Amazon Linux AMI : sudo (ALAS-2021-1478)

#%NASL_MIN_LEVEL 70300
##
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Amazon Linux AMI Security Advisory ALAS-2021-1478.
##

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

if (description)
{
  script_id(145451);
  script_version("1.10");
  script_set_attribute(attribute:"plugin_modification_date", value:"2023/01/18");

  script_cve_id("CVE-2021-3156");
  script_xref(name:"ALAS", value:"2021-1478");
  script_xref(name:"IAVA", value:"2021-A-0053");
  script_xref(name:"CISA-KNOWN-EXPLOITED", value:"2022/04/27");

  script_name(english:"Amazon Linux AMI : sudo (ALAS-2021-1478)");

  script_set_attribute(attribute:"synopsis", value:
"The remote Amazon Linux AMI host is missing a security update.");
  script_set_attribute(attribute:"description", value:
"The version of sudo installed on the remote host is prior to 1.8.23-9.56. It is, therefore, affected by a vulnerability
as referenced in the ALAS-2021-1478 advisory.

  - When sudo runs a command in shell mode, either via the -s or -i command line option, it escapes special
    characters in the command's arguments with a backslash. The sudoers policy plugin will then remove the
    escape characters from the arguments before evaluating the sudoers policy (which doesn't expect the escape
    characters) if the command is being run in shell mode. (CVE-2021-3156)

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://alas.aws.amazon.com/ALAS-2021-1478.html");
  script_set_attribute(attribute:"see_also", value:"https://access.redhat.com/security/cve/CVE-2021-3156");
  script_set_attribute(attribute:"solution", value:
"Run 'yum update sudo' 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-2021-3156");

  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:'Sudo Heap-Based Buffer Overflow');
  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:"2021/01/26");
  script_set_attribute(attribute:"patch_publication_date", value:"2021/01/26");
  script_set_attribute(attribute:"plugin_publication_date", value:"2021/01/26");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:sudo");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:sudo-debuginfo");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:sudo-devel");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:amazon:linux");
  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) 2021-2023 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("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/AmazonLinux/release");
if (isnull(release) || !strlen(release)) audit(AUDIT_OS_NOT, "Amazon Linux");
os_ver = pregmatch(pattern: "^AL(A|\d)", string:release);
if (isnull(os_ver)) audit(AUDIT_UNKNOWN_APP_VER, "Amazon Linux");
os_ver = os_ver[1];
if (os_ver != "A")
{
  if (os_ver == 'A') os_ver = 'AMI';
  audit(AUDIT_OS_NOT, "Amazon Linux AMI", "Amazon Linux " + os_ver);
}

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

pkgs = [
    {'reference':'sudo-1.8.23-9.56.amzn1', 'cpu':'i686', 'release':'ALA'},
    {'reference':'sudo-1.8.23-9.56.amzn1', 'cpu':'x86_64', 'release':'ALA'},
    {'reference':'sudo-debuginfo-1.8.23-9.56.amzn1', 'cpu':'i686', 'release':'ALA'},
    {'reference':'sudo-debuginfo-1.8.23-9.56.amzn1', 'cpu':'x86_64', 'release':'ALA'},
    {'reference':'sudo-devel-1.8.23-9.56.amzn1', 'cpu':'i686', 'release':'ALA'},
    {'reference':'sudo-devel-1.8.23-9.56.amzn1', 'cpu':'x86_64', 'release':'ALA'}
];

flag = 0;
foreach package_array ( pkgs ) {
  reference = NULL;
  release = NULL;
  cpu = NULL;
  el_string = NULL;
  rpm_spec_vers_cmp = 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['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['allowmaj'])) allowmaj = package_array['allowmaj'];
  if (reference && release) {
    if (rpm_check(release:release, cpu:cpu, reference:reference, 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
{
  tested = pkg_tests_get();
  if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested);
  else audit(AUDIT_PACKAGE_NOT_INSTALLED, "sudo / sudo-debuginfo / sudo-devel");
}