V-72999

control "V-72999" do

  title "PostgreSQL must separate user functionality (including user interface
services) from database management functionality."
  desc  "Information system management functionality includes functions necessary to
administer databases, network components, workstations, or servers and typically
requires privileged user access.

The separation of user functionality from information system management
functionality is either physical or logical and is accomplished by using different
computers, different central processing units, different instances of the operating
system, different network addresses, combinations of these methods, or other
methods, as appropriate.

An example of this type of separation is observed in web administrative interfaces
that use separate authentication methods for users of any other information system
resources.

This may include isolating the administrative interface on a different domain and
with additional access controls.

If administrative functionality or information regarding PostgreSQL management is
presented on an interface available for users, information on DBMS settings may be
inadvertently made available to the user."

  impact 0.5
  tag "severity": "medium"
  tag "gtitle": "SRG-APP-000211-DB-000122"
  tag "gid": "V-72999"
  tag "rid": "SV-87651r1_rule"
  tag "stig_id": "PGS9-00-008500"
  tag "cci": "CCI-001082"
  tag "nist": ["SC-2", "Rev_4"]

  tag "check": "Check PostgreSQL settings and vendor documentation to verify that
administrative functionality is separate from user functionality.

As the database administrator (shown here as \"postgres\"), list all roles and
permissions for the database:

$ sudo su - postgres
$ psql -c \"\\du\"

If any non-administrative role has the attribute \"Superuser\", \"Create role\",
\"Create DB\" or \"Bypass RLS\", this is a finding.

If administrator and general user functionality are not separated either physically
or logically, this is a finding."
  tag "fix": "Configure PostgreSQL to separate database administration and general
user functionality.

Do not grant superuser, create role, create db or bypass rls role attributes to
users that do not require it.

To remove privileges, see the following example:

ALTER ROLE <username> NOSUPERUSER NOCREATEDB NOCREATEROLE NOBYPASSRLS;"

  privileges = %w(rolcreatedb rolcreaterole rolsuper)
  sql = postgres_session(PG_DBA, PG_DBA_PASSWORD, PG_HOST)

  roles_sql = 'SELECT r.rolname FROM pg_catalog.pg_roles r;'
  roles_query = sql.query(roles_sql, [PG_DB])
  roles = roles_query.lines

  roles.each do |role|
    unless PG_SUPERUSERS.include?(role)
      privileges.each do |privilege|
        privilege_sql = "SELECT r.#{privilege} FROM pg_catalog.pg_roles r "\
          "WHERE r.rolname = '#{role}';"

        describe sql.query(privilege_sql, [PG_DB]) do
          its('output') { should_not eq 't' }
        end
      end
    end
  end
end