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WAGO: OpenSSL DoS Vulnerability in PLCs

VDE-2021-038
Last update
05/14/2025 14:53
Published at
08/31/2021 09:00
Vendor(s)
WAGO GmbH & Co. KG
External ID
VDE-2021-038
CSAF Document

Summary

WAGO controllers have always been designed for easy connection to IT infrastructure. Even controllers from legacy product lines support encryption standards to ensure secure communication.
With special crafted requests it is possible to bring the device out of operation.
All listed devices are vulnerable for this denial of service attack.

Impact

This vulnerability allows an attacker who has access to the device to send a series of maliciously constructed packets which can bring the device out of operation. The device needs a power on reset to go back to normal operation.

Affected Product(s)

Model no. Product name Affected versions
750-831/xxx-xxx Firmware <=FW15
750-880/xxx-xxx Firmware <=FW15
750-881 Firmware <=FW15
750-889 Firmware <=FW15

Vulnerabilities

Expand / Collapse all

Published
09/22/2025 14:58
Weakness
Missing Release of Resource after Effective Lifetime (CWE-772)
Summary

Missing Release of Resource after Effective Lifetime vulnerability in OpenSSL implementation of WAGO 750-831/xxx-xxx, 750-880/xxx-xxx, 750-881, 750-889 in versions FW4 up to FW15 allows an unauthenticated attacker to cause DoS on the device.

References

Mitigation

  • Restrict network access to the device.
  • Do not directly connect the device to the internet
  • Disable unused TCP/UDP-ports
  • Disable Web Based Management ports 80/443 after configuration phase.

Remediation

Update the device to the latest FW version.

Revision History

Version Date Summary
1 08/31/2021 09:00 Initial revision.
2 05/14/2025 14:53 Fix: version space, added distribution