Amazon Linux 2023 : libssh, libssh-config, libssh-devel (ALAS2023-2025-1264)

#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Amazon Linux 2023 Security Advisory ALAS2023-2025-1264.
##

include('compat.inc');

if (description)
{
  script_id(274674);
  script_version("1.2");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/02/24");

  script_cve_id("CVE-2025-8114", "CVE-2025-8277");
  script_xref(name:"IAVA", value:"2025-A-0692-S");

  script_name(english:"Amazon Linux 2023 : libssh, libssh-config, libssh-devel (ALAS2023-2025-1264)");

  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 multiple vulnerabilities as referenced in the ALAS2023-2025-1264 advisory.

    NULL Pointer Dereference vulnerability in the session ID calculation logic of the libssh library. The flaw
    arises from improper handling of allocation errors during cryptographic operations in the key exchange
    (KEX) phase. If a memory allocation fails, the resulting NULL pointer may be dereferenced, leading to a
    crash in both SSH clients and servers. This vulnerability can be exploited by a local attacker with
    limited privileges and no user interaction, potentially disrupting services that rely on libssh for secure
    communication.The issue affects libssh versions up to and including 0.11.2. (CVE-2025-8114)

    A flaw was found in libssh's handling of key exchange (KEX) processes when a client repeatedly sends
    incorrect KEX guesses. The library fails to free memory during these rekey operations, which can gradually
    exhaust system memory. This issue can lead to crashes on the client side, particularly when using
    libgcrypt, which impacts application stability and availability. (CVE-2025-8277)

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//AL2023/ALAS2023-2025-1264.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-2025-8114.html");
  script_set_attribute(attribute:"see_also", value:"https://explore.alas.aws.amazon.com/CVE-2025-8277.html");
  script_set_attribute(attribute:"solution", value:
"Run 'dnf update libssh --releasever 2023.9.20251110' or
  or 'dnf update --advisory ALAS2023-2025-1264 --releasever 2023.9.20251110' to update your system.");
  script_set_cvss_base_vector("CVSS2#AV:L/AC:H/Au:S/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:L/AC:H/PR:L/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-2025-8114");

  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:"2025/07/24");
  script_set_attribute(attribute:"patch_publication_date", value:"2025/11/10");
  script_set_attribute(attribute:"plugin_publication_date", value:"2025/11/11");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:libssh");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:libssh-config");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:libssh-debuginfo");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:libssh-debugsource");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:libssh-devel");
  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:"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) 2025-2026 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("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':'libssh-0.10.6-1.amzn2023.0.3', 'cpu':'aarch64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'libssh-0.10.6-1.amzn2023.0.3', 'cpu':'x86_64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'libssh-config-0.10.6-1.amzn2023.0.3', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'libssh-debuginfo-0.10.6-1.amzn2023.0.3', 'cpu':'aarch64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'libssh-debuginfo-0.10.6-1.amzn2023.0.3', 'cpu':'x86_64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'libssh-debugsource-0.10.6-1.amzn2023.0.3', 'cpu':'aarch64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'libssh-debugsource-0.10.6-1.amzn2023.0.3', 'cpu':'x86_64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'libssh-devel-0.10.6-1.amzn2023.0.3', 'cpu':'aarch64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'libssh-devel-0.10.6-1.amzn2023.0.3', '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_NOTE,
      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, "libssh / libssh-config / libssh-debuginfo / etc");
}