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nessusThis script is Copyright (C) 2020-2022 and is owned by Tenable, Inc. or an Affiliate thereof.ORACLELINUX_ELSA-2020-2103.NASL
HistoryMay 14, 2020 - 12:00 a.m.

Oracle Linux 6 : kernel (ELSA-2020-2103)

2020-05-1400:00:00
This script is Copyright (C) 2020-2022 and is owned by Tenable, Inc. or an Affiliate thereof.
www.tenable.com
18

4.3 Medium

CVSS2

Attack Vector

NETWORK

Attack Complexity

MEDIUM

Authentication

NONE

Confidentiality Impact

NONE

Integrity Impact

NONE

Availability Impact

PARTIAL

AV:N/AC:M/Au:N/C:N/I:N/A:P

5.9 Medium

CVSS3

Attack Vector

NETWORK

Attack Complexity

HIGH

Privileges Required

NONE

User Interaction

NONE

Scope

UNCHANGED

Confidentiality Impact

NONE

Integrity Impact

NONE

Availability Impact

HIGH

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

0.008 Low

EPSS

Percentile

81.7%

The remote Oracle Linux 6 host has packages installed that are affected by a vulnerability as referenced in the ELSA-2020-2103 advisory.

  • A NULL pointer dereference flaw was found in the Linux kernel’s SELinux subsystem in versions before 5.7.
    This flaw occurs while importing the Commercial IP Security Option (CIPSO) protocol’s category bitmap into the SELinux extensible bitmap via the’ ebitmap_netlbl_import’ routine. While processing the CIPSO restricted bitmap tag in the ‘cipso_v4_parsetag_rbm’ routine, it sets the security attribute to indicate that the category bitmap is present, even if it has not been allocated. This issue leads to a NULL pointer dereference issue while importing the same category bitmap into SELinux. This flaw allows a remote network user to crash the system kernel, resulting in a denial of service. (CVE-2020-10711)

Note that Nessus has not tested for this issue but has instead relied only on the application’s self-reported version number.

#%NASL_MIN_LEVEL 70300
##
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Oracle Linux Security Advisory ELSA-2020-2103.
##

include('deprecated_nasl_level.inc');
include('compat.inc');

if (description)
{
  script_id(136602);
  script_version("1.5");
  script_set_attribute(attribute:"plugin_modification_date", value:"2022/01/26");

  script_cve_id("CVE-2020-10711");
  script_xref(name:"RHSA", value:"2020:2103");

  script_name(english:"Oracle Linux 6 : kernel (ELSA-2020-2103)");

  script_set_attribute(attribute:"synopsis", value:
"The remote Oracle Linux host is missing a security update.");
  script_set_attribute(attribute:"description", value:
"The remote Oracle Linux 6 host has packages installed that are affected by a vulnerability as referenced in the
ELSA-2020-2103 advisory.

  - A NULL pointer dereference flaw was found in the Linux kernel's SELinux subsystem in versions before 5.7.
    This flaw occurs while importing the Commercial IP Security Option (CIPSO) protocol's category bitmap into
    the SELinux extensible bitmap via the' ebitmap_netlbl_import' routine. While processing the CIPSO
    restricted bitmap tag in the 'cipso_v4_parsetag_rbm' routine, it sets the security attribute to indicate
    that the category bitmap is present, even if it has not been allocated. This issue leads to a NULL pointer
    dereference issue while importing the same category bitmap into SELinux. This flaw allows a remote network
    user to crash the system kernel, resulting in a denial of service. (CVE-2020-10711)

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version
number.");
  script_set_attribute(attribute:"see_also", value:"https://linux.oracle.com/errata/ELSA-2020-2103.html");
  script_set_attribute(attribute:"solution", value:
"Update the affected packages.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:M/Au:N/C:N/I:N/A:P");
  script_set_cvss_temporal_vector("CVSS2#E:U/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2020-10711");

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

  script_set_attribute(attribute:"vuln_publication_date", value:"2020/05/11");
  script_set_attribute(attribute:"patch_publication_date", value:"2020/05/13");
  script_set_attribute(attribute:"plugin_publication_date", value:"2020/05/14");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:oracle:linux:6");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:kernel");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:kernel-abi-whitelists");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:kernel-debug");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:kernel-debug-devel");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:kernel-devel");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:kernel-firmware");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:kernel-headers");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:perf");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:python-perf");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"Oracle Linux Local Security Checks");

  script_copyright(english:"This script is Copyright (C) 2020-2022 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("linux_alt_patch_detect.nasl", "ssh_get_info.nasl");
  script_require_keys("Host/OracleLinux", "Host/RedHat/release", "Host/RedHat/rpm-list", "Host/local_checks_enabled");

  exit(0);
}


include('audit.inc');
include('global_settings.inc');
include('ksplice.inc');
include('rpm.inc');

if (!get_kb_item('Host/local_checks_enabled')) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
if (!get_kb_item('Host/OracleLinux')) audit(AUDIT_OS_NOT, 'Oracle Linux');
var release = get_kb_item("Host/RedHat/release");
if (isnull(release) || !pregmatch(pattern: "Oracle (?:Linux Server|Enterprise Linux)", string:release)) audit(AUDIT_OS_NOT, 'Oracle Linux');
var os_ver = pregmatch(pattern: "Oracle (?:Linux Server|Enterprise Linux) .*release ([0-9]+(\.[0-9]+)?)", string:release);
if (isnull(os_ver)) audit(AUDIT_UNKNOWN_APP_VER, 'Oracle Linux');
var os_ver = os_ver[1];
if (! preg(pattern:"^6([^0-9]|$)", string:os_ver)) audit(AUDIT_OS_NOT, 'Oracle Linux 6', 'Oracle Linux ' + os_ver);

if (!get_kb_item('Host/RedHat/rpm-list')) audit(AUDIT_PACKAGE_LIST_MISSING);

var cpu = get_kb_item('Host/cpu');
if (isnull(cpu)) audit(AUDIT_UNKNOWN_ARCH);
if ('x86_64' >!< cpu && cpu !~ "^i[3-6]86$" && 'aarch64' >!< cpu) audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, 'Oracle Linux', cpu);

var machine_uptrack_level = get_one_kb_item('Host/uptrack-uname-r');
if (machine_uptrack_level)
{
  var trimmed_uptrack_level = ereg_replace(string:machine_uptrack_level, pattern:"\.(x86_64|i[3-6]86|aarch64)$", replace:'');
  var fixed_uptrack_levels = ['2.6.32-754.29.2.el6'];
  foreach var fixed_uptrack_level ( fixed_uptrack_levels ) {
    if (rpm_spec_vers_cmp(a:trimmed_uptrack_level, b:fixed_uptrack_level) >= 0)
    {
      audit(AUDIT_PATCH_INSTALLED, 'KSplice hotfix for ELSA-2020-2103');
    }
  }
  __rpm_report = 'Running KSplice level of ' + trimmed_uptrack_level + ' does not meet the minimum fixed level of ' + join(fixed_uptrack_levels, sep:' / ') + ' for this advisory.\n\n';
}

var kernel_major_minor = get_kb_item('Host/uname/major_minor');
if (empty_or_null(kernel_major_minor)) exit(1, 'Unable to determine kernel major-minor level.');
var expected_kernel_major_minor = '2.6';
if (kernel_major_minor != expected_kernel_major_minor)
  audit(AUDIT_OS_NOT, 'running kernel level ' + expected_kernel_major_minor + ', it is running kernel level ' + kernel_major_minor);

var pkgs = [
    {'reference':'kernel-2.6.32-754.29.2.el6', 'cpu':'i686', 'release':'6', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'kernel-2.6.32'},
    {'reference':'kernel-2.6.32-754.29.2.el6', 'cpu':'x86_64', 'release':'6', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'kernel-2.6.32'},
    {'reference':'kernel-abi-whitelists-2.6.32-754.29.2.el6', 'release':'6', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'kernel-abi-whitelists-2.6.32'},
    {'reference':'kernel-debug-2.6.32-754.29.2.el6', 'cpu':'i686', 'release':'6', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'kernel-debug-2.6.32'},
    {'reference':'kernel-debug-2.6.32-754.29.2.el6', 'cpu':'x86_64', 'release':'6', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'kernel-debug-2.6.32'},
    {'reference':'kernel-debug-devel-2.6.32-754.29.2.el6', 'cpu':'i686', 'release':'6', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'kernel-debug-devel-2.6.32'},
    {'reference':'kernel-debug-devel-2.6.32-754.29.2.el6', 'cpu':'x86_64', 'release':'6', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'kernel-debug-devel-2.6.32'},
    {'reference':'kernel-devel-2.6.32-754.29.2.el6', 'cpu':'i686', 'release':'6', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'kernel-devel-2.6.32'},
    {'reference':'kernel-devel-2.6.32-754.29.2.el6', 'cpu':'x86_64', 'release':'6', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'kernel-devel-2.6.32'},
    {'reference':'kernel-firmware-2.6.32-754.29.2.el6', 'release':'6', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'kernel-firmware-2.6.32'},
    {'reference':'kernel-headers-2.6.32-754.29.2.el6', 'cpu':'i686', 'release':'6', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'kernel-headers-2.6.32'},
    {'reference':'kernel-headers-2.6.32-754.29.2.el6', 'cpu':'x86_64', 'release':'6', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'kernel-headers-2.6.32'},
    {'reference':'perf-2.6.32-754.29.2.el6', 'cpu':'i686', 'release':'6', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'perf-2.6.32-754.29.2.el6', 'cpu':'x86_64', 'release':'6', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'python-perf-2.6.32-754.29.2.el6', 'cpu':'i686', 'release':'6', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'python-perf-2.6.32-754.29.2.el6', 'cpu':'x86_64', 'release':'6', 'rpm_spec_vers_cmp':TRUE}
];

var flag = 0;
foreach var package_array ( pkgs ) {
  var reference = NULL;
  var release = NULL;
  var sp = NULL;
  var cpu = NULL;
  var el_string = NULL;
  var rpm_spec_vers_cmp = NULL;
  var epoch = NULL;
  var allowmaj = NULL;
  var exists_check = NULL;
  if (!empty_or_null(package_array['reference'])) reference = package_array['reference'];
  if (!empty_or_null(package_array['release'])) release = 'EL' + package_array['release'];
  if (!empty_or_null(package_array['sp'])) sp = package_array['sp'];
  if (!empty_or_null(package_array['cpu'])) cpu = package_array['cpu'];
  if (!empty_or_null(package_array['el_string'])) el_string = package_array['el_string'];
  if (!empty_or_null(package_array['rpm_spec_vers_cmp'])) rpm_spec_vers_cmp = package_array['rpm_spec_vers_cmp'];
  if (!empty_or_null(package_array['epoch'])) epoch = package_array['epoch'];
  if (!empty_or_null(package_array['allowmaj'])) allowmaj = package_array['allowmaj'];
  if (!empty_or_null(package_array['exists_check'])) exists_check = package_array['exists_check'];
  if (reference && release) {
    if (exists_check) {
        if (rpm_exists(release:release, rpm:exists_check) && rpm_check(release:release, sp:sp, cpu:cpu, reference:reference, epoch:epoch, el_string:el_string, rpm_spec_vers_cmp:rpm_spec_vers_cmp, allowmaj:allowmaj)) flag++;
    } else {
        if (rpm_check(release:release, sp:sp, cpu:cpu, reference:reference, epoch:epoch, el_string:el_string, rpm_spec_vers_cmp:rpm_spec_vers_cmp, allowmaj:allowmaj)) flag++;
    }
  }
}

if (flag)
{
  security_report_v4(
      port       : 0,
      severity   : SECURITY_WARNING,
      extra      : rpm_report_get()
  );
  exit(0);
}
else
{
  var tested = pkg_tests_get();
  if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested);
  else audit(AUDIT_PACKAGE_NOT_INSTALLED, 'kernel / kernel-abi-whitelists / kernel-debug / etc');
}
VendorProductVersionCPE
oraclelinux6cpe:/o:oracle:linux:6
oraclelinuxkernelp-cpe:/a:oracle:linux:kernel
oraclelinuxkernel-abi-whitelistsp-cpe:/a:oracle:linux:kernel-abi-whitelists
oraclelinuxkernel-debugp-cpe:/a:oracle:linux:kernel-debug
oraclelinuxkernel-debug-develp-cpe:/a:oracle:linux:kernel-debug-devel
oraclelinuxkernel-develp-cpe:/a:oracle:linux:kernel-devel
oraclelinuxkernel-firmwarep-cpe:/a:oracle:linux:kernel-firmware
oraclelinuxkernel-headersp-cpe:/a:oracle:linux:kernel-headers
oraclelinuxperfp-cpe:/a:oracle:linux:perf
oraclelinuxpython-perfp-cpe:/a:oracle:linux:python-perf

4.3 Medium

CVSS2

Attack Vector

NETWORK

Attack Complexity

MEDIUM

Authentication

NONE

Confidentiality Impact

NONE

Integrity Impact

NONE

Availability Impact

PARTIAL

AV:N/AC:M/Au:N/C:N/I:N/A:P

5.9 Medium

CVSS3

Attack Vector

NETWORK

Attack Complexity

HIGH

Privileges Required

NONE

User Interaction

NONE

Scope

UNCHANGED

Confidentiality Impact

NONE

Integrity Impact

NONE

Availability Impact

HIGH

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

0.008 Low

EPSS

Percentile

81.7%