Cisco NX-OS: GNU Bash Environment Variable Command Injection Vulnerability

# Copyright (C) 2016 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.

CPE = "cpe:/o:cisco:nx-os";

if (description)
{
  script_oid("1.3.6.1.4.1.25623.1.0.105693");
  script_version("2022-12-26T10:12:01+0000");
  script_tag(name:"last_modification", value:"2022-12-26 10:12:01 +0000 (Mon, 26 Dec 2022)");
  script_tag(name:"creation_date", value:"2016-05-12 15:45:58 +0200 (Thu, 12 May 2016)");
  script_tag(name:"cvss_base", value:"10.0");
  script_tag(name:"cvss_base_vector", value:"AV:N/AC:L/Au:N/C:C/I:C/A:C");
  script_tag(name:"severity_vector", value:"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H");
  script_tag(name:"severity_origin", value:"NVD");
  script_tag(name:"severity_date", value:"2021-02-01 21:38:00 +0000 (Mon, 01 Feb 2021)");

  script_xref(name:"CISA", value:"Known Exploited Vulnerability (KEV) catalog");
  script_xref(name:"URL", value:"https://www.cisa.gov/known-exploited-vulnerabilities-catalog");

  script_cve_id("CVE-2014-6271");

  script_tag(name:"qod_type", value:"remote_banner");

  script_tag(name:"solution_type", value:"VendorFix");

  script_name("Cisco NX-OS: GNU Bash Environment Variable Command Injection Vulnerability");

  script_category(ACT_GATHER_INFO);

  script_copyright("Copyright (C) 2016 Greenbone Networks GmbH");
  script_family("CISCO");
  script_dependencies("gb_cisco_nx_os_consolidation.nasl");
  script_mandatory_keys("cisco/nx_os/detected", "cisco/nx_os/device", "cisco/nx_os/model");

  script_tag(name:"summary", value:"On September 24, 2014, a vulnerability in the Bash shell was
  publicly announced. The vulnerability is related to the way in which shell functions are passed
  though environment variables. The vulnerability may allow an attacker to inject commands into a
  Bash shell, depending on how the shell is invoked. The Bash shell may be invoked by a number of
  processes including, but not limited to, telnet, SSH, DHCP, and scripts hosted on web servers.");

  script_tag(name:"vuldetect", value:"Checks if a vulnerable version is present on the target host.");

  script_tag(name:"insight", value:"All versions of GNU Bash starting with version 1.14 are
  affected by this vulnerability and the specific impact is determined by the characteristics of
  the process using the Bash shell. In the worst case, an unauthenticated remote attacker would be
  able to execute commands on an affected server. However, in most cases involving Cisco products,
  authentication is required before exploitation could be attempted.");

  script_tag(name:"solution", value:"See the referenced vendor advisory for a solution.");

  script_xref(name:"URL", value:"https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20140926-bash");
  script_xref(name:"URL", value:"http://tools.cisco.com/security/center/viewAMBAlert.x?alertId=35836");
  script_xref(name:"URL", value:"http://tools.cisco.com/security/center/viewAlert.x?alertId=35880");
  script_xref(name:"URL", value:"http://tools.cisco.com/security/center/viewAlert.x?alertId=35845");
  script_xref(name:"URL", value:"http://tools.cisco.com/security/center/viewAlert.x?alertId=35879");
  script_xref(name:"URL", value:"http://tools.cisco.com/security/center/viewAlert.x?alertId=35860");
  script_xref(name:"URL", value:"http://tools.cisco.com/security/center/viewAlert.x?alertId=35861");
  script_xref(name:"URL", value:"http://tools.cisco.com/security/center/viewAlert.x?alertId=35816");

  exit(0);
}

include("host_details.inc");
include("version_func.inc");

if( ! device = get_kb_item( "cisco/nx_os/device" ) )
  exit( 0 );

if( "Nexus" >!< device )
  exit( 0 );

if ( ! nx_model = get_kb_item( "cisco/nx_os/model" ) )
  exit( 0 );

if( ! version = get_app_version( cpe:CPE, nofork:TRUE ) )
  exit( 0 );

if( "1000V" >< nx_model ) {
  affected = make_list(
    "4.0(4)SV1(1)",
    "4.0(4)SV1(2)",
    "4.0(4)SV1(3)",
    "4.0(4)SV1(3a)",
    "4.0(4)SV1(3b)",
    "4.0(4)SV1(3c)",
    "4.0(4)SV1(3d)",
    "4.2(1)SV1(4)",
    "4.2(1)SV1(4a)",
    "4.2(1)SV1(4b)",
    "4.2(1)SV1(5.1)",
    "4.2(1)SV1(5.1a)",
    "4.2(1)SV1(5.2)",
    "4.2(1)SV1(5.2b)",
    "4.2(1)SV2(1.1)",
    "4.2(1)SV2(1.1a)",
    "4.2(1)SV2(2.1)",
    "4.2(1)SV2(2.1a)"
  );
}

if( nx_model =~ "^C?3[0-9]+" ) {
  affected = make_list(
    "5.0(3)U1(1)",
    "5.0(3)U1(1a)",
    "5.0(3)U1(1b)",
    "5.0(3)U1(1d)",
    "5.0(3)U1(2)",
    "5.0(3)U1(2a)",
    "5.0(3)U2(1)",
    "5.0(3)U2(2)",
    "5.0(3)U2(2a)",
    "5.0(3)U2(2b)",
    "5.0(3)U2(2c)",
    "5.0(3)U2(2d)",
    "5.0(3)U3(1)",
    "5.0(3)U3(2)",
    "5.0(3)U3(2a)",
    "5.0(3)U3(2b)",
    "5.0(3)U4(1)",
    "5.0(3)U5(1)",
    "5.0(3)U5(1a)",
    "5.0(3)U5(1b)",
    "5.0(3)U5(1c)",
    "5.0(3)U5(1d)",
    "5.0(3)U5(1e)",
    "5.0(3)U5(1f)",
    "5.0(3)U5(1g)",
    "5.0(3)U5(1h)",
    "6.0(2)U1(1)",
    "6.0(2)U1(1a)",
    "6.0(2)U1(2)",
    "6.0(2)U1(3)",
    "6.0(2)U4(1)"
  );
}

if( nx_model =~ "^C?4[0-9]+" ) {
  affected = make_list(
    "4.1(2)E1(1)",
    "4.1(2)E1(1b)",
    "4.1(2)E1(1d)",
    "4.1(2)E1(1e)",
    "4.1(2)E1(1f)",
    "4.1(2)E1(1g)",
    "4.1(2)E1(1h)",
    "4.1(2)E1(1i)",
    "4.1(2)E1(1j)"
  );
}

if( nx_model =~ "^C?5[0-9]+" ) {
  affected = make_list(
    "4.0(0)N1(1a)",
    "4.0(0)N1(2)",
    "4.0(0)N1(2a)",
    "4.0(1a)N1(1)",
    "4.0(1a)N1(1a)",
    "4.0(1a)N2(1)",
    "4.0(1a)N2(1a)",
    "4.1(3)N1(1)",
    "4.1(3)N1(1a)",
    "4.1(3)N2(1)",
    "4.1(3)N2(1a)",
    "4.2(1)N1(1)",
    "4.2(1)N2(1)",
    "4.2(1)N2(1a)",
    "5.0(2)N1(1)",
    "5.0(2)N2(1)",
    "5.0(2)N2(1a)",
    "5.0(3)N1(1c)",
    "5.0(3)N2(1)",
    "5.0(3)N2(2)",
    "5.0(3)N2(2a)",
    "5.0(3)N2(2b)",
    "5.1(3)N1(1)",
    "5.1(3)N1(1a)",
    "5.1(3)N2(1)",
    "5.1(3)N2(1a)",
    "5.1(3)N2(1b)",
    "5.1(3)N2(1c)",
    "5.2(1)N1(1)",
    "5.2(1)N1(1a)",
    "5.2(1)N1(1b)",
    "5.2(1)N1(2)",
    "5.2(1)N1(2a)",
    "5.2(1)N1(3)",
    "5.2(1)N1(4)",
    "5.2(1)N1(5)",
    "5.2(1)N1(6)",
    "5.2(1)N1(7)",
    "5.2(1)N1(8)",
    "5.2(1)N1(8a)",
    "6.0(2)N1(1)",
    "6.0(2)N1(2)",
    "6.0(2)N1(2a)",
    "6.0(2)N2(1)",
    "6.0(2)N2(1b)",
    "6.0(2)N2(2)",
    "6.0(2)N2(3)",
    "6.0(2)N2(4)",
    "6.0(2)N2(5)",
    "7.0(0)N1(1)",
    "7.0(1)N1(1)",
    "7.0(2)N1(1)",
    "7.0(3)N1(1)"
  );
}

if( nx_model =~ "^C?6[0-9]+" ) {
  affected = make_list(
    "6.0(2)N1(2)",
    "6.0(2)N1(2a)",
    "6.0(2)N2(1)",
    "6.0(2)N2(1b)",
    "6.0(2)N2(2)",
    "6.0(2)N2(3)",
    "6.0(2)N2(4)",
    "6.0(2)N2(5)",
    "7.0(0)N1(1)",
    "7.0(1)N1(1)",
    "7.0(2)N1(1)",
    "7.0(3)N1(1)"
  );
}

if( nx_model =~ "^C?7[0-9]+" ) {
  affected = make_list(
    "4.1.(2)",
    "4.1.(3)",
    "4.1.(4)",
    "4.1.(5)",
    "4.2(3)",
    "4.2(4)",
    "4.2(6)",
    "4.2(8)",
    "4.2.(2a)",
    "5.0(2a)",
    "5.0(3)",
    "5.0(5)",
    "5.1(1)",
    "5.1(1a)",
    "5.1(3)",
    "5.1(4)",
    "5.1(5)",
    "5.1(6)",
    "5.2(1)",
    "5.2(3a)",
    "5.2(4)",
    "5.2(5)",
    "5.2(7)",
    "5.2(9)",
    "6.0(1)",
    "6.0(2)",
    "6.0(3)",
    "6.0(4)",
    "6.1(1)",
    "6.1(2)",
    "6.1(3)",
    "6.1(4)",
    "6.1(4a)",
    "6.2(2)",
    "6.2(2a)",
    "6.2(6)"
  );
}

if( nx_model =~ "^C?9[0-9]{3}" ) {
  affected = make_list(
    "11.0(1b)",
    "11.0(1c)",
    "6.1(2)I2(1)",
    "6.1(2)I2(2)",
    "6.1(2)I2(2a)",
    "6.1(2)I2(2b)",
    "6.1(2)I2(3)"
  );
}

foreach af ( affected ) {
  if( version == af ) {
    report = report_fixed_ver( installed_version:version, fixed_version:"See advisory" );
    security_message( port:0, data:report );
    exit( 0 );
  }
}

exit( 99 );