GaussDB Kernel: Revoking the CREATE Permission from a User with the PUBLIC Role

# Copyright (C) 2020 Greenbone Networks GmbH
# Some text descriptions might be excerpted from (a) referenced
# source(s), and are Copyright (C) by the respective right holder(s).
#
# SPDX-License-Identifier: GPL-2.0-or-later
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation; either version 2
# of the License, or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

if(description)
{
  script_oid("1.3.6.1.4.1.25623.1.0.150461");
  script_version("2020-11-20T12:35:19+0000");
  script_tag(name:"last_modification", value:"2020-11-20 12:35:19 +0000 (Fri, 20 Nov 2020)");
  script_tag(name:"creation_date", value:"2020-11-20 10:52:10 +0000 (Fri, 20 Nov 2020)");
  script_tag(name:"cvss_base", value:"0.0");
  script_tag(name:"cvss_base_vector", value:"AV:L/AC:H/Au:S/C:N/I:N/A:N");
  script_tag(name:"qod", value:"97");

  script_name("GaussDB Kernel: Revoking the CREATE Permission from a User with the PUBLIC Role");

  script_category(ACT_GATHER_INFO);
  script_copyright("Copyright (C) 2020 Greenbone Networks GmbH");
  script_family("Policy");
  script_dependencies("compliance_tests.nasl", "gb_huawei_gaussdb_kernel_ssh_login_detect.nasl", "gaussdbkernel_authentication_information.nasl");
  script_mandatory_keys("huawei/gaussdb_kernel/detected", "Compliance/Launch");

  script_tag(name:"summary", value:"A common user can create malicious functions with the same names as system
functions if the user has the PUBLIC role. In this way, other users can call these
malicious functions by mistake to compromise database security.
If the PUBLIC role has the CREATE permission, any user having this role can create,
view, and modify tables or other database objects in the tablespace of this role.
Therefore, it is recommended that the PUBLIC role do not have the CREATE
Permission.");

  exit(0);
}

include( "policy_functions.inc" );
include( "ssh_func.inc" );

cmd = "SELECT CAST(has_schema_privilege('public','public','CREATE') AS TEXT);";
title = "Revoking the CREATE Permission from a User with the PUBLIC Role";
solution = "REVOKE CREATE ON SCHEMA PUBLIC FROM public;";
default = "false";
test_type = "SQL_Query";

if( ! get_kb_item( "login/SSH/success" ) || ! sock = ssh_login_or_reuse_connection() ) {
  compliant = "incomplete";
  value = "error";
  comment = "No SSH connection to host";
}else if ( ! value = policy_gsql_cmd( socket:sock, query:cmd, db_type:"gaussdbkernel" ) ) {
  compliant = "incomplete";
  value = "error";
  comment = "SQL command did not return anything";
}else if ( value =~ "failed to connect" ) {
  compliant = "incomplete";
  value = "error";
  comment = "No connection to database";
}else{
  value = ereg_replace( string:chomp( value ), pattern:"^\s+", replace:"" );
  compliant = policy_setting_exact_match( value:value, set_point:default );
}

policy_reporting( result:value, default:default, compliant:compliant, fixtext:solution,
  type:test_type, test:cmd, info:comment );

policy_set_kbs( type:test_type, cmd:cmd, default:default, solution:solution, title:title,
  value:value, compliant:compliant );

exit( 0 );