We have a script that’s used to securely retrieve passwords … a script which failed when run from a Docker container.

* could not load PEM client certificate, OpenSSL error error:140AB18E:SSL routines:SSL_CTX_use_certificate:ca md too weak, (no key found, wrong pass phrase, or wrong file format?)

Appears root of issue is tied to Debian OS that’s used in the python:3.7-slim container that’s being used. Newer iterations of some Linux OS’s have a default setting in the openssl config that provide a setting for SSL_CTX_set_security_level that precludes communication with password server.

Remediating this at the server end is not a reasonable approach, so client config needs to be changed to allow connection to be established. Setting security level to 1 allows connection to proceed, so proposed including additional instruction in Dockerfile that uses sed to update the configuration parameter.

sed -i 's/DEFAULT@SECLEVEL=2/DEFAULT@SECLEVEL=1/' /etc/ssl/openssl.cnf

Once that setting was updated, the script worked perfectly as it does on our physical and VM servers.