VDE-2021-051

csafDEbeckhoff_psirt

Beckhoff: Relative path traversal vulnerability through TwinCAT OPC UA Server

view advisory published 2021-11-04

Through specific nodes of the server configuration interface of the TwinCAT OPC UA Server administrators are able to remotely create and delete any files on the system which the server is running on, though this access should have been restricted to specific directories. In case that configuration interface is combined with not recommended settings to allow anonymous access via the TwinCAT OPC UA Server then this kind of file access is even possible for any unauthenticated user from remote.

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describes (1)

Related CVEs.

IDseverity exploitable
CVE-2021-34594USmedium6.5—
TwinCAT OPC UA Server in TF6100 and TS6100 in product versions before 4.3.48.0 or with TcOpcUaServer versions below 3.2.0.194 are prone to a relative path traversal that allow admi…
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references

External citations — patches, advisories, analysis.

03

remediations (2)

  • Mitigation

    Consider restricting access to the nodes of the 'TcOpcUAServer' with the methods described by https://infosys.beckhoff.com/content/1033/tcopcuaserver/5930038411-1.html such that the administrative interface can only be accessed by administrative users of well known OPC UA clients.

  • Fixed

    Please update to a recent version of the affected product.

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