Huawei Data Communication: The length of the host public key does not meet security requirements

# Copyright (C) 2021 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("1.3.6.1.4.1.25623.1.0.150678");
  script_version("2021-10-22T11:14:32+0000");
  script_tag(name:"last_modification", value:"2021-10-22 11:14:32 +0000 (Fri, 22 Oct 2021)");
  script_tag(name:"creation_date", value:"2021-06-17 11:41:38 +0000 (Thu, 17 Jun 2021)");
  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("Huawei Data Communication: The length of the host public key does not meet security requirements");

  script_category(ACT_GATHER_INFO);
  script_copyright("Copyright (C) 2021 Greenbone Networks GmbH");
  script_family("Policy");
  script_dependencies("compliance_tests.nasl", "gb_huawei_vrp_network_device_consolidation.nasl");
  script_mandatory_keys("Compliance/Launch", "huawei/vrp/yunshan/detected");

  script_tag(name:"summary", value:"Checks if the key modulus of RSA and DSA is less than 2048, security risks exist.");

  exit(0);
}

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

cmd1 = "disp rsa key-pair brief";
cmd2 = "disp dsa key-pair brief";
cmd3 = "disp rsa local-key-pair public";
cmd4 = "disp dsa local-key-pair public";
cmd = cmd1 + '\n' + cmd2 + '\n' + cmd3 + '\n' + cmd4;
title = "The length of the host public key does not meet security requirements";
solution = "Run the rsa local-key-pair create or dsa local-key-pair create command to delete an insecure key.";
test_type = "SSH_Cmd";
default = "If the key modulus of RSA and DSA is less than 2048, security risks exist";

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( ! value1 = ssh_cmd( socket:sock, cmd:cmd1, return_errors:FALSE, pty:TRUE, nosh:TRUE, timeout:20,
                          retry:10, force_reconnect:TRUE, clear_buffer:TRUE ) ) {
    compliant = "incomplete";
    value = "error";
    comment = "Command '" + cmd1 + "' did not return anything";
  } else if( ! value2 = ssh_cmd( socket:sock, cmd:cmd2, return_errors:FALSE, pty:TRUE, nosh:TRUE, timeout:20,
                                 retry:10, force_reconnect:TRUE, clear_buffer:TRUE ) ) {
    compliant = "incomplete";
    value = "error";
    comment = "Command '" + cmd1 + "' did not return anything";
  } else if( ! value3 = ssh_cmd( socket:sock, cmd:cmd3, return_errors:FALSE, pty:TRUE, nosh:TRUE, timeout:20,
                                 retry:10, force_reconnect:TRUE, clear_buffer:TRUE ) ) {
    compliant = "incomplete";
    value = "error";
    comment = "Command '" + cmd1 + "' did not return anything";
  } else if( ! value4 = ssh_cmd( socket:sock, cmd:cmd4, return_errors:FALSE, pty:TRUE, nosh:TRUE, timeout:20,
                                 retry:10, force_reconnect:TRUE, clear_buffer:TRUE ) ) {
    compliant = "incomplete";
    value = "error";
    comment = "Command '" + cmd1 + "' did not return anything";
  } else if( value1 =~ "---- More ----" || value2 =~ "---- More ----" || value3 =~ "---- More ----" || value4 =~ "---- More ----" ) {
    # return was truncated
    compliant = "incomplete";
    value = "error";
    comment = "The return was truncated. Please set screen-length for this user-interface vty to 0.";
  } else {
    value = cmd1 + ':\n' + value1;
    value += '\n\n' + cmd2 + ':\n' + value2;
    value += '\n\n' + cmd3 + ':\n' + value3;
    value += '\n\n' + cmd4 + ':\n' + value4;

    rsa_key = eregmatch( string:value1, pattern:"Modulus:\s+([0-9]+)" );
    dsa_key = eregmatch( string:value2, pattern:"Modulus:\s+([0-9]+)" );
    rsa_local_key = eregmatch( string:value3, pattern:"modulus:\s+([0-9]+)" );
    dsa_local_key = eregmatch( string:value4, pattern:"modulus:\s+([0-9]+)" );

    if( rsa_key && int( rsa_key[1] ) < 2048 )
      compliant = "no";

    if( dsa_key && int( dsa_key[1] ) < 2048 )
      compliant = "no";

    if( rsa_local_key && int( rsa_local_key[1] ) < 2048 )
      compliant = "no";

    if( dsa_local_key && int( dsa_local_key[1] ) < 2048 )
      compliant = "no";

    if( ! compliant )
      compliant = "yes";
  }
}

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 );