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nessusThis script is Copyright (C) 2021-2024 and is owned by Tenable, Inc. or an Affiliate thereof.FEDORA_2021-7066B95C99.NASL
HistoryJan 25, 2021 - 12:00 a.m.

Fedora 33 : sddm (2021-7066b95c99)

2021-01-2500:00:00
This script is Copyright (C) 2021-2024 and is owned by Tenable, Inc. or an Affiliate thereof.
www.tenable.com
25
fedora 33
sddm vulnerability
race condition

CVSS2

3.3

Attack Vector

LOCAL

Attack Complexity

MEDIUM

Authentication

NONE

Confidentiality Impact

PARTIAL

Integrity Impact

PARTIAL

Availability Impact

NONE

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

CVSS3

6.3

Attack Vector

LOCAL

Attack Complexity

HIGH

Privileges Required

LOW

User Interaction

NONE

Scope

UNCHANGED

Confidentiality Impact

HIGH

Integrity Impact

HIGH

Availability Impact

NONE

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

AI Score

6.1

Confidence

High

EPSS

0

Percentile

5.1%

The remote Fedora 33 host has a package installed that is affected by a vulnerability as referenced in the FEDORA-2021-7066b95c99 advisory.

  • An issue was discovered in SDDM before 0.19.0. It incorrectly starts the X server in a way that - for a short time period - allows local unprivileged users to create a connection to the X server without providing proper authentication. A local attacker can thus access X server display contents and, for example, intercept keystrokes or access the clipboard. This is caused by a race condition during Xauthority file creation. (CVE-2020-28049)

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

##
# (C) Tenable Network Security, Inc.
##
# The descriptive text and package checks in this plugin were
# extracted from Fedora Security Advisory FEDORA-2021-7066b95c99
#

include('compat.inc');

if (description)
{
  script_id(145315);
  script_version("1.4");
  script_set_attribute(attribute:"plugin_modification_date", value:"2024/01/26");

  script_cve_id("CVE-2020-28049");
  script_xref(name:"FEDORA", value:"2021-7066b95c99");

  script_name(english:"Fedora 33 : sddm (2021-7066b95c99)");

  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 33 host has a package installed that is affected by a vulnerability as referenced in the
FEDORA-2021-7066b95c99 advisory.

  - An issue was discovered in SDDM before 0.19.0. It incorrectly starts the X server in a way that - for a
    short time period - allows local unprivileged users to create a connection to the X server without
    providing proper authentication. A local attacker can thus access X server display contents and, for
    example, intercept keystrokes or access the clipboard. This is caused by a race condition during
    Xauthority file creation. (CVE-2020-28049)

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://bodhi.fedoraproject.org/updates/FEDORA-2021-7066b95c99");
  script_set_attribute(attribute:"solution", value:
"Update the affected sddm package.");
  script_set_cvss_base_vector("CVSS2#AV:L/AC:M/Au:N/C:P/I:P/A:N");
  script_set_cvss_temporal_vector("CVSS2#E:POC/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:P/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2020-28049");

  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:"2020/11/04");
  script_set_attribute(attribute:"patch_publication_date", value:"2021/01/23");
  script_set_attribute(attribute:"plugin_publication_date", value:"2021/01/25");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:fedoraproject:fedora:33");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:fedoraproject:fedora:sddm");
  script_end_attributes();

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

  script_copyright(english:"This script is Copyright (C) 2021-2024 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('audit.inc');
include('global_settings.inc');
include('rpm.inc');

if (!get_kb_item('Host/local_checks_enabled')) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
release = get_kb_item('Host/RedHat/release');
if (isnull(release) || 'Fedora' >!< release) audit(AUDIT_OS_NOT, 'Fedora');
os_ver = pregmatch(pattern: "Fedora.*release ([0-9]+)", string:release);
if (isnull(os_ver)) audit(AUDIT_UNKNOWN_APP_VER, 'Fedora');
os_ver = os_ver[1];
if (! preg(pattern:"^33([^0-9]|$)", string:os_ver)) audit(AUDIT_OS_NOT, 'Fedora 33', 'Fedora ' + os_ver);

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

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);

pkgs = [
    {'reference':'sddm-0.19.0-3.fc33', 'release':'FC33', 'rpm_spec_vers_cmp':TRUE}
];

flag = 0;
foreach package_array ( pkgs ) {
  reference = NULL;
  release = NULL;
  sp = NULL;
  cpu = NULL;
  el_string = NULL;
  rpm_spec_vers_cmp = NULL;
  epoch = NULL;
  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_NOTE,
      extra      : rpm_report_get()
  );
  exit(0);
}
else
{
  tested = pkg_tests_get();
  if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested);
  else audit(AUDIT_PACKAGE_NOT_INSTALLED, 'sddm');
}

CVSS2

3.3

Attack Vector

LOCAL

Attack Complexity

MEDIUM

Authentication

NONE

Confidentiality Impact

PARTIAL

Integrity Impact

PARTIAL

Availability Impact

NONE

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

CVSS3

6.3

Attack Vector

LOCAL

Attack Complexity

HIGH

Privileges Required

LOW

User Interaction

NONE

Scope

UNCHANGED

Confidentiality Impact

HIGH

Integrity Impact

HIGH

Availability Impact

NONE

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

AI Score

6.1

Confidence

High

EPSS

0

Percentile

5.1%