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ID

VDE-2020-044

Published

2021-08-31 09:01 (CEST)

Last update

2021-09-08 09:51 (CEST)

Vendor(s)

WAGO

Product(s)

Product Affected Versions
750-362 <= FW07
750-363 <= FW07
750-823 <= FW07
750-832/xxx-xxx <= FW07
750-862 <= FW07
750-891 <= FW07
750-890/xxx-xxx <= FW07
750-893 <= FW07

Summary

The Web-Based Management (WBM) of WAGOs programmable logic controller (PLC) is typically used for administration, commissioning and updates.
With special crafted requests it is possible to read and write some special parameters without authentication.
This vulnerability is different to advisory SAV-2020-014 / VDE-2020-028.


Weakness

Improper Authentication  (CWE-287) 

Summary

This vulnerability allows an attacker who has access to the WBM to read and write settings-parameters of the device by sending specifically constructed requests without authentication on multiple WAGO PLCs in firmware versions up to FW07.

Impact

This vulnerability allows an attacker who has access to the WBM and knowledge about the directory structure of the WBM to read and/or write a settings-parameter of the devices by sending specifically constructed requests without authentication.
This can lead to malfunction of the application after reboot.

Solution

Update the device to the latest FW version.

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 the configuration phase

Reported by

Maxim Rupp (https://rupp.it) reported this vulnerability to WAGO.
CERT@VDE coordinated.