Password Security
Local passwords stored by the Model Manager server are hashed by 100,000 iterations of the PBKDF2WithHmacSHA256 algorithm. This means that an adversary that gets access to the hashed passwords will not easily be able to obtain the original passwords. However, if an adversary does obtain a local password (for example, by brute-force guessing a weak password), the adversary could log in to the Model Manager server.
By default, the Model Manager server writes hashed local passwords to the file /db/settings/local.db in the Preference Directory. The temporary password set for the Default Local Administrative User during installation is stored using the same hash algorithm in the file tempadminlogin.properties in the root of the installation directory.
As mentioned previously, it is recommended to use TLS (via HTTPS) to protect passwords sent from web browsers and COMSOL Multiphysics to the Model Manager server. A warning appears in COMSOL Multiphysics at the time of login if the connection to the Model Manager server is not secure. Web browsers will show similar warnings.
Passwords saved in COMSOL Multiphysics for connecting to the Model Manager server (“Remember password”) are stored encrypted so that only the logged-in user can access them. On Windows®, the encryption is done using the Data Protection API of the operating system. On Linux® and macOS, the encryption is done using a master key stored in the preference directory, protected by file system permissions. The same encryption is used to protect passwords stored by a Model Manager server configured to connect to external SQL database servers or Apache Solr™ servers using password-based authentication methods — see also Databases with External Server Components.
When a COMSOL Multiphysics client is connected to a COMSOL Multiphysics server on another host computer, the communication is typically on a nonsecure channel. This means that Model Manager server passwords entered in the user interface on the client computer are sent to the COMSOL Multiphysics server computer in an unencrypted cleartext format. To prevent this exposure, either tunnel the connection between the COMSOL Multiphysics client and the COMSOL Multiphysics server using a secure SSH tunnel, or first enter and save the Model Manager server credentials using a local COMSOL Multiphysics instance running on the COMSOL Multiphysics server computer. A Model Manager server password already saved on the COMSOL Multiphysics server computer is not sent to the COMSOL Multiphysics client computer when connecting to a Model Manager server.