Encrypting sensitive data

You can prevent accidental exposure of passwords by encrypting sensitive configuration properties in the minifi.properties file. Learn how to encrypt sensitive data.

MiNiFi provides a encrypt-config tool (encrypt-config.exe on Windows) located in the bin directory of your installation, next to the main MiNiFi binary. This tool allows you to encrypt sensitive configuration properties in the minifi.properties file and also encrypts f the flow configuration (config.yml by default).

The security of the encryption relies on the security of the bootstrap.conf file, which stores the encryption key.

The terminologies used in this section are as follows:

minifi home

The directory specified by the --minifi-home option to encrypt-config.

configuration directory

The <minifi home>/conf directory.

properties file

The <minifi home>/conf/minifi.properties file.

flow configuration

The file specified in the properties file with the key nifi.flow.configuration.file. If not specified, it defaults to <minifi home>/conf/config.yml.

bootstrap file

The <minifi home>/conf/bootstrap.conf file.

sensitive property

Any property in the properties file that you wish to encrypt.

Encryption of the configuration properties

If you have a minifi.properties file in your MiNiFi configuration directory /var/tmp/minifi-home/conf containing the following sensitive properties:
You can run the encrypt-config tool as shown in the following example:
$ ./bin/encrypt-config --minifi-home /var/tmp/minifi-home
Generating a new encryption key...
Wrote the new encryption key to /var/tmp/minifi-home/conf/bootstrap.conf
Encrypted property: nifi.security.client.pass.phrase
Encrypted property: nifi.rest.api.password
Encrypted 2 sensitive properties in /var/tmp/minifi-home/conf/minifi.properties
The tool performs the following actions:
  1. It generates a new encryption key.
  2. It creates a bootstrap.conf file in your configuration directory and writes the encryption key to this file.
  3. It encrypts the sensitive properties using this encryption key.
  4. It adds a something.protected encryption marker after each encrypted property.
After running the tool, the bootstrap.conf and minifi.properties files will look like as shown in the following examples:

Additional sensitive properties

By default, encrypt-config encrypts a short list of default sensitive properties. To encrypt more properties, add a nifi.sensitive.props.additional.keys setting with a comma-separated list of additional sensitive properties to your minifi.properties file before running the encrypt-config tool. For example:

The tool encrypts these additional properties. You can also do this after you have already encrypted some properties. In that case, the tool encrypts the additional properties using the existing encryption key and leaves the other, already encrypted, sensitive properties intact.

Modifying sensitive properties

If you later need to modify the value of a sensitive property that was encrypted earlier, perform the following steps:
  1. Replace the encrypted value with the new unencrypted value.
  2. Delete the something.protected=... line added by the tool.
  3. Re-run the encrypt-config tool.

The tool encrypts the modified property using the existing encryption key in bootstrap.conf and leaves the other, already encrypted, sensitive properties intact.

Encryption of the flow definition

To encrypt the flow configuration file, pass the --encrypt-flow-config flag to encrypt-config. This encrypts the flow configuration file, not just the sensitive properties.

Updating the encryption key

To change the encryption key, perform the following steps:
  1. If files are already encrypted, there should be a nifi.bootstrap.sensitive.key=... line in the bootstrap.conf file (that is, have access to the original key). If not, manually replace all encrypted data (sensitive properties and flow configuration) with their original, unencrypted values (or some other new value).
  2. If present, rename the nifi.bootstrap.sensitive.key=... property in bootstrap.conf to nifi.bootstrap.sensitive.key.old=... (that is, add .old suffix to the property name).
  3. If you have a specific encryption key, add it to the bootstrap.conf file (as nifi.bootstrap.sensitive.key=<your encryption key here>). If you provide no encryption key (no nifi.bootstrap.sensitive.key property in bootstrap.conf, or no bootstrap.conf at all), a new key is randomly generated and written to bootstrap.conf.
  4. Re-run the encrypt-config tool.
$ cat /var/tmp/minifi-home/conf/bootstrap.conf
$ ./bin/encrypt-config --minifi-home /var/tmp/minifi-home
Old encryption key found in conf/bootstrap.conf
Using the existing encryption key found in conf/bootstrap.conf
Successfully decrypted property "nifi.security.client.pass.phrase" using old key.
Encrypted property: nifi.security.client.pass.phrase
Encrypted 1 sensitive property in conf/minifi.properties
WARNING: you did not request the flow config to be updated, if it is currently encrypted and the old key is removed, you won't be able to recover the flow config.

If you forgot to specify the --encrypt-flow-config flag, you can re-run encrypt-config with the flag, and it re-encrypts the flow configuration file, as well.

It is always safe to re-run encrypt-config. If it does not find anything new to encrypt, it does not do anything.

When you have successfully re-encrypted all sensitive properties and the flow configuration file(s), you can delete the nifi.bootstrap.sensitive.key.old line from the bootstrap file.

Automatic encryption

Specify the property nifi.flow.configuration.encrypt=true, in the properties file to have the new flow configuration written to the disk encrypted after a flow update (originating from a C2 server). It requires that you have a conf/bootstrap.conf in your minifi home, containing an encryption key (nifi.bootstrap.sensitive.key). This master key is also used on agent startup to decrypt the flow configuration file.