Linux Distros Unpatched Vulnerability : CVE-2020-29480

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

include('compat.inc');

if (description)
{
  script_id(259117);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2025/08/30");

  script_cve_id("CVE-2020-29480");

  script_name(english:"Linux Distros Unpatched Vulnerability : CVE-2020-29480");

  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.

  - An issue was discovered in Xen through 4.14.x. Neither xenstore implementation does any permission checks
    when reporting a xenstore watch event. A guest administrator can watch the root xenstored node, which will
    cause notifications for every created, modified, and deleted key. A guest administrator can also use the
    special watches, which will cause a notification every time a domain is created and destroyed. Data may
    include: number, type, and domids of other VMs; existence and domids of driver domains; numbers of virtual
    interfaces, block devices, vcpus; existence of virtual framebuffers and their backend style (e.g.,
    existence of VNC service); Xen VM UUIDs for other domains; timing information about domain creation and
    device setup; and some hints at the backend provisioning of VMs and their devices. The watch events do not
    contain values stored in xenstore, only key names. A guest administrator can observe non-sensitive domain
    and device lifecycle events relating to other guests. This information allows some insight into overall
    system configuration (including the number and general nature of other guests), and configuration of other
    guests (including the number and general nature of other guests' devices). This information might be
    commercially interesting or might make other attacks easier. There is not believed to be exposure of
    sensitive data. Specifically, there is no exposure of VNC passwords, port numbers, pathnames in host and
    guest filesystems, cryptographic keys, or within-guest data. (CVE-2020-29480)

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-2020-29480");
  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:L/Au:N/C:P/I:N/A:N");
  script_set_cvss_temporal_vector("CVSS2#E:U/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:L/AC:L/PR:H/UI:N/S:U/C:L/I:N/A:N");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2020-29480");

  script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"false");
  script_set_attribute(attribute:"vendor_unpatched", value:"true");

  script_set_attribute(attribute:"vuln_publication_date", value:"2020/12/15");
  script_set_attribute(attribute:"plugin_publication_date", value:"2025/08/30");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:16.04:-:lts");
  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:"p-cpe:/a:canonical:ubuntu_linux:xen");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"Misc.");

  script_copyright(english:"This script is Copyright (C) 2025 and is owned by Tenable, Inc. or an Affiliate thereof.");

  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");

  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": "libxen-4.6"},
          {"reference": "libxen-dev"},
          {"reference": "libxenstore3.0"},
          {"reference": "xen-hypervisor-4.4-amd64"},
          {"reference": "xen-hypervisor-4.4-arm64"},
          {"reference": "xen-hypervisor-4.4-armhf"},
          {"reference": "xen-hypervisor-4.5-amd64"},
          {"reference": "xen-hypervisor-4.5-arm64"},
          {"reference": "xen-hypervisor-4.5-armhf"},
          {"reference": "xen-hypervisor-4.6-amd64"},
          {"reference": "xen-hypervisor-4.6-arm64"},
          {"reference": "xen-hypervisor-4.6-armhf"},
          {"reference": "xen-system-amd64"},
          {"reference": "xen-system-arm64"},
          {"reference": "xen-system-armhf"},
          {"reference": "xen-utils-4.6"},
          {"reference": "xen-utils-common"},
          {"reference": "xenstore-utils"}
        ]
      }
    ]
  },
  "Ubuntu Linux-18.04": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "18.04",
        "pkgs": [
          {"reference": "libxen-4.9"},
          {"reference": "libxen-dev"},
          {"reference": "libxenstore3.0"},
          {"reference": "xen-hypervisor-4.6-amd64"},
          {"reference": "xen-hypervisor-4.6-arm64"},
          {"reference": "xen-hypervisor-4.6-armhf"},
          {"reference": "xen-hypervisor-4.7-amd64"},
          {"reference": "xen-hypervisor-4.7-arm64"},
          {"reference": "xen-hypervisor-4.7-armhf"},
          {"reference": "xen-hypervisor-4.8-amd64"},
          {"reference": "xen-hypervisor-4.8-arm64"},
          {"reference": "xen-hypervisor-4.8-armhf"},
          {"reference": "xen-hypervisor-4.9-amd64"},
          {"reference": "xen-hypervisor-4.9-arm64"},
          {"reference": "xen-hypervisor-4.9-armhf"},
          {"reference": "xen-system-amd64"},
          {"reference": "xen-system-arm64"},
          {"reference": "xen-system-armhf"},
          {"reference": "xen-utils-4.9"},
          {"reference": "xen-utils-common"},
          {"reference": "xenstore-utils"}
        ]
      }
    ]
  },
  "Ubuntu Linux-20.04": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "20.04",
        "pkgs": [
          {"reference": "xen"}
        ]
      }
    ]
  }
};

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_WARNING,
      extra      : report
  );
  exit(0);
}
else
{
  audit(AUDIT_HOST_NOT, 'affected');
}