An attacker on the network sends specially crafted packets to port 502 or other open network ports on the BLUEMARK printer. The flawed TCP/IP stack processes these packets without proper validation, allowing buffer overflows or memory corruption that could grant command execution on the device.
Prerequisites
  • Network access to the BLUEMARK printer (Ethernet)
  • Printer must be reachable from the attacker's network segment
  • No authentication required
remotely exploitableno authentication requiredlow complexityno patch availablediscontinued product
Affected products (3)
3 EOL
ProductAffected VersionsFix Status
BLUEMARK CLEDAll versionsNo fix (EOL)
BLUEMARK X1All versionsNo fix (EOL)
BLUEMARK LEDAll versionsNo fix (EOL)
Remediation & Mitigation
0/4
Do now
0/2
HARDENINGIsolate all BLUEMARK printers to a dedicated, closed network segment not connected to untrusted networks or the internet
WORKAROUNDDeploy a firewall rule to restrict inbound traffic to the BLUEMARK printer to only trusted workstations and engineering stations that genuinely need access
Schedule — requires maintenance window
0/1

Patching may require device reboot — plan for process interruption

HARDENINGDisable network access on the BLUEMARK printer if the device can operate in stand-alone mode without network connectivity
Mitigations - no patch available
0/1
The following products have reached End of Life with no planned fix: BLUEMARK CLED, BLUEMARK X1, BLUEMARK LED. Apply the following compensating controls:
HARDENINGPlan replacement or decommissioning of BLUEMARK X1 / LED / CLED units, as they are discontinued products with no vendor patches available
View full CERT@VDE advisory
API: /api/v1/advisories/083b473c-a6bd-4d92-bb7d-2accf5495b98