I used to install ssh_locker [1] (I don’t know if it still works), and have the passphrase in a keychain separate from the default `login` that I then set in Keychain Access to autolock after a set period of time. Handy for keeping the private key for a while in RAM and then autoremoved, instead of having it there for the whole session. It worked transparently and is a feature that should come with the OS.

[1]: https://github.com/ddribin/ssh_locker

ChatGPT says ssh_locker locked the keys with `ssh-add -x` which doesn’t necessarily remove them from RAM. Duh! It does point to suggested minimal changes to its source code to effectively accomplish that though.

Being able to extract a private key from ssh-agent's PR_SET_DUMPABLE=0 process would be a kernel bug; if you're sitting on such a vulnerability, please consider reporting it.

So the malware modifies your environment to LD_PRELOAD something into ssh-agent instead on your next login? Stuff that runs inside your own session is inherently vulnerable to malware inside that, even if ptrace protections are a speedbump.