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nessusThis script is Copyright (C) 2023 and is owned by Tenable, Inc. or an Affiliate thereof.ROCKY_LINUX_RLSA-2021-3547.NASL
HistoryNov 07, 2023 - 12:00 a.m.

Rocky Linux 8 : kernel-rt (RLSA-2021:3547)

2023-11-0700:00:00
This script is Copyright (C) 2023 and is owned by Tenable, Inc. or an Affiliate thereof.
www.tenable.com
1
rocky linux 8
kernel-rt
vulnerability
amd
svm
nested virtualization
cve-2021-3653

6.3 Medium

AI Score

Confidence

Low

The remote Rocky Linux 8 host has packages installed that are affected by a vulnerability as referenced in the RLSA-2021:3547 advisory.

  • A flaw was found in the KVM’s AMD code for supporting SVM nested virtualization. The flaw occurs when processing the VMCB (virtual machine control block) provided by the L1 guest to spawn/handle a nested guest (L2). Due to improper validation of the int_ctl field, this issue could allow a malicious L1 to enable AVIC support (Advanced Virtual Interrupt Controller) for the L2 guest. As a result, the L2 guest would be allowed to read/write physical pages of the host, resulting in a crash of the entire system, leak of sensitive data or potential guest-to-host escape. This flaw affects Linux kernel versions prior to 5.14-rc7. (CVE-2021-3653)

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 80900
##
# (C) Tenable, Inc.
#
# The package checks in this plugin were extracted from
# Rocky Linux Security Advisory RLSA-2021:3547.
##

include('compat.inc');

if (description)
{
  script_id(184945);
  script_version("1.0");
  script_set_attribute(attribute:"plugin_modification_date", value:"2023/11/07");

  script_cve_id("CVE-2021-3653");
  script_xref(name:"RLSA", value:"2021:3547");

  script_name(english:"Rocky Linux 8 : kernel-rt (RLSA-2021:3547)");

  script_set_attribute(attribute:"synopsis", value:
"The remote Rocky Linux host is missing a security update.");
  script_set_attribute(attribute:"description", value:
"The remote Rocky Linux 8 host has packages installed that are affected by a vulnerability as referenced in the
RLSA-2021:3547 advisory.

  - A flaw was found in the KVM's AMD code for supporting SVM nested virtualization. The flaw occurs when
    processing the VMCB (virtual machine control block) provided by the L1 guest to spawn/handle a nested
    guest (L2). Due to improper validation of the int_ctl field, this issue could allow a malicious L1 to
    enable AVIC support (Advanced Virtual Interrupt Controller) for the L2 guest. As a result, the L2 guest
    would be allowed to read/write physical pages of the host, resulting in a crash of the entire system, leak
    of sensitive data or potential guest-to-host escape. This flaw affects Linux kernel versions prior to
    5.14-rc7. (CVE-2021-3653)

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://errata.rockylinux.org/RLSA-2021:3547");
  script_set_attribute(attribute:"see_also", value:"https://bugzilla.redhat.com/show_bug.cgi?id=1983686");
  script_set_attribute(attribute:"solution", value:
"Update the affected packages.");
  script_set_cvss_base_vector("CVSS2#AV:L/AC:L/Au:N/C:P/I:P/A:C");
  script_set_cvss_temporal_vector("CVSS2#E:POC/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:P/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2021-3653");

  script_set_attribute(attribute:"exploitability_ease", value:"Exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"true");

  script_set_attribute(attribute:"vuln_publication_date", value:"2021/09/15");
  script_set_attribute(attribute:"patch_publication_date", value:"2021/09/15");
  script_set_attribute(attribute:"plugin_publication_date", value:"2023/11/07");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:rocky:linux:kernel-rt");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:rocky:linux:kernel-rt-core");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:rocky:linux:kernel-rt-debug");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:rocky:linux:kernel-rt-debug-core");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:rocky:linux:kernel-rt-debug-debuginfo");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:rocky:linux:kernel-rt-debug-devel");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:rocky:linux:kernel-rt-debug-modules");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:rocky:linux:kernel-rt-debug-modules-extra");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:rocky:linux:kernel-rt-debuginfo");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:rocky:linux:kernel-rt-debuginfo-common-x86_64");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:rocky:linux:kernel-rt-devel");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:rocky:linux:kernel-rt-modules");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:rocky:linux:kernel-rt-modules-extra");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:rocky:linux:8");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

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

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

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

  exit(0);
}


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

if (!get_kb_item('Host/local_checks_enabled')) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
var os_release = get_kb_item('Host/RockyLinux/release');
if (isnull(os_release) || 'Rocky Linux' >!< os_release) audit(AUDIT_OS_NOT, 'Rocky Linux');
var os_ver = pregmatch(pattern: "Rocky(?: Linux)? release ([0-9]+(\.[0-9]+)?)", string:os_release);
if (isnull(os_ver)) audit(AUDIT_UNKNOWN_APP_VER, 'Rocky Linux');
os_ver = os_ver[1];
if (! preg(pattern:"^8([^0-9]|$)", string:os_ver)) audit(AUDIT_OS_NOT, 'Rocky Linux 8.x', 'Rocky Linux ' + os_ver);

if (!get_kb_item('Host/RockyLinux/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$" && 's390' >!< cpu && 'aarch64' >!< cpu) audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, 'Rocky Linux', cpu);

if (get_one_kb_item('Host/ksplice/kernel-cves'))
{
  rm_kb_item(name:'Host/uptrack-uname-r');
  var cve_list = make_list('CVE-2021-3653');
  if (ksplice_cves_check(cve_list))
  {
    audit(AUDIT_PATCH_INSTALLED, 'KSplice hotfix for RLSA-2021:3547');
  }
  else
  {
    __rpm_report = ksplice_reporting_text();
  }
}

var pkgs = [
    {'reference':'kernel-rt-4.18.0-305.19.1.rt7.91.el8_4', 'cpu':'x86_64', 'release':'8', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-rt-core-4.18.0-305.19.1.rt7.91.el8_4', 'cpu':'x86_64', 'release':'8', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-rt-debug-4.18.0-305.19.1.rt7.91.el8_4', 'cpu':'x86_64', 'release':'8', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-rt-debug-core-4.18.0-305.19.1.rt7.91.el8_4', 'cpu':'x86_64', 'release':'8', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-rt-debug-debuginfo-4.18.0-305.19.1.rt7.91.el8_4', 'cpu':'x86_64', 'release':'8', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-rt-debug-devel-4.18.0-305.19.1.rt7.91.el8_4', 'cpu':'x86_64', 'release':'8', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-rt-debug-modules-4.18.0-305.19.1.rt7.91.el8_4', 'cpu':'x86_64', 'release':'8', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-rt-debug-modules-extra-4.18.0-305.19.1.rt7.91.el8_4', 'cpu':'x86_64', 'release':'8', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-rt-debuginfo-4.18.0-305.19.1.rt7.91.el8_4', 'cpu':'x86_64', 'release':'8', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-rt-debuginfo-common-x86_64-4.18.0-305.19.1.rt7.91.el8_4', 'cpu':'x86_64', 'release':'8', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-rt-devel-4.18.0-305.19.1.rt7.91.el8_4', 'cpu':'x86_64', 'release':'8', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-rt-modules-4.18.0-305.19.1.rt7.91.el8_4', 'cpu':'x86_64', 'release':'8', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-rt-modules-extra-4.18.0-305.19.1.rt7.91.el8_4', 'cpu':'x86_64', 'release':'8', '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 = 'Rocky-' + 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 && (!exists_check || rpm_exists(release:_release, rpm:exists_check))) {
    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-rt / kernel-rt-core / kernel-rt-debug / kernel-rt-debug-core / etc');
}
VendorProductVersionCPE
rockylinuxkernel-rtp-cpe:/a:rocky:linux:kernel-rt
rockylinuxkernel-rt-corep-cpe:/a:rocky:linux:kernel-rt-core
rockylinuxkernel-rt-debugp-cpe:/a:rocky:linux:kernel-rt-debug
rockylinuxkernel-rt-debug-corep-cpe:/a:rocky:linux:kernel-rt-debug-core
rockylinuxkernel-rt-debug-debuginfop-cpe:/a:rocky:linux:kernel-rt-debug-debuginfo
rockylinuxkernel-rt-debug-develp-cpe:/a:rocky:linux:kernel-rt-debug-devel
rockylinuxkernel-rt-debug-modulesp-cpe:/a:rocky:linux:kernel-rt-debug-modules
rockylinuxkernel-rt-debug-modules-extrap-cpe:/a:rocky:linux:kernel-rt-debug-modules-extra
rockylinuxkernel-rt-debuginfop-cpe:/a:rocky:linux:kernel-rt-debuginfo
rockylinuxkernel-rt-debuginfo-common-x86_64p-cpe:/a:rocky:linux:kernel-rt-debuginfo-common-x86_64
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