My problems seems indeed to arise at shadow passwords when running dropbear as non-root user. Password for mysticbbs user is set during docker build with: passwd mysticbbs -d '' -uĪs pointed to by in comment, and the note at : Keys are generated during the docker build with the following: export RSA_KEYFILE=/etc/dropbear/dropbear_rsa_host_keyĮxport DSS_KEYFILE=/etc/dropbear/dropbear_dss_host_keyĮxport ECDSA_KEYFILE=/etc/dropbear/dropbear_ecdsa_host_keyĬhown -R mysticbbs:mysticbbs /etc/dropbear