Insufficient Nonce Validation in Eclipse Milo Client

Impact

Credential replay affecting those connected to a server when all 3 of the following conditions are met:

• SecurityPolicy is None
• using username/password or X509-based authentication
• the server has a defect causing it to send null/empty or zeroed nonces

Patches

The problem has been patched in version 0.3.6. A more relaxed treatment of validation as agreed upon by the OPC UA Security Working Group is implemented in version 0.3.7.

Workarounds

Do not use username/password or X509-based authentication with SecurityPolicy of None.

References

https://opcfoundation.org/SecurityBulletins/OPC Foundation Security Bulletin CVE-2019-19135.pdf

For more information

If you have any questions or comments about this advisory:

• Open an issue at https://github.com/eclipse/milo/issues
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