Amazon Linux 2 : openssl (ALAS-2026-3992)

#%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-2026-3992.
##

include('compat.inc');

if (description)
{
  script_id(365222);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/10/12");

  script_cve_id("CVE-2026-35189", "CVE-2026-54872", "CVE-2026-84782");
  script_xref(name:"IAVA", value:"2026-A-1072");

  script_name(english:"Amazon Linux 2 : openssl (ALAS-2026-3992)");

  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 openssl installed on the remote host is prior to 1.0.2k-24. It is, therefore, affected by multiple
vulnerabilities as referenced in the ALAS2-2026-3992 advisory.

    Issue summary: A certificate with many nameRelativeToCRLIssuer CRLdistribution points causes
    disproportionate heap growth when OpenSSL cachesX.509 extensions.

    Impact summary: Receiving a crafted certificate from a malicious peer can leadto significant memory
    pressure and possible Denial of Service in clients orin servers that solicit client certificates.

    CWE: CWE-770: Allocation of Resources Without Limits or Throttling

    Description: A certificate or a set of certificates that fits under the limit forsize of certificates
    accepted from the peer (~100 KiB) can result in allocationof several hundred MiB of resident memory on the
    receiving sideduring a normal TLS handshake.  This may be enough to crash the client orserver, if multiple
    concurrent connections lead to similarly large memoryallocations.

    The fix postpones processing of the CRL distribution points extensions incertificates to the time when the
    processed value is required for CRL processing.This avoids keeping large memory allocations for a long
    time when suchcertificates are received.

    FIPS impact: noThe affected code is outside the FIPS module boundary. (CVE-2026-35189)

    Issue summary: The generic elliptic-curve scalar multiplication used forECDSA and SM2 signature operations
    with curves that do not have a dedicatedimplementation leaks information about the secret nonce through
    timing.

    Impact summary: An attacker able to measure signing times may learninformation about the per-signature
    secret nonce, which over many signaturescan, via a lattice / Hidden Number Problem attack, lead to
    recovery of theprivate key.

    CWE: CWE-208: Observable Timing Discrepancy

    Description: The generic elliptic-curve scalar multiplication used forcurves that do not have a dedicated
    constant-time implementation pads thesecret scalar with non-constant-time BIGNUM operations, so the time
    takendepends on the value of the secret scalar derived from the ECDSA and SM2 nonce.

    The leak is very small; observing it requires a large number ofmeasurements. The effect is largest for
    curves whose group order lieson a machine-word boundary, such as brainpoolP384r1.

    Applications using ECDSA signing over the Brainpool and other generic primecurves, and SM2 signing on
    platforms that use the generic implementation,are vulnerable to this issue.

    The NIST curves P-256, P-384 and P-521 use dedicated constant-timeimplementations and are not affected.

    FIPS Impact: noThe FIPS modules are not affected: the approved NIST curves used in the FIPSprovider have
    dedicated constant-time implementations and do not use theaffected code path. (CVE-2026-54872)

    A flaw was found in OpenSSL. The Datagram Transport Layer Security (DTLS) retransmission mechanism fails
    to properly handle handshake message writes that are suspended before completion. A remote attacker could
    exploit this vulnerability during handshake message retransmission, causing OpenSSL to read past the
    message buffer or overwrite internal state required to resume writing. This issue can result in
    information disclosure through out-of-bounds memory reads or cause a Denial of Service (DoS) by crashing
    the process. (CVE-2026-84782)

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/ALAS2-2026-3992.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-2026-35189.html");
  script_set_attribute(attribute:"see_also", value:"https://explore.alas.aws.amazon.com/CVE-2026-54872.html");
  script_set_attribute(attribute:"see_also", value:"https://explore.alas.aws.amazon.com/CVE-2026-84782.html");
  script_set_attribute(attribute:"solution", value:
"Run 'yum update openssl' or
  or 'yum update --advisory ALAS2-2026-3992' to update your system.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:P/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:L/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-2026-84782");

  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:"2026/09/29");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/10/12");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/10/12");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:openssl");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:openssl-debuginfo");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:openssl-devel");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:openssl-libs");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:openssl-perl");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:openssl-static");
  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:"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) 2026 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("ssh_get_info2.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':'openssl-1.0.2k-24.amzn2.0.23', 'cpu':'aarch64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'openssl-1.0.2k-24.amzn2.0.23', 'cpu':'i686', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'openssl-1.0.2k-24.amzn2.0.23', 'cpu':'x86_64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'openssl-debuginfo-1.0.2k-24.amzn2.0.23', 'cpu':'aarch64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'openssl-debuginfo-1.0.2k-24.amzn2.0.23', 'cpu':'i686', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'openssl-debuginfo-1.0.2k-24.amzn2.0.23', 'cpu':'x86_64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'openssl-devel-1.0.2k-24.amzn2.0.23', 'cpu':'aarch64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'openssl-devel-1.0.2k-24.amzn2.0.23', 'cpu':'i686', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'openssl-devel-1.0.2k-24.amzn2.0.23', 'cpu':'x86_64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'openssl-libs-1.0.2k-24.amzn2.0.23', 'cpu':'aarch64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'openssl-libs-1.0.2k-24.amzn2.0.23', 'cpu':'i686', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'openssl-libs-1.0.2k-24.amzn2.0.23', 'cpu':'x86_64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'openssl-perl-1.0.2k-24.amzn2.0.23', 'cpu':'aarch64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'openssl-perl-1.0.2k-24.amzn2.0.23', 'cpu':'i686', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'openssl-perl-1.0.2k-24.amzn2.0.23', 'cpu':'x86_64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'openssl-static-1.0.2k-24.amzn2.0.23', 'cpu':'aarch64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'openssl-static-1.0.2k-24.amzn2.0.23', 'cpu':'i686', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'openssl-static-1.0.2k-24.amzn2.0.23', '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, "openssl / openssl-debuginfo / openssl-devel / etc");
}