Beckhoff TwinCAT 3 supports communication over ADS. ADS is a protocol for industrial automation in protected environments. This protocol uses user configured routes, that can be edited remotely via ADS. This special command supports encrypted authentication with username/password. The encryption uses a fixed key, that could be extracted by an attacker. Precondition of the exploitation of this weakness is network access at the moment a route is added.

References

• https://nvd.nist.gov/vuln/detail/CVE-2017-16718
• https://download.beckhoff.com/download/Document/product-security/Advisories/advisory-2017-002.pdf