Amazon Linux 2023 : openssh, openssh-clients, openssh-keycat (ALAS2023-2023-273)

#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Amazon Linux 2023 Security Advisory ALAS2023-2023-273.
##

include('compat.inc');

if (description)
{
  script_id(179760);
  script_version("1.3");
  script_set_attribute(attribute:"plugin_modification_date", value:"2024/12/11");

  script_cve_id("CVE-2023-38408");
  script_xref(name:"IAVA", value:"2023-A-0377-S");

  script_name(english:"Amazon Linux 2023 : openssh, openssh-clients, openssh-keycat (ALAS2023-2023-273)");

  script_set_attribute(attribute:"synopsis", value:
"The remote Amazon Linux 2023 host is missing a security update.");
  script_set_attribute(attribute:"description", value:
"It is, therefore, affected by a vulnerability as referenced in the ALAS2023-2023-273 advisory.

    The PKCS#11 feature in ssh-agent in OpenSSH before 9.3p2 has an insufficiently trustworthy search path,
    leading to remote code execution if the target user's ssh-agent is forwarded to an attacker-controlled
    system (the code in /usr/lib is not necessarily safe for loading into ssh-agent). Exploitation can also be
    prevented by starting ssh-agent with an empty PKCS#11/FIDO allowlist (ssh-agent -P '') or by configuring
    an allowlist that contains only specific provider libraries. NOTE: this issue exists because of an
    incomplete fix for CVE-2016-10009. (CVE-2023-38408)

Tenable has extracted the preceding description block directly from the tested product security advisory.

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/AL2023/ALAS-2023-273.html");
  script_set_attribute(attribute:"see_also", value:"https://alas.aws.amazon.com/cve/html/CVE-2023-38408.html");
  script_set_attribute(attribute:"see_also", value:"https://alas.aws.amazon.com/faqs.html");
  script_set_attribute(attribute:"solution", value:
"Run 'dnf update openssh --releasever 2023.1.20230809' to update your system.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:C/I:C/A:C");
  script_set_cvss_temporal_vector("CVSS2#E:POC/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:P/RL:O/RC:C");
  script_set_attribute(attribute:"cvss4_vector", value:"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N");
  script_set_attribute(attribute:"cvss4_threat_vector", value:"CVSS:4.0/E:P");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2023-38408");

  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:"2023/07/20");
  script_set_attribute(attribute:"patch_publication_date", value:"2023/08/03");
  script_set_attribute(attribute:"plugin_publication_date", value:"2023/08/14");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:openssh");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:openssh-clients");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:openssh-clients-debuginfo");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:openssh-debuginfo");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:openssh-debugsource");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:openssh-keycat");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:openssh-keycat-debuginfo");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:openssh-server");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:openssh-server-debuginfo");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:pam_ssh_agent_auth");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:pam_ssh_agent_auth-debuginfo");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:amazon:linux:2023");
  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) 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/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 != "-2023")
{
  if (os_ver == 'A') os_ver = 'AMI';
  audit(AUDIT_OS_NOT, "Amazon Linux 2023", "Amazon Linux " + os_ver);
}

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

var pkgs = [
    {'reference':'openssh-8.7p1-8.amzn2023.0.7', 'cpu':'aarch64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE, 'allowmaj':TRUE},
    {'reference':'openssh-8.7p1-8.amzn2023.0.7', 'cpu':'x86_64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE, 'allowmaj':TRUE},
    {'reference':'openssh-clients-8.7p1-8.amzn2023.0.7', 'cpu':'aarch64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE, 'allowmaj':TRUE},
    {'reference':'openssh-clients-8.7p1-8.amzn2023.0.7', 'cpu':'x86_64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE, 'allowmaj':TRUE},
    {'reference':'openssh-clients-debuginfo-8.7p1-8.amzn2023.0.7', 'cpu':'aarch64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE, 'allowmaj':TRUE},
    {'reference':'openssh-clients-debuginfo-8.7p1-8.amzn2023.0.7', 'cpu':'x86_64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE, 'allowmaj':TRUE},
    {'reference':'openssh-debuginfo-8.7p1-8.amzn2023.0.7', 'cpu':'aarch64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE, 'allowmaj':TRUE},
    {'reference':'openssh-debuginfo-8.7p1-8.amzn2023.0.7', 'cpu':'x86_64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE, 'allowmaj':TRUE},
    {'reference':'openssh-debugsource-8.7p1-8.amzn2023.0.7', 'cpu':'aarch64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE, 'allowmaj':TRUE},
    {'reference':'openssh-debugsource-8.7p1-8.amzn2023.0.7', 'cpu':'x86_64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE, 'allowmaj':TRUE},
    {'reference':'openssh-keycat-8.7p1-8.amzn2023.0.7', 'cpu':'aarch64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE, 'allowmaj':TRUE},
    {'reference':'openssh-keycat-8.7p1-8.amzn2023.0.7', 'cpu':'x86_64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE, 'allowmaj':TRUE},
    {'reference':'openssh-keycat-debuginfo-8.7p1-8.amzn2023.0.7', 'cpu':'aarch64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE, 'allowmaj':TRUE},
    {'reference':'openssh-keycat-debuginfo-8.7p1-8.amzn2023.0.7', 'cpu':'x86_64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE, 'allowmaj':TRUE},
    {'reference':'openssh-server-8.7p1-8.amzn2023.0.7', 'cpu':'aarch64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE, 'allowmaj':TRUE},
    {'reference':'openssh-server-8.7p1-8.amzn2023.0.7', 'cpu':'x86_64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE, 'allowmaj':TRUE},
    {'reference':'openssh-server-debuginfo-8.7p1-8.amzn2023.0.7', 'cpu':'aarch64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE, 'allowmaj':TRUE},
    {'reference':'openssh-server-debuginfo-8.7p1-8.amzn2023.0.7', 'cpu':'x86_64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE, 'allowmaj':TRUE},
    {'reference':'pam_ssh_agent_auth-0.10.4-4.8.amzn2023.0.7', 'cpu':'aarch64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'pam_ssh_agent_auth-0.10.4-4.8.amzn2023.0.7', 'cpu':'x86_64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'pam_ssh_agent_auth-debuginfo-0.10.4-4.8.amzn2023.0.7', 'cpu':'aarch64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'pam_ssh_agent_auth-debuginfo-0.10.4-4.8.amzn2023.0.7', 'cpu':'x86_64', 'release':'AL-2023', '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;
  var cves = 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 (!empty_or_null(package_array['cves'])) cves = package_array['cves'];
  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, cves:cves)) 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, "openssh / openssh-clients / openssh-clients-debuginfo / etc");
}