CentOS Linux 7 [TuxCare] Security Update: libgcrypt / libgcrypt-devel Multiple Vulnerabilities (CENTOS7:CLSA-2023:1698945053)

#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
##

include('compat.inc');

if (description)
{
  script_id(362123);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/10/01");

  script_cve_id(
    "CVE-2013-4576",
    "CVE-2014-3591",
    "CVE-2021-33560",
    "CVE-2021-40528"
  );
  script_xref(name:"CLSA", value:"2023:1698945053");

  script_name(english:"CentOS Linux 7 [TuxCare] Security Update: libgcrypt / libgcrypt-devel Multiple Vulnerabilities (CENTOS7:CLSA-2023:1698945053)");

  script_set_attribute(attribute:"synopsis", value:
"The CentOS Linux host is missing one or more security updates.");
  script_set_attribute(attribute:"description", value:
"The CentOS Linux 7 host has packages installed that are affected by multiple vulnerabilities as referenced in the
TuxCare CENTOS7:CLSA-2023:1698945053 advisory.

  - GnuPG 1.x before 1.4.16 generates RSA keys using sequences of introductions with certain patterns that
    introduce a side channel, which allows physically proximate attackers to extract RSA keys via a chosen-
    ciphertext attack and acoustic cryptanalysis during decryption. NOTE: applications are not typically
    expected to protect themselves from acoustic side-channel attacks, since this is arguably the
    responsibility of the physical device. Accordingly, issues of this type would not normally receive a CVE
    identifier. However, for this issue, the developer has specified a security policy in which GnuPG should
    offer side-channel resistance, and developer-specified security-policy violations are within the scope of
    CVE. (CVE-2013-4576)

  - Libgcrypt before 1.6.3 and GnuPG before 1.4.19 does not implement ciphertext blinding for Elgamal
    decryption, which allows physically proximate attackers to obtain the server's private key by determining
    factors using crafted ciphertext and the fluctuations in the electromagnetic field during multiplication.
    (CVE-2014-3591)

  - Libgcrypt before 1.8.8 and 1.9.x before 1.9.3 mishandles ElGamal encryption because it lacks exponent
    blinding to address a side-channel attack against mpi_powm, and the window size is not chosen
    appropriately. This, for example, affects use of ElGamal in OpenPGP. (CVE-2021-33560)

  - The ElGamal implementation in Libgcrypt before 1.9.4 allows plaintext recovery because, during interaction
    between two cryptographic libraries, a certain dangerous combination of the prime defined by the
    receiver's public key, the generator defined by the receiver's public key, and the sender's ephemeral
    exponents can lead to a cross-configuration attack against OpenPGP. (CVE-2021-40528)

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version
number.");
  # https://security.tuxcare.com/csaf/v2/els_os/centos7els/advisories/2023/clsa-2023_1698945053.json
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?93341f06");
  script_set_attribute(attribute:"see_also", value:"https://cve.tuxcare.com/els/releases/CLSA-2023:1698945053");
  script_set_attribute(attribute:"solution", value:
"Update the affected packages based on the guidance in TuxCare advisory CENTOS7:CLSA-2023:1698945053.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:P/I:N/A:N");
  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:N/A:N");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:P/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2021-33560");

  script_set_attribute(attribute:"exploitability_ease", value:"Exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"true");
  script_set_attribute(attribute:"vendor_severity", value:"Important");

  script_set_attribute(attribute:"vuln_publication_date", value:"2013/12/18");
  script_set_attribute(attribute:"patch_publication_date", value:"2023/11/02");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/10/01");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"CentOS 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/OS/extended-third-party", "Host/local_checks_enabled", "Host/CentOS/release", "Host/CentOS/rpm-list");

  exit(0);
}
include('rpm2.inc');

var third_party_support = get_kb_item('Host/OS/extended-third-party');
if (empty_or_null(third_party_support) || third_party_support != 'TuxCare') exit(0, 'TuxCare support not enabled.');

if (!get_kb_item('Host/local_checks_enabled')) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
var os_product = get_kb_item('installed_os/local/SSH/0/product');
if (isnull(os_product) || 'CentOS Linux' >!< os_product) audit(AUDIT_OS_NOT, 'CentOS Linux');
var os_version = get_kb_item('installed_os/local/SSH/0/version');
if (isnull(os_version)) audit(AUDIT_UNKNOWN_APP_VER, 'CentOS Linux');
if (! preg(pattern:"^7([^0-9]|$)", string:os_version)) audit(AUDIT_OS_NOT, 'CentOS Linux 7', 'CentOS Linux ' + os_version);

if (!get_kb_item('Host/CentOS/rpm-list')) audit(AUDIT_PACKAGE_LIST_MISSING);

var cpu = get_kb_item('Host/cpu');
if (isnull(cpu)) audit(AUDIT_UNKNOWN_ARCH);
if (cpu !~ "^i[3-6]86$" && 'x86_64' >!< cpu) audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, 'CentOS Linux', cpu);


var constraints = [
  {
    'release': '7',
    'pkgs': [
      {'reference':'libgcrypt-1.5.3-14.el7.tuxcare.els1', 'cpu':'i686', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'libgcrypt-1.5.3-14.el7.tuxcare.els1', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'libgcrypt-devel-1.5.3-14.el7.tuxcare.els1', 'cpu':'i686', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'libgcrypt-devel-1.5.3-14.el7.tuxcare.els1', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE}
    ]
  }
];

var os_release = get_one_kb_item('installed_os/local/SSH/0/release');
var os_sp = get_one_kb_item('Host/*/minor_release');

var flag = 0;
var reference;
var sp;
var _cpu;
var el_string;
var rpm_spec_vers_cmp;
var epoch;
var allowmaj;
var exists_check;
var cves;
foreach var constraint ( constraints ) {
  # Check that the target release is equal to the affected release
  if (!empty_or_null(constraint['release'])){
    if (constraint['release'] != os_release) continue;
  }
  if (!empty_or_null(constraint['sp'])){
    if (constraint['sp'] != os_sp) continue;
  }
  foreach var pkg ( constraint['pkgs'] ) {
    reference = NULL;
    sp = NULL;
    _cpu = NULL;
    el_string = NULL;
    rpm_spec_vers_cmp = NULL;
    epoch = NULL;
    allowmaj = NULL;
    exists_check = NULL;
    cves = NULL;
    if (!empty_or_null(pkg['reference'])) reference = pkg['reference'];
    if (!empty_or_null(pkg['sp'])) sp = pkg['sp'];
    if (!empty_or_null(pkg['cpu'])) _cpu = pkg['cpu'];
    if (!empty_or_null(pkg['el_string'])) el_string = pkg['el_string'];
    if (!empty_or_null(pkg['rpm_spec_vers_cmp'])) rpm_spec_vers_cmp = pkg['rpm_spec_vers_cmp'];
    if (!empty_or_null(pkg['epoch'])) epoch = pkg['epoch'];
    if (!empty_or_null(pkg['allowmaj'])) allowmaj = pkg['allowmaj'];
    if (!empty_or_null(pkg['exists_check'])) exists_check = pkg['exists_check'];
    if (!empty_or_null(pkg['cves'])) cves = pkg['cves'];
    if (reference &&
        ## (no known rpm to check OR known rpm_exists)
        (!exists_check || rpm_exists(rpm:exists_check)) &&
        rpm_check(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_WARNING,
      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, 'libgcrypt / libgcrypt-devel');
}