F5 Networks BIG-IP : F5 IPsec vulnerability (K76610106)

#
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from F5 Networks BIG-IP Solution K76610106.
#
# The text description of this plugin is (C) F5 Networks.
#

include('compat.inc');

if (description)
{
  script_id(142046);
  script_version("1.4");
  script_set_attribute(attribute:"plugin_modification_date", value:"2023/11/03");

  script_cve_id("CVE-2020-5938");

  script_name(english:"F5 Networks BIG-IP : F5 IPsec vulnerability (K76610106)");

  script_set_attribute(attribute:"synopsis", value:
"The remote device is missing a vendor-supplied security patch.");
  script_set_attribute(attribute:"description", value:
"When negotiating IPsec tunnels with configured, authenticated peers,
the peer may negotiate a different key length than the BIG-IP
configuration would otherwise allow.(CVE-2020-5938)

Impact

IPsec connections can be created with a different key length than
specified in the BIG-IP configuration, potentially leading to
lesser-than-configured encryption strength for the connection.

For example, if the BIG-IP system was configured for AES256
encryption, the Security Associationcould be successfully negotiated
using AES128 encryption. It is not possible to change the algorithm,
or to disable encryption, but it is possible for peers to modify the
key length and still successfully negotiate an IPsec connection.");
  script_set_attribute(attribute:"see_also", value:"https://my.f5.com/manage/s/article/K76610106");
  script_set_attribute(attribute:"solution", value:
"Upgrade to one of the non-vulnerable versions listed in the F5 Solution K76610106.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:S/C:P/I:N/A:N");
  script_set_cvss_temporal_vector("CVSS2#E:U/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2020-5938");

  script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available");

  script_set_attribute(attribute:"vuln_publication_date", value:"2020/10/29");
  script_set_attribute(attribute:"patch_publication_date", value:"2020/10/28");
  script_set_attribute(attribute:"plugin_publication_date", value:"2020/10/29");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/a:f5:big-ip_access_policy_manager");
  script_set_attribute(attribute:"cpe", value:"cpe:/a:f5:big-ip_advanced_firewall_manager");
  script_set_attribute(attribute:"cpe", value:"cpe:/a:f5:big-ip_application_acceleration_manager");
  script_set_attribute(attribute:"cpe", value:"cpe:/a:f5:big-ip_application_security_manager");
  script_set_attribute(attribute:"cpe", value:"cpe:/a:f5:big-ip_application_visibility_and_reporting");
  script_set_attribute(attribute:"cpe", value:"cpe:/a:f5:big-ip_domain_name_system");
  script_set_attribute(attribute:"cpe", value:"cpe:/a:f5:big-ip_global_traffic_manager");
  script_set_attribute(attribute:"cpe", value:"cpe:/a:f5:big-ip_link_controller");
  script_set_attribute(attribute:"cpe", value:"cpe:/a:f5:big-ip_local_traffic_manager");
  script_set_attribute(attribute:"cpe", value:"cpe:/a:f5:big-ip_policy_enforcement_manager");
  script_set_attribute(attribute:"cpe", value:"cpe:/h:f5:big-ip");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"F5 Networks Local Security Checks");

  script_copyright(english:"This script is Copyright (C) 2020-2023 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("f5_bigip_detect.nbin");
  script_require_keys("Host/local_checks_enabled", "Host/BIG-IP/hotfix", "Host/BIG-IP/modules", "Host/BIG-IP/version");

  exit(0);
}


include('f5_func.inc');

if ( ! get_kb_item('Host/local_checks_enabled') ) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
var version = get_kb_item('Host/BIG-IP/version');
if ( ! version ) audit(AUDIT_OS_NOT, 'F5 Networks BIG-IP');
if ( isnull(get_kb_item('Host/BIG-IP/hotfix')) ) audit(AUDIT_KB_MISSING, 'Host/BIG-IP/hotfix');
if ( ! get_kb_item('Host/BIG-IP/modules') ) audit(AUDIT_KB_MISSING, 'Host/BIG-IP/modules');

var sol = 'K76610106';
var vmatrix = {
  'AFM': {
    'affected': [
      '13.1.0-13.1.3','12.1.0-12.1.5','11.6.1-11.6.5'
    ],
    'unaffected': [
      '14.1.0'
    ],
  },
  'AM': {
    'affected': [
      '13.1.0-13.1.3','12.1.0-12.1.5','11.6.1-11.6.5'
    ],
    'unaffected': [
      '14.1.0'
    ],
  },
  'APM': {
    'affected': [
      '13.1.0-13.1.3','12.1.0-12.1.5','11.6.1-11.6.5'
    ],
    'unaffected': [
      '14.1.0'
    ],
  },
  'ASM': {
    'affected': [
      '13.1.0-13.1.3','12.1.0-12.1.5','11.6.1-11.6.5'
    ],
    'unaffected': [
      '14.1.0'
    ],
  },
  'AVR': {
    'affected': [
      '13.1.0-13.1.3','12.1.0-12.1.5','11.6.1-11.6.5'
    ],
    'unaffected': [
      '14.1.0'
    ],
  },
  'DNS': {
    'affected': [
      '13.1.0-13.1.3','12.1.0-12.1.5','11.6.1-11.6.5'
    ],
    'unaffected': [
      '14.1.0'
    ],
  },
  'GTM': {
    'affected': [
      '13.1.0-13.1.3','12.1.0-12.1.5','11.6.1-11.6.5'
    ],
    'unaffected': [
      '14.1.0'
    ],
  },
  'LC': {
    'affected': [
      '13.1.0-13.1.3','12.1.0-12.1.5','11.6.1-11.6.5'
    ],
    'unaffected': [
      '14.1.0'
    ],
  },
  'LTM': {
    'affected': [
      '13.1.0-13.1.3','12.1.0-12.1.5','11.6.1-11.6.5'
    ],
    'unaffected': [
      '14.1.0'
    ],
  },
  'PEM': {
    'affected': [
      '13.1.0-13.1.3','12.1.0-12.1.5','11.6.1-11.6.5'
    ],
    'unaffected': [
      '14.1.0'
    ],
  }
};

if (bigip_is_affected(vmatrix:vmatrix, sol:sol))
{
  var extra = NULL;
  if (report_verbosity > 0) extra = bigip_report_get();
  security_report_v4(
      port       : 0,
      severity   : SECURITY_WARNING,
      extra      : extra
  );
}
else
{
  var tested = bigip_get_tested_modules();
  var audit_extra = 'For BIG-IP module(s) ' + tested + ',';
  if (tested) audit(AUDIT_INST_VER_NOT_VULN, audit_extra, version);
  else audit(AUDIT_HOST_NOT, 'running any of the affected modules');
}