A large number of authentication METHODs are available for hosts connecting using TCP/IP sockets, including: - trust - reject - md5 - scram-sha-256 - password - gss - sspi - ident - pam - ldap - radius - cert METHODs trust, password, and ident are not to be used for remote logins. METHOD md5 is the most popular and can be used in both encrypted and unencrypted sessions,however, it is vulnerable to packet replay attacks. It is recommended that scram-sha-256 be used instead of md5. Use of the gss, sspi, pam, ldap, radius, and cert METHODs, while more secure than md5, are dependent upon the availability of external authenticating processes/services and thus are not covered in this benchmark. NOTE: Nessus has not performed this check. Please review the benchmark to ensure target compliance.
Confirm a login attempt has been made by looking for a logged error message detailing the nature of the authenticating failure. In the case of failed login attempts, whether encrypted or unencrypted, check the following: - The server should be sitting on a port exposed to the remote connecting host i.e. NOT ip address 127.0.0.1 listen_addresses = '*' - An authenticating rule must exist in the file pg_hba.conf This example permits only encrypted sessions for the postgres role and denies all unencrypted session for the postgres role: # TYPE DATABASE USER ADDRESS METHOD hostssl all postgres 0.0.0.0/0 scram-sha-256 hostnossl all postgres 0.0.0.0/0 reject The following examples illustrate other possible configurations. The resultant 'rule' of success/failure depends upon the first matching line. # allow 'postgres' user only from 'localhost/loopback' connections # and only if you know the password # TYPE DATABASE USER ADDRESS METHOD host all postgres 127.0.0.1/32 scram-sha-256 # allow users to connect remotely only to the database named after them, # with the correct user password: # (accepts both SSL and non-SSL connections) # TYPE DATABASE USER ADDRESS METHOD host samerole all 0.0.0.0/0 scram-sha-256 # allow only those users who are a member of the 'rw' role to connect # only to the database named after them, with the correct user password: # (accepts both SSL and non-SSL connections) # TYPE DATABASE USER ADDRESS METHOD host samerole +rw 0.0.0.0/0 scram-sha-256 Default Value: The availability of the different password-based authentication methods depends on how a user's password on the server is encrypted (or hashed, more accurately). This is controlled by the configuration parameter password_encryption at the time the password is set. If a password was encrypted using the scram-sha-256 setting, then it can be used for the authentication methods scram-sha-256 and password (but password transmission will be in plain text in the latter case). The authentication method specification md5 will automatically switch to using the scram-sha-256 method in this case, as explained above, so it will also work. If a password was encrypted using the md5 setting, then it can be used only for the md5 and password authentication method specifications (again, with the password transmitted in plain text in the latter case). (Previous PostgreSQL releases supported storing the password on the server in plain text. This is no longer possible.) To check the currently stored password hashes, see the system catalog pg_authid. To upgrade an existing installation from md5 to scram-sha-256, after having ensured that all client libraries in use are new enough to support SCRAM, set password_encryption = 'scram-sha-256' in postgresql.conf, reload the postmaster, make all users set new passwords, and change the authentication method specifications in pg_hba.conf to scram-sha-256.