Linux Distros Unpatched Vulnerability : CVE-2023-1998

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

include('compat.inc');

if (description)
{
  script_id(246599);
  script_version("1.11");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/05/21");

  script_cve_id("CVE-2023-1998");

  script_name(english:"Linux Distros Unpatched Vulnerability : CVE-2023-1998");

  script_set_attribute(attribute:"synopsis", value:
"The Linux/Unix host has one or more packages installed with a vulnerability that the vendor indicates will not be
patched.");
  script_set_attribute(attribute:"description", value:
"The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied
patch available.

  - The Linux kernel allows userspace processes to enable mitigations by calling prctl with
    PR_SET_SPECULATION_CTRL which disables the speculation feature as well as by using seccomp. We had noticed
    that on VMs of at least one major cloud provider, the kernel still left the victim process exposed to
    attacks in some cases even after enabling the spectre-BTI mitigation with prctl. The same behavior can be
    observed on a bare-metal machine when forcing the mitigation to IBRS on boot command line. This happened
    because when plain IBRS was enabled (not enhanced IBRS), the kernel had some logic that determined that
    STIBP was not needed. The IBRS bit implicitly protects against cross-thread branch target injection.
    However, with legacy IBRS, the IBRS bit was cleared on returning to userspace, due to performance reasons,
    which disabled the implicit STIBP and left userspace threads vulnerable to cross-thread branch target
    injection against which STIBP protects. (CVE-2023-1998)

Note that Nessus relies on the presence of the package as reported by the vendor.");
  script_set_attribute(attribute:"see_also", value:"https://ubuntu.com/security/CVE-2023-1998");
  script_set_attribute(attribute:"solution", value:
"There is no known solution at this time.");
  script_set_attribute(attribute:"agent", value:"unix");
  script_set_cvss_base_vector("CVSS2#AV:L/AC:M/Au:N/C:P/I:N/A:N");
  script_set_cvss_temporal_vector("CVSS2#E:POC/RL:U/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:N/A:N");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:P/RL:U/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2023-1998");

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

  script_set_attribute(attribute:"vuln_publication_date", value:"2021/07/21");
  script_set_attribute(attribute:"plugin_publication_date", value:"2025/08/09");

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  script_dependencies("ssh_get_info2.nasl", "set_linux_os_id.nasl");
  script_require_keys("Host/cpu", "Host/local_checks_enabled", "global_settings/vendor_unpatched", "Host/OS/identifier");
  script_require_ports("Host/OS/Ubuntu Linux-16.04", "Host/OS/Ubuntu Linux-18.04", "Host/OS/Ubuntu Linux-20.04", "Host/OS/Ubuntu Linux-22.04", "Host/OS/Ubuntu Linux-24.04");

  exit(0);
}

if (!get_kb_item("global_settings/vendor_unpatched")) exit(0, "Unpatched Vulnerabilities Detection not active.");
if (!get_kb_item("Host/local_checks_enabled")) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
if (empty_or_null(get_one_kb_item("Host/Debian/dpkg-l"))) audit(AUDIT_PACKAGE_LIST_MISSING);

include('linux_unpatched.inc');

var distro_constraints_array = {
  "Ubuntu Linux-16.04": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "16.04",
        "pkgs": [
          {"reference": "linux-hwe-edge"}
        ]
      }
    ]
  },
  "Ubuntu Linux-18.04": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "18.04",
        "pkgs": [
          {"reference": "linux-aws-5.0"},
          {"reference": "linux-aws-5.3"},
          {"reference": "linux-azure-5.3"},
          {"reference": "linux-azure-cloud-tools-4.15.0"},
          {"reference": "linux-azure-edge"},
          {"reference": "linux-azure-headers-4.15.0"},
          {"reference": "linux-azure-tools-4.15.0"},
          {"reference": "linux-cloud-tools-4.15.0"},
          {"reference": "linux-gcp-5.3"},
          {"reference": "linux-gcp-headers-4.15.0"},
          {"reference": "linux-gcp-tools-4.15.0"},
          {"reference": "linux-gke-4.15"},
          {"reference": "linux-gke-5.4"},
          {"reference": "linux-gkeop-5.4"},
          {"reference": "linux-headers-4.15.0"},
          {"reference": "linux-hwe"},
          {"reference": "linux-image-4.15.0"},
          {"reference": "linux-image-unsigned-4.15.0"},
          {"reference": "linux-modules-4.15.0"},
          {"reference": "linux-modules-extra-4.15.0"},
          {"reference": "linux-oem-headers-4.15.0"},
          {"reference": "linux-oem-tools-4.15.0"},
          {"reference": "linux-oracle-5.0"},
          {"reference": "linux-oracle-5.3"},
          {"reference": "linux-tools-4.15.0"},
          {"reference": "linux-udebs-azure"},
          {"reference": "linux-udebs-oem"}
        ]
      }
    ]
  },
  "Ubuntu Linux-20.04": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "20.04",
        "pkgs": [
          {"reference": "linux-aws-5.11"},
          {"reference": "linux-aws-5.13"},
          {"reference": "linux-aws-5.8"},
          {"reference": "linux-azure-5.11"},
          {"reference": "linux-azure-5.13"},
          {"reference": "linux-azure-5.8"},
          {"reference": "linux-azure-fde"},
          {"reference": "linux-buildinfo-5.4.0"},
          {"reference": "linux-buildinfo-5.6.0"},
          {"reference": "linux-cloud-tools-5.4.0"},
          {"reference": "linux-cloud-tools-5.6.0"},
          {"reference": "linux-gcp-5.11"},
          {"reference": "linux-gcp-5.13"},
          {"reference": "linux-gcp-5.8"},
          {"reference": "linux-headers-5.4.0"},
          {"reference": "linux-headers-5.6.0"},
          {"reference": "linux-hwe-5.11"},
          {"reference": "linux-hwe-5.13"},
          {"reference": "linux-hwe-5.8"},
          {"reference": "linux-image-5.4.0"},
          {"reference": "linux-image-unsigned-5.6.0"},
          {"reference": "linux-intel-5.13"},
          {"reference": "linux-libc-dev"},
          {"reference": "linux-modules-5.4.0"},
          {"reference": "linux-modules-5.6.0"},
          {"reference": "linux-modules-extra-5.4.0"},
          {"reference": "linux-modules-extra-5.6.0"},
          {"reference": "linux-oem-5.10"},
          {"reference": "linux-oem-5.13"},
          {"reference": "linux-oem-5.6-headers-5.6.0"},
          {"reference": "linux-oem-5.6-tools-5.6.0"},
          {"reference": "linux-oem-5.6-tools-common"},
          {"reference": "linux-oem-5.6-tools-host"},
          {"reference": "linux-oracle-5.11"},
          {"reference": "linux-oracle-5.13"},
          {"reference": "linux-oracle-5.8"},
          {"reference": "linux-raspi2"},
          {"reference": "linux-riscv-5.11"},
          {"reference": "linux-riscv-5.8"},
          {"reference": "linux-riscv-headers-5.4.0"},
          {"reference": "linux-riscv-tools-5.4.0"},
          {"reference": "linux-tools-5.4.0"},
          {"reference": "linux-tools-5.6.0"},
          {"reference": "linux-udebs-generic"},
          {"reference": "linux-udebs-oem"}
        ]
      }
    ]
  },
  "Ubuntu Linux-22.04": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "22.04",
        "pkgs": [
          {"reference": "linux-azure-5.19"},
          {"reference": "linux-azure-fde-5.19"},
          {"reference": "linux-buildinfo-5.15.0"},
          {"reference": "linux-cloud-tools-5.15.0"},
          {"reference": "linux-headers-5.15.0"},
          {"reference": "linux-image-5.15.0"},
          {"reference": "linux-lowlatency-hwe-5.19"},
          {"reference": "linux-modules-5.15.0"},
          {"reference": "linux-modules-extra-5.15.0"},
          {"reference": "linux-oem-6.0"},
          {"reference": "linux-realtime"},
          {"reference": "linux-riscv-headers-5.15.0"},
          {"reference": "linux-riscv-tools-5.15.0"},
          {"reference": "linux-tools-5.15.0"}
        ]
      }
    ]
  },
  "Ubuntu Linux-24.04": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "24.04",
        "pkgs": [
          {"reference": "linux-raspi-realtime"}
        ]
      }
    ]
  }
};

var distro_constraints_values = linux_unpatched::get_distro_constraints(distro_constraints_arr:distro_constraints_array);
if (empty_or_null(distro_constraints_values)) audit(AUDIT_HOST_NOT, 'affected');
var report = linux_unpatched::check_unpatched_constraints(distro_constraints_values:distro_constraints_values);

if (!empty_or_null(report))
{
  security_report_v4(
      port       : 0,
      severity   : SECURITY_NOTE,
      extra      : report
  );
  exit(0);
}
else
{
  audit(AUDIT_HOST_NOT, 'affected');
}