Fedora 39 : xen (2023-de338d9f37)

#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
##
# The descriptive text and package checks in this plugin were
# extracted from Fedora Security Advisory FEDORA-2023-de338d9f37
#

include('compat.inc');

if (description)
{
  script_id(185217);
  script_version("1.4");
  script_set_attribute(attribute:"plugin_modification_date", value:"2024/04/29");

  script_cve_id(
    "CVE-2023-34323",
    "CVE-2023-34325",
    "CVE-2023-34326",
    "CVE-2023-34327",
    "CVE-2023-34328"
  );
  script_xref(name:"FEDORA", value:"2023-de338d9f37");
  script_xref(name:"IAVB", value:"2023-B-0081-S");

  script_name(english:"Fedora 39 : xen (2023-de338d9f37)");

  script_set_attribute(attribute:"synopsis", value:
"The remote Fedora host is missing one or more security updates.");
  script_set_attribute(attribute:"description", value:
"The remote Fedora 39 host has a package installed that is affected by multiple vulnerabilities as referenced in the
FEDORA-2023-de338d9f37 advisory.

  - When a transaction is committed, C Xenstored will first check the quota is correct before attempting to
    commit any nodes. It would be possible that accounting is temporarily negative if a node has been removed
    outside of the transaction. Unfortunately, some versions of C Xenstored are assuming that the quota cannot
    be negative and are using assert() to confirm it. This will lead to C Xenstored crash when tools are built
    without -DNDEBUG (this is the default). (CVE-2023-34323)

  - [This CNA information record relates to multiple CVEs; the text explains which aspects/vulnerabilities
    correspond to which CVE.] libfsimage contains parsing code for several filesystems, most of them based on
    grub-legacy code. libfsimage is used by pygrub to inspect guest disks. Pygrub runs as the same user as the
    toolstack (root in a priviledged domain). At least one issue has been reported to the Xen Security Team
    that allows an attacker to trigger a stack buffer overflow in libfsimage. After further analisys the Xen
    Security Team is no longer confident in the suitability of libfsimage when run against guest controlled
    input with super user priviledges. In order to not affect current deployments that rely on pygrub patches
    are provided in the resolution section of the advisory that allow running pygrub in deprivileged mode.
    CVE-2023-4949 refers to the original issue in the upstream grub project (An attacker with local access to
    a system (either through a disk or external drive) can present a modified XFS partition to grub-legacy in
    such a way to exploit a memory corruption in grub's XFS file system implementation.) CVE-2023-34325
    refers specifically to the vulnerabilities in Xen's copy of libfsimage, which is decended from a very old
    version of grub. (CVE-2023-34325)

  - The caching invalidation guidelines from the AMD-Vi specification (48882Rev 3.07-PUBOct 2022) is
    incorrect on some hardware, as devices will malfunction (see stale DMA mappings) if some fields of the DTE
    are updated but the IOMMU TLB is not flushed. Such stale DMA mappings can point to memory ranges not owned
    by the guest, thus allowing access to unindented memory regions. (CVE-2023-34326)

  - [This CNA information record relates to multiple CVEs; the text explains which aspects/vulnerabilities
    correspond to which CVE.] AMD CPUs since ~2014 have extensions to normal x86 debugging functionality. Xen
    supports guests using these extensions. Unfortunately there are errors in Xen's handling of the guest
    state, leading to denials of service. 1) CVE-2023-34327 - An HVM vCPU can end up operating in the context
    of a previous vCPUs debug mask state. 2) CVE-2023-34328 - A PV vCPU can place a breakpoint over the live
    GDT. This allows the PV vCPU to exploit XSA-156 / CVE-2015-8104 and lock up the CPU entirely.
    (CVE-2023-34327, CVE-2023-34328)

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version
number.");
  script_set_attribute(attribute:"see_also", value:"https://bodhi.fedoraproject.org/updates/FEDORA-2023-de338d9f37");
  script_set_attribute(attribute:"solution", value:
"Update the affected xen package.");
  script_set_cvss_base_vector("CVSS2#AV:L/AC:L/Au:S/C:C/I:C/A:C");
  script_set_cvss_temporal_vector("CVSS2#E:U/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/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-2023-34326");

  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:"2023/10/10");
  script_set_attribute(attribute:"patch_publication_date", value:"2023/10/10");
  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:"cpe:/o:fedoraproject:fedora:39");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:fedoraproject:fedora:xen");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_set_attribute(attribute:"stig_severity", value:"I");
  script_end_attributes();

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

  script_copyright(english:"This script is Copyright (C) 2023-2024 and is owned by Tenable, Inc. or an Affiliate thereof.");

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

  exit(0);
}


include('rpm.inc');

if (!get_kb_item('Host/local_checks_enabled')) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
var os_release = get_kb_item('Host/RedHat/release');
if (isnull(os_release) || 'Fedora' >!< os_release) audit(AUDIT_OS_NOT, 'Fedora');
var os_ver = pregmatch(pattern: "Fedora.*release ([0-9]+)", string:os_release);
if (isnull(os_ver)) audit(AUDIT_UNKNOWN_APP_VER, 'Fedora');
os_ver = os_ver[1];
if (! preg(pattern:"^39([^0-9]|$)", string:os_ver)) audit(AUDIT_OS_NOT, 'Fedora 39', 'Fedora ' + 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$" && 's390' >!< cpu && 'aarch64' >!< cpu) audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, 'Fedora', cpu);

var pkgs = [
    {'reference':'xen-4.17.2-4.fc39', 'release':'FC39', 'rpm_spec_vers_cmp':TRUE}
];

var flag = 0;
foreach 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;
  if (!empty_or_null(package_array['reference'])) reference = package_array['reference'];
  if (!empty_or_null(package_array['release'])) _release = 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 (reference && _release) {
    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, 'xen');
}