Private keys leaked in logs

[dextercd]

Hey there,

When you open an issue on this project, a comment from GitHub actions tells you to provide logs with --debug 2 set. However, sometimes these logs contain private keys. This means that people occasionally post the private keys for their publicly trusted certificates.

Here are some instances where this has happened:

---

#6165

-----BEGIN EC PRIVATE KEY-----
MHcCAQEEIMs4tSuTqBFPsTwVDvPmU2+9zfprjRTn/p9EaQWWvkJNoAoGCCqGSM49
AwEHoUQDQgAE8ngffyDE+hIUoNz1umHlWG/CuY1TqpSDRrZYvHyfOkKdnH/mrYUa
gZr+O1fNQWWaN8BKHe6nkOcAD8mMTG14uw==
-----END EC PRIVATE KEY-----

Certificate: https://crt.sh/?id=16142264126

---

#5004 (comment)

-----BEGIN EC PRIVATE KEY-----
MHcCAQEEIBhqGS/2Ucnoe+weM2oTNWlQbmCG6tr5hwiQDMxS0gShoAoGCCqGSM49
AwEHoUQDQgAEZ1B5WYmbpfFOMG+9FUrc0/y0TiXffNUe5YcUWuVgNz57aab8+Pyh
CBf92/cbkwZQbHgip7hjghwflTjuAqVMfQ==
-----END EC PRIVATE KEY-----

Certificate: https://crt.sh/?id=13108850004

---

#4788 (comment)

-----BEGIN EC PRIVATE KEY-----
MHcCAQEEIKqkk1rZcu4/tD+fYh6SrLX8QBzWyIpRyUhJkgItok6YoAoGCCqGSM49
AwEHoUQDQgAEj7fUB56An+/SwBPDwKm0+c2Jx4VPhak5YMMGYUr76vY+Ky8KYPg5
pJrhobIEtMkTLzltcjGGFmB62kuRK6NJsw==
-----END EC PRIVATE KEY-----

Certificate: https://crt.sh/?id=10532645172

---

None of these keys are currently being used. The certificates have either expired or been revoked. But this could definitely happen again in the future with valid certificates.

While it's up to each individual to make sure they're not sharing logs/files with important secrets, I think tools like acme.sh should also avoid logging this information, especially by default (e.g., it should require an opt-in flag like --output-insecure).

My suggestions:

• Don't log private keys without --output-insecure
  • haproxy.sh is affected CC: @wlallemand
  • synology_dsm.sh also appears to be affected because _post() logs the request body
  • Perhaps more?
• Include a warning in the GitHub actions comment telling the person to check logs for secrets before sharing them.
• Consider changing acme.sh's defaults, so it generates a new private key when renewing certificates.
  • Default to force new private key  #1308
  • This limits the impact when someone leaks their key.

[github-actions]

Please upgrade to the latest code and try again first. Maybe it's already fixed. acme.sh --upgrade If it's still not working, please provide the log with --debug 2, otherwise, nobody can help you.

[wlallemand]

hi @dextercd, I checked the haproxy.sh part, and you are right, we probably need to replace the "_debug" helper by "_secure_debug" to fix this. Since we need to pass the private key on the socat command, we could probably do a sed on the "BEGIN PRIVATE KEY" header when doing an insecure debug so we could still see the commands sent to HAProxy.

Maybe this filtering could be done in acme.sh _debug function directly, so any new contributor don't make this mistake. @Neilpang what do you think?

[wlallemand]

I made the pull request to fix the problem in haproxy.sh.