Amazon Linux 2022 : polkit (ALAS2022-2022-220)

#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Amazon Linux 2022 Security Advisory ALAS2022-2022-220.
##

include('compat.inc');

if (description)
{
  script_id(168576);
  script_version("1.4");
  script_set_attribute(attribute:"plugin_modification_date", value:"2023/01/12");

  script_cve_id("CVE-2021-4034", "CVE-2021-4115");
  script_xref(name:"IAVA", value:"2022-A-0055");
  script_xref(name:"CISA-KNOWN-EXPLOITED", value:"2022/07/18");

  script_name(english:"Amazon Linux 2022 : polkit (ALAS2022-2022-220)");

  script_set_attribute(attribute:"synopsis", value:
"The remote Amazon Linux 2022 host is missing a security update.");
  script_set_attribute(attribute:"description", value:
"The version of polkit installed on the remote host is prior to 0.117-10. It is, therefore, affected by multiple
vulnerabilities as referenced in the ALAS2022-2022-220 advisory.

  - A local privilege escalation vulnerability was found on polkit's pkexec utility. The pkexec application is
    a setuid tool designed to allow unprivileged users to run commands as privileged users according
    predefined policies. The current version of pkexec doesn't handle the calling parameters count correctly
    and ends trying to execute environment variables as commands. An attacker can leverage this by crafting
    environment variables in such a way it'll induce pkexec to execute arbitrary code. When successfully
    executed the attack can cause a local privilege escalation given unprivileged users administrative rights
    on the target machine. (CVE-2021-4034)

  - There is a flaw in polkit which can allow an unprivileged user to cause polkit to crash, due to process
    file descriptor exhaustion. The highest threat from this vulnerability is to availability. NOTE: Polkit
    process outage duration is tied to the failing process being reaped and a new one being spawned
    (CVE-2021-4115)

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://alas.aws.amazon.com/AL2022/ALAS-2022-220.html");
  script_set_attribute(attribute:"see_also", value:"https://alas.aws.amazon.com/cve/html/CVE-2021-4034.html");
  script_set_attribute(attribute:"see_also", value:"https://alas.aws.amazon.com/cve/html/CVE-2021-4115.html");
  script_set_attribute(attribute:"solution", value:
"Run 'yum update polkit' to update your system.");
  script_set_cvss_base_vector("CVSS2#AV:L/AC:L/Au:N/C:C/I:C/A:C");
  script_set_cvss_temporal_vector("CVSS2#E:H/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:H/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2021-4034");

  script_set_attribute(attribute:"exploitability_ease", value:"Exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"true");
  script_set_attribute(attribute:"exploit_framework_core", value:"true");
  script_set_attribute(attribute:"exploited_by_malware", value:"true");
  script_set_attribute(attribute:"metasploit_name", value:'Local Privilege Escalation in polkits pkexec');
  script_set_attribute(attribute:"exploit_framework_metasploit", value:"true");
  script_set_attribute(attribute:"exploit_framework_canvas", value:"true");
  script_set_attribute(attribute:"canvas_package", value:"CANVAS");

  script_set_attribute(attribute:"vuln_publication_date", value:"2022/01/25");
  script_set_attribute(attribute:"patch_publication_date", value:"2022/12/06");
  script_set_attribute(attribute:"plugin_publication_date", value:"2022/12/09");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:polkit");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:polkit-debuginfo");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:polkit-debugsource");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:polkit-devel");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:polkit-docs");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:polkit-libs");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:polkit-libs-debuginfo");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:amazon:linux:2022");
  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:"Amazon Linux Local Security Checks");

  script_copyright(english:"This script is Copyright (C) 2022-2023 and is owned by Tenable, Inc. or an Affiliate thereof.");

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

  exit(0);
}

include("rpm.inc");

if (!get_kb_item("Host/local_checks_enabled")) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);

var alas_release = get_kb_item("Host/AmazonLinux/release");
if (isnull(alas_release) || !strlen(alas_release)) audit(AUDIT_OS_NOT, "Amazon Linux");
var os_ver = pregmatch(pattern: "^AL(A|\d+|-\d+)", string:alas_release);
if (isnull(os_ver)) audit(AUDIT_UNKNOWN_APP_VER, "Amazon Linux");
os_ver = os_ver[1];
if (os_ver != "-2022")
{
  if (os_ver == 'A') os_ver = 'AMI';
  audit(AUDIT_OS_NOT, "Amazon Linux 2022", "Amazon Linux " + os_ver);
}

if (!get_kb_item("Host/AmazonLinux/rpm-list")) audit(AUDIT_PACKAGE_LIST_MISSING);

var pkgs = [
    {'reference':'polkit-0.117-10.amzn2022.0.2', 'cpu':'aarch64', 'release':'AL-2022', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'polkit-0.117-10.amzn2022.0.2', 'cpu':'i686', 'release':'AL-2022', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'polkit-0.117-10.amzn2022.0.2', 'cpu':'x86_64', 'release':'AL-2022', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'polkit-debuginfo-0.117-10.amzn2022.0.2', 'cpu':'aarch64', 'release':'AL-2022', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'polkit-debuginfo-0.117-10.amzn2022.0.2', 'cpu':'i686', 'release':'AL-2022', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'polkit-debuginfo-0.117-10.amzn2022.0.2', 'cpu':'x86_64', 'release':'AL-2022', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'polkit-debugsource-0.117-10.amzn2022.0.2', 'cpu':'aarch64', 'release':'AL-2022', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'polkit-debugsource-0.117-10.amzn2022.0.2', 'cpu':'i686', 'release':'AL-2022', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'polkit-debugsource-0.117-10.amzn2022.0.2', 'cpu':'x86_64', 'release':'AL-2022', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'polkit-devel-0.117-10.amzn2022.0.2', 'cpu':'aarch64', 'release':'AL-2022', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'polkit-devel-0.117-10.amzn2022.0.2', 'cpu':'i686', 'release':'AL-2022', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'polkit-devel-0.117-10.amzn2022.0.2', 'cpu':'x86_64', 'release':'AL-2022', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'polkit-docs-0.117-10.amzn2022.0.2', 'release':'AL-2022', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'polkit-libs-0.117-10.amzn2022.0.2', 'cpu':'aarch64', 'release':'AL-2022', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'polkit-libs-0.117-10.amzn2022.0.2', 'cpu':'i686', 'release':'AL-2022', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'polkit-libs-0.117-10.amzn2022.0.2', 'cpu':'x86_64', 'release':'AL-2022', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'polkit-libs-debuginfo-0.117-10.amzn2022.0.2', 'cpu':'aarch64', 'release':'AL-2022', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'polkit-libs-debuginfo-0.117-10.amzn2022.0.2', 'cpu':'i686', 'release':'AL-2022', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'polkit-libs-debuginfo-0.117-10.amzn2022.0.2', 'cpu':'x86_64', 'release':'AL-2022', '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 = 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_HOLE,
      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, "polkit / polkit-debuginfo / polkit-debugsource / etc");
}