Skip to content
OpenAdvisories
Medium VDE-2020-019 1 CVE

Beckhoff: EtherLeak in TwinCAT RT network driver

Published Jun 16, 2020 · Updated May 22, 2025 · Revision 4

Vendor: Beckhoff Product: TwinCAT 2.11 2350 Product: TwinCAT 3.1 402 Product: TwinCAT 3.1 4022 Product: TwinCAT 3.1 4024 Product: TwinCAT Driver for Intel 8255x

Summary

Beckhoff's TwinCAT RT network driver for Intel 8254x and 8255x is providing EtherCAT functionality. The driver implements real-time features. Except for Ethernet frames sent from real-time functionality, all other Ethernet frames sent through the driver are not padded if their payload is less than the minimum Ethernet frame size. Instead, arbitrary memory content is transmitted within in the padding bytes of the frame. Most likely this memory contains slices from previously transmitted or received frames.

Details

Impact
By this method, memory content is disclosed, however, an attacker can hardly control which memory content is affected. For example, the disclosure can be provoked with small sized ICMP echo requests sent to the device.

Remediation
Beckhoff offers software patches for TwinCAT 3.1 and TwinCAT 2.11 on request. These patches will be included in the the next regular releases to the affected software versions.

Mitigation
If no real-time communication from TwinCAT is required on the Ethernet interface, then users can alternatively re-configure them to use the Intel ® driver, which is shipped with Beckhoff images.

Customers should configure a perimeter firewall to block traffic from untrusted networks to the device, especially regarding ICMP and other small ethernet frames.

Vulnerabilities 1

Revision history

  1. #4

    Fix: added distribution, quotation mark

  2. #3

    Fix: version range

  3. #2

    Fix: added self-reference

  4. #1

    Initial revision.

References