Ubuntu 16.04 LTS / 18.04 LTS / 20.04 LTS : Dnsmasq regression (USN-4698-2)

##
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Ubuntu Security Notice USN-4698-2. 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(147987);
  script_version("1.7");
  script_set_attribute(attribute:"plugin_modification_date", value:"2024/08/28");
  script_xref(name:"USN", value:"4698-2");

  script_name(english:"Ubuntu 16.04 LTS / 18.04 LTS / 20.04 LTS : Dnsmasq regression (USN-4698-2)");

  script_set_attribute(attribute:"synopsis", value:
"The remote Ubuntu host is missing a security update.");
  script_set_attribute(attribute:"description", value:
"The remote Ubuntu 16.04 LTS / 18.04 LTS / 20.04 LTS host has packages installed that are affected by a vulnerability as
referenced in the USN-4698-2 advisory.

    USN-4698-1 fixed vulnerabilities in Dnsmasq. The updates introduced regressions in certain environments
    related to issues with multiple queries, and issues with retries. This update fixes the problem.

    Original advisory details:

    Moshe Kol and Shlomi Oberman discovered that Dnsmasq incorrectly handled

    memory when sorting RRsets. A remote attacker could use this issue to cause

    Dnsmasq to hang, resulting in a denial of service, or possibly execute

    arbitrary code. (CVE-2020-25681, CVE-2020-25687)

    Moshe Kol and Shlomi Oberman discovered that Dnsmasq incorrectly handled

    extracting certain names. A remote attacker could use this issue to cause

    Dnsmasq to hang, resulting in a denial of service, or possibly execute

    arbitrary code. (CVE-2020-25682, CVE-2020-25683)

    Moshe Kol and Shlomi Oberman discovered that Dnsmasq incorrectly

    implemented address/port checks. A remote attacker could use this issue to

    perform a cache poisoning attack. (CVE-2020-25684)

    Moshe Kol and Shlomi Oberman discovered that Dnsmasq incorrectly

    implemented query resource name checks. A remote attacker could use this

    issue to perform a cache poisoning attack. (CVE-2020-25685)

    Moshe Kol and Shlomi Oberman discovered that Dnsmasq incorrectly handled

    multiple query requests for the same resource name. A remote attacker could

    use this issue to perform a cache poisoning attack. (CVE-2020-25686)

    It was discovered that Dnsmasq incorrectly handled memory during DHCP

    response creation. A remote attacker could possibly use this issue to

    cause Dnsmasq to consume resources, leading to a denial of service. This

    issue only affected Ubuntu 16.04 LTS, Ubuntu 18.04 LTS, and Ubuntu 20.04

    LTS. (CVE-2019-14834)

Tenable has extracted the preceding description block directly from the Ubuntu security advisory.

Note that Nessus has not tested for this issue 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-4698-2");
  script_set_attribute(attribute:"solution", value:
"Update the affected packages.");
  script_set_attribute(attribute:"risk_factor", value:"None");

  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:"2021/02/24");
  script_set_attribute(attribute:"patch_publication_date", value:"2021/02/24");
  script_set_attribute(attribute:"plugin_publication_date", value:"2021/03/23");

  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:dnsmasq");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:dnsmasq-base");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:dnsmasq-base-lua");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:dnsmasq-utils");
  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) 2021-2024 Canonical, Inc. / NASL script (C) 2021-2024 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("ssh_get_info.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 (! ('16.04' >< os_release || '18.04' >< os_release || '20.04' >< os_release)) audit(AUDIT_OS_NOT, 'Ubuntu 16.04 / 18.04 / 20.04', '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 pkgs = [
    {'osver': '16.04', 'pkgname': 'dnsmasq', 'pkgver': '2.75-1ubuntu0.16.04.8'},
    {'osver': '16.04', 'pkgname': 'dnsmasq-base', 'pkgver': '2.75-1ubuntu0.16.04.8'},
    {'osver': '16.04', 'pkgname': 'dnsmasq-utils', 'pkgver': '2.75-1ubuntu0.16.04.8'},
    {'osver': '18.04', 'pkgname': 'dnsmasq', 'pkgver': '2.79-1ubuntu0.3'},
    {'osver': '18.04', 'pkgname': 'dnsmasq-base', 'pkgver': '2.79-1ubuntu0.3'},
    {'osver': '18.04', 'pkgname': 'dnsmasq-base-lua', 'pkgver': '2.79-1ubuntu0.3'},
    {'osver': '18.04', 'pkgname': 'dnsmasq-utils', 'pkgver': '2.79-1ubuntu0.3'},
    {'osver': '20.04', 'pkgname': 'dnsmasq', 'pkgver': '2.80-1.1ubuntu1.3'},
    {'osver': '20.04', 'pkgname': 'dnsmasq-base', 'pkgver': '2.80-1.1ubuntu1.3'},
    {'osver': '20.04', 'pkgname': 'dnsmasq-base-lua', 'pkgver': '2.80-1.1ubuntu1.3'},
    {'osver': '20.04', 'pkgname': 'dnsmasq-utils', 'pkgver': '2.80-1.1ubuntu1.3'}
];

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 (osver && pkgname && pkgver) {
    if (ubuntu_check(osver:osver, pkgname:pkgname, pkgver:pkgver)) flag++;
  }
}

if (flag)
{
  var extra = '';
  extra += ubuntu_report_get();
  security_report_v4(
    port       : 0,
    severity   : SECURITY_NOTE,
    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, 'dnsmasq / dnsmasq-base / dnsmasq-base-lua / dnsmasq-utils');
}