Share: Email | Twitter

ID

VDE-2020-019

Published

2020-06-16 10:31 (CEST)

Last update

2020-06-16 10:31 (CEST)

Vendor(s)

Beckhoff Automation GmbH & Co. KG

Product(s)

Article No┬░ Product Name Affected Version(s)
TwinCAT Driver for Intel 8254x for TwinCAT 2.11 2350 <= 2.11.0.2120
TwinCAT Driver for Intel 8254x for TwinCAT 3.1 4022 <= 3.1.0.3512
TwinCAT Driver for Intel 8254x for TwinCAT 3.1 4024 <= 3.1.0.3603
TwinCAT Driver for Intel 8255x for TwinCAT 2.11 2350 <= 2.11.0.2117
TwinCAT Driver for Intel 8255x for TwinCAT 3.1 402 <= 3.1.0.3600
TwinCAT Driver for Intel 8255x for TwinCAT 3.1 4024 <= 3.1.0.3500

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.


Last Update:

June 26, 2020, 2:12 p.m.

Weakness

Exposure of Sensitive Information to an Unauthorized Actor  (CWE-200) 

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. 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.


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.

Solution

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.

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. The advisory will be updated upon availability.

Reported by

Beckhoff reported the vulnerability to CERT@VDE