Ubuntu 18.04 LTS / 20.04 LTS / 22.04 LTS / 24.04 LTS : CryptX vulnerabilities (USN-8128-1)

#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Ubuntu Security Notice USN-8128-1. The text
# itself is copyright (C) Canonical, Inc. See
# <https://ubuntu.com/security/notices>. Ubuntu(R) is a registered
# trademark of Canonical, Inc.
##

include('compat.inc');

if (description)
{
  script_id(304013);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/03/27");

  script_cve_id("CVE-2018-25099", "CVE-2025-40912", "CVE-2025-40914");
  script_xref(name:"USN", value:"8128-1");

  script_name(english:"Ubuntu 18.04 LTS / 20.04 LTS / 22.04 LTS / 24.04 LTS : CryptX vulnerabilities (USN-8128-1)");

  script_set_attribute(attribute:"synopsis", value:
"The remote Ubuntu host is missing one or more security updates.");
  script_set_attribute(attribute:"description", value:
"The remote Ubuntu 18.04 LTS / 20.04 LTS / 22.04 LTS / 24.04 LTS host has a package installed that is affected by
multiple vulnerabilities as referenced in the USN-8128-1 advisory.

    It was discovered that CryptX did not verify authentication tags while performing GCM and
    ChaCha20-Poly1305 decryption. An attacker could possibly use this issue to cause CryptX to accept modified
    ciphertext, leading to data integrity violations or authentication bypass. This issue only affected Ubuntu
    18.04 LTS. (CVE-2018-25099)

    It was discovered that CryptX included a version of the tomcrypt library that was susceptible to malformed
    unicode handling. An attacker could possibly use this issue to cause unexpected behavior or incorrect
    processing of crafted input. This issue only affected Ubuntu 18.04 LTS. (CVE-2025-40912)

    It was discovered that CryptX included a version of the libtommath library that was susceptible to an
    integer overflow. An attacker could possibly use this issue to cause memory corruption or a denial of
    service. (CVE-2025-40914)

Tenable has extracted the preceding description block directly from the Ubuntu 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://ubuntu.com/security/notices/USN-8128-1");
  script_set_attribute(attribute:"solution", value:
"Update the affected libcryptx-perl package.");
  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:U/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:U/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2025-40914");

  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:"2024/03/18");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/03/26");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/03/27");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:18.04:-:lts");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:20.04:-:lts");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:22.04:-:lts");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:24.04:-:lts");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:libcryptx-perl");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

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

  script_copyright(english:"Ubuntu Security Notice (C) 2026 Canonical, Inc. / NASL script (C) 2026 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("ssh_get_info.nasl", "ubuntu_pro_sub_detect.nasl");
  script_require_keys("Host/cpu", "Host/Ubuntu", "Host/Ubuntu/release", "Host/Debian/dpkg-l");

  exit(0);
}

include('debian_package.inc');

if ( ! get_kb_item('Host/local_checks_enabled') ) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
var os_release = get_kb_item('Host/Ubuntu/release');
if ( isnull(os_release) ) audit(AUDIT_OS_NOT, 'Ubuntu');
os_release = chomp(os_release);
if (! ('18.04' >< os_release || '20.04' >< os_release || '22.04' >< os_release || '24.04' >< os_release)) audit(AUDIT_OS_NOT, 'Ubuntu 18.04 / 20.04 / 22.04 / 24.04', 'Ubuntu ' + os_release);
if ( ! get_kb_item('Host/Debian/dpkg-l') ) audit(AUDIT_PACKAGE_LIST_MISSING);

var cpu = get_kb_item('Host/cpu');
if (isnull(cpu)) audit(AUDIT_UNKNOWN_ARCH);
if ('x86_64' >!< cpu && cpu !~ "^i[3-6]86$" && 's390' >!< cpu && 'aarch64' >!< cpu) audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, 'Ubuntu', cpu);
var ubuntu_pro_detected = get_kb_item('Host/Ubuntu/Pro/Services/esm-apps');
ubuntu_pro_detected = !empty_or_null(ubuntu_pro_detected);

var pro_caveat_needed = FALSE;

var pkgs = [
    {'osver': '18.04', 'pkgname': 'libcryptx-perl', 'pkgver': '0.056-1ubuntu0.1~esm1', 'ubuntu_pro': TRUE, 'cves': ['CVE-2018-25099', 'CVE-2025-40912', 'CVE-2025-40914']},
    {'osver': '20.04', 'pkgname': 'libcryptx-perl', 'pkgver': '0.067-1ubuntu0.1~esm1', 'ubuntu_pro': TRUE, 'cves': ['CVE-2025-40914']},
    {'osver': '22.04', 'pkgname': 'libcryptx-perl', 'pkgver': '0.076-1ubuntu0.1~esm1', 'ubuntu_pro': TRUE, 'cves': ['CVE-2025-40914']},
    {'osver': '24.04', 'pkgname': 'libcryptx-perl', 'pkgver': '0.080-2ubuntu0.1~esm1', 'ubuntu_pro': TRUE, 'cves': ['CVE-2025-40914']}
];

var flag = 0;
foreach var package_array ( pkgs ) {
  var osver = NULL;
  var pkgname = NULL;
  var pkgver = NULL;
  if (!empty_or_null(package_array['osver'])) osver = package_array['osver'];
  if (!empty_or_null(package_array['pkgname'])) pkgname = package_array['pkgname'];
  if (!empty_or_null(package_array['pkgver'])) pkgver = package_array['pkgver'];
  if (!empty_or_null(package_array['cves'])) cves = package_array['cves'];
  var pro_required = NULL;
  if (!empty_or_null(package_array['ubuntu_pro'])) pro_required = package_array['ubuntu_pro'];
  if (osver && pkgname && pkgver) {
    if (deb_check(release:osver, prefix:pkgname, reference:pkgver, cves:cves)) {
        flag++;
        if (!ubuntu_pro_detected && !pro_caveat_needed) pro_caveat_needed = pro_required;
    }
  }
}

if (flag)
{
  var extra = '';
  if (pro_caveat_needed) {
    extra += 'NOTE: This vulnerability check contains fixes that apply to packages only \n';
    extra += 'available in Ubuntu ESM repositories. Access to these package security updates \n';
    extra += 'require an Ubuntu Pro subscription.\n\n';
  }
  extra += ubuntu_report_get();
  security_report_v4(
    port       : 0,
    severity   : SECURITY_HOLE,
    extra      : extra
  );
  exit(0);
}
else
{
  var tested = ubuntu_pkg_tests_get();
  if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested);
  else audit(AUDIT_PACKAGE_NOT_INSTALLED, 'libcryptx-perl');
}