Amazon Linux 2 : clamav1.4, --advisory ALAS2-2026-3820 (ALAS-2026-3820)

#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Amazon Linux 2 Security Advisory ALAS-2026-3820.
##

include('compat.inc');

if (description)
{
  script_id(328849);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/07/21");

  script_cve_id(
    "CVE-2026-20213",
    "CVE-2026-20214",
    "CVE-2026-20215",
    "CVE-2026-20216",
    "CVE-2026-20217",
    "CVE-2026-20243"
  );
  script_xref(name:"IAVA", value:"2026-A-0653");

  script_name(english:"Amazon Linux 2 : clamav1.4, --advisory ALAS2-2026-3820 (ALAS-2026-3820)");

  script_set_attribute(attribute:"synopsis", value:
"The remote Amazon Linux 2 host is missing a security update.");
  script_set_attribute(attribute:"description", value:
"The version of clamav1.4 installed on the remote host is prior to 1.4.5-1. It is, therefore, affected by multiple
vulnerabilities as referenced in the ALAS2-2026-3820 advisory.

    A vulnerability in the PE file format parser of ClamAV could allow an unauthenticated, remote attacker to
    cause a DoS condition, or possibly other expanded impacts, resulting from memory corruption on an affected
    device.This vulnerability is due to improper boundary checks for content in PE files during scanning,
    which may result in an out-of-bounds buffer write. An attacker could exploit this vulnerability by
    submitting a crafted file that contains PE content to be scanned by ClamAV on an affected device. A
    successful exploit could allow the attacker to cause the ClamAV scanning process to terminate, resulting
    in a DoS condition on the affected software. (CVE-2026-20213)

    A vulnerability in the FSG file format parser of ClamAV could allow an unauthenticated, remote attacker to
    cause a DoS condition, or possibly other expanded impacts, resulting from memory corruption on an affected
    device.This vulnerability is due to improper boundary checks for content in FSG files during scanning,
    which may result in an out-of-bounds buffer write. An attacker could exploit this vulnerability by
    submitting a crafted file that contains portable executable content compressed with FSG to be scanned by
    ClamAV on an affected device. A successful exploit could allow the attacker to cause the ClamAV scanning
    process to terminate, resulting in a DoS condition on the affected software. (CVE-2026-20214)

    A vulnerability in the 7z file format parser of ClamAV could allow an unauthenticated, remote attacker to
    cause a DoS condition, or possibly other expanded impacts, resulting from memory corruption on an affected
    device.This vulnerability is due to improper boundary checks for content in 7z files during scanning,
    which may result in an out-of-bounds buffer write. An attacker could exploit this vulnerability by
    submitting a crafted file that contains 7zcontent to be scanned by ClamAV on an affected device. A
    successful exploit could allow the attacker to cause the ClamAV scanning process to terminate, resulting
    in a DoS condition on the affected software. (CVE-2026-20215)

    A vulnerability in the InstallShield file format parser of ClamAV could allow an unauthenticated, remote
    attacker to cause a DoS condition on an affected device.This vulnerability is due to improper handling of
    temporary resources during file scanning. An attacker could exploit this vulnerability by submitting a
    crafted InstallShield file to be scanned by ClamAV on an affected device. A successful exploit could allow
    the attacker to terminate the ClamAV scanning process and temporarily consume available system resources,
    resulting in a DoS condition on the affected software. (CVE-2026-20216)

    A vulnerability in the PESpin file format parser of ClamAV could allow an unauthenticated, remote attacker
    to cause a DoS condition, or possibly other expanded impacts, resulting from memory corruption on an
    affected device.This vulnerability is due to improper boundary checks for content in PESpin files during
    scanning, which may result in an out-of-bounds buffer write. An attacker could exploit this vulnerability
    by submitting a crafted file that contains PESpin content to be scanned by ClamAV on an affected device. A
    successful exploit could allow the attacker to cause the ClamAV scanning process to terminate, resulting
    in a DoS condition on the affected software. (CVE-2026-20217)

    A vulnerability in the ALZ file format parser of ClamAV could allow an unauthenticated, remote attacker to
    cause a DoS condition, or possibly other expanded impacts, resulting from memory corruption on an affected
    device.This vulnerability is due to improper boundary checks for content in ALZ files during scanning,
    which may result in an out-of-bounds buffer write. An attacker could exploit this vulnerability by
    submitting a crafted file that contains ALZ content to be scanned by ClamAV on an affected device. A
    successful exploit could allow the attacker to cause the ClamAV scanning process to terminate, resulting
    in a DoS condition on the affected software. (CVE-2026-20243)

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

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//AL2/ALAS2-2026-3820.html");
  script_set_attribute(attribute:"see_also", value:"https://alas.aws.amazon.com/faqs.html");
  script_set_attribute(attribute:"see_also", value:"https://explore.alas.aws.amazon.com/CVE-2026-20213.html");
  script_set_attribute(attribute:"see_also", value:"https://explore.alas.aws.amazon.com/CVE-2026-20214.html");
  script_set_attribute(attribute:"see_also", value:"https://explore.alas.aws.amazon.com/CVE-2026-20215.html");
  script_set_attribute(attribute:"see_also", value:"https://explore.alas.aws.amazon.com/CVE-2026-20216.html");
  script_set_attribute(attribute:"see_also", value:"https://explore.alas.aws.amazon.com/CVE-2026-20217.html");
  script_set_attribute(attribute:"see_also", value:"https://explore.alas.aws.amazon.com/CVE-2026-20243.html");
  script_set_attribute(attribute:"solution", value:
"Run 'yum update clamav1.4' or
  or 'yum update --advisory ALAS2-2026-3820' to update your system.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:N/I:N/A:C");
  script_set_cvss_temporal_vector("CVSS2#E:U/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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-2026-20243");

  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:"2026/07/01");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/07/20");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/07/21");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:clamav1.4");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:clamav1.4-data");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:clamav1.4-debuginfo");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:clamav1.4-devel");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:clamav1.4-doc");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:clamav1.4-filesystem");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:clamav1.4-freshclam");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:clamav1.4-lib");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:clamav1.4-milter");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:clamd1.4");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:amazon:linux:2");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_set_attribute(attribute:"stig_severity", value:"II");
  script_end_attributes();

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

  script_copyright(english:"This script is Copyright (C) 2026 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("rpm2.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 != "2")
{
  if (os_ver == 'A') os_ver = 'AMI';
  audit(AUDIT_OS_NOT, "Amazon Linux 2", "Amazon Linux " + os_ver);
}

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

var pkgs = [
    {'reference':'clamav1.4-1.4.5-1.amzn2.0.1', 'cpu':'aarch64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'clamav1.4-1.4.5-1.amzn2.0.1', 'cpu':'x86_64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'clamav1.4-data-1.4.5-1.amzn2.0.1', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'clamav1.4-debuginfo-1.4.5-1.amzn2.0.1', 'cpu':'aarch64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'clamav1.4-debuginfo-1.4.5-1.amzn2.0.1', 'cpu':'x86_64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'clamav1.4-devel-1.4.5-1.amzn2.0.1', 'cpu':'aarch64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'clamav1.4-devel-1.4.5-1.amzn2.0.1', 'cpu':'x86_64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'clamav1.4-doc-1.4.5-1.amzn2.0.1', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'clamav1.4-filesystem-1.4.5-1.amzn2.0.1', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'clamav1.4-freshclam-1.4.5-1.amzn2.0.1', 'cpu':'aarch64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'clamav1.4-freshclam-1.4.5-1.amzn2.0.1', 'cpu':'x86_64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'clamav1.4-lib-1.4.5-1.amzn2.0.1', 'cpu':'aarch64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'clamav1.4-lib-1.4.5-1.amzn2.0.1', 'cpu':'x86_64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'clamav1.4-milter-1.4.5-1.amzn2.0.1', 'cpu':'aarch64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'clamav1.4-milter-1.4.5-1.amzn2.0.1', 'cpu':'x86_64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'clamd1.4-1.4.5-1.amzn2.0.1', 'cpu':'aarch64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'clamd1.4-1.4.5-1.amzn2.0.1', 'cpu':'x86_64', 'release':'AL2', '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, "clamav1.4 / clamav1.4-data / clamav1.4-debuginfo / etc");
}