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Post-Quantum Key Exchange Warning on SSH Connection #1

@catsizedcoder

Description

@catsizedcoder

Hello there Zach. Cassidy here.
When connecting to this server via SSH, the following warning is displayed:

** WARNING: connection is not using a post-quantum key exchange algorithm.
** This session may be vulnerable to "store now, decrypt later" attacks.
** The server may need to be upgraded. See https://openssh.com/pq.html

The server's OpenSSH configuration does not use any post-quantum key exchange algorithms. This exposes sessions to harvest-now-decrypt-later attacks, where an attacker could record encrypted traffic today and decrypt it once sufficiently capable quantum hardware exists.

Steps to reproduce

  • Connect via ssh zachl.tech -p 2222 on the latest version of OpenSSH
  • Observe the warning printed before the shell opens

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